Artículos de revistas: "Drinking water Salmonella typhimurium. Biofilms"

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Schaefer, L. M., V. S. Brözel y S. N. Venter. "Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms". Journal of Water and Health 11, n.º 4 (6 de agosto de 2013): 629–35. http://dx.doi.org/10.2166/wh.2013.208.

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Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of non-typhoidal Salmonella in simulated drinking water biofilms was investigated. The ability of Salmonella to form biofilms in monoculture and the fate and persistence of Salmonella in a mixed aquatic biofilm was examined. In monoculture S. Typhimurium formed loosely structured biofilms. Salmonella colonized established multi-species drinking water biofilms within 24 hours, forming micro-colonies within the biofilm. S. Typhimurium was also released at high levels from the drinking water-associated biofilm into the water passing through the system. This indicated that Salmonella could enter into, survive and grow within, and be released from a drinking water biofilm. The ability of Salmonella to survive and persist in a drinking water biofilm, and be released at high levels into the flow for recolonization elsewhere, indicates the potential for a persistent health risk to consumers once a network becomes contaminated with this bacterium.

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Yadav, Neha, Sradhanjali Singh y Sanjeev K. Goyal. "Effect of Seasonal Variation on Bacterial Inhabitants and Diversity in Drinking Water of an Office Building, Delhi". Air, Soil and Water Research 12 (enero de 2019): 117862211988233. http://dx.doi.org/10.1177/1178622119882335.

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The work reported in this article raises some serious concern about the drinking water quality and its standards. Mere presence or absence of an indicator organism does not assure that the water is safe for drinking purposes. Instead of infecting directly, many pathogens pass through a host and retrieve their virulent properties by causing diseases/infections in humans. Pathogenic bacteria which exist in aquatic habitats show a unique and peculiar pattern of appearing or reappearing in different microenvironments. Several factors that prevail in the water system make a safe house for the growth, proliferation, and colonization of microorganisms. In our case, 6 different microenvironments inside the premises of an office building were taken as the sampling sites to study the effect of seasonal variations (summer, monsoon, and post-monsoon/winter) on bacterial diversity and inhabitants. Results suggested that the presence of total and thermotolerant coliforms were highest in the monsoon followed by summer and post-monsoon/winter seasons. To know the bacterial diversity and pattern of appearance/reappearance prevailing in the water system, bacterial strains were analyzed by 16S rRNA sequencing which showed Pseudomonas putida to be the predominant identified bacterial strain occurring about 38% to 77% in all 3 seasons. This was followed by Lelliottia nimipressuralis (6%-21%), Escherichia coli (4%-18%), Salmonella typhimurium and Aeromonas dhakensis (4%-10% each), and Klebsiella pneumoniae (5%-6%). Despite the absence of other opportunistic bacteria, P putida was reported to be present as a single organism in water coolers and dispensers. This might be due to the persistent nature of P putida in low-nutrient environments and capable of colonizing by forming a rigid biofilm inside the water cooler/dispenser which makes a conducive environment for it.

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Nocker, Andreas y Anne K. Camper. "Selective Removal of DNA from Dead Cells of Mixed Bacterial Communities by Use of Ethidium Monoazide". Applied and Environmental Microbiology 72, n.º 3 (marzo de 2006): 1997–2004. http://dx.doi.org/10.1128/aem.72.3.1997-2004.2006.

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ABSTRACT The distinction between viable and dead bacterial cells poses a major challenge in microbial diagnostics. Due to the persistence of DNA in the environment after cells have lost viability, DNA-based quantification methods overestimate the number of viable cells in mixed populations or even lead to false-positive results in the absence of viable cells. On the other hand, RNA-based diagnostic methods, which circumvent this problem, are technically demanding and suffer from some drawbacks. A promising and easy-to-use alternative utilizing the DNA-intercalating dye ethidium monoazide bromide (EMA) was published recently. This chemical is known to penetrate only into “dead” cells with compromised cell membrane integrity. Subsequent photoinduced cross-linking was reported to inhibit PCR amplification of DNA from dead cells. We provide evidence here that in addition to inhibition of amplification, most of the DNA from dead cells is actually lost during the DNA extraction procedure, probably together with cell debris which goes into the pellet fraction. Exposure of bacteria to increasing stress and higher proportions of dead cells in defined populations led to increasing loss of genomic DNA. Experiments were performed using Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium as model pathogens and using real-time PCR for their quantification. Results showed that EMA treatment of mixed populations of these two species provides a valuable tool for selective removal of DNA of nonviable cells by using conventional extraction protocols. Furthermore, we provide evidence that prior to denaturing gradient gel electrophoresis, EMA treatment of a mature mixed-population drinking-water biofilm containing a substantial proportion of dead cells can result in community fingerprints dramatically different from those for an untreated biofilm. The interpretation of such fingerprints can have important implications in the field of microbial ecology.

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JUNG, YONG SOO, ROBIN C. ANDERSON, JAMES A. BYRD, THOMAS S. EDRINGTON, RANDLE W. MOORE, TODD R. CALLAWAY, JACK McREYNOLDS y DAVID J. NISBET. "Reduction of Salmonella Typhimurium in Experimentally Challenged Broilers by Nitrate Adaptation and Chlorate Supplementation in Drinking Water†". Journal of Food Protection 66, n.º 4 (1 de abril de 2003): 660–63. http://dx.doi.org/10.4315/0362-028x-66.4.660.

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The effects of two feed supplements on Salmonella Typhimurium in the ceca of market-age broilers were determined. Broilers orally challenged 6 days before slaughter with a novobiocin- and nalidixic acid–resistant strain of Salmonella Typhimurium were divided into one of four groups (20 birds each). The first group (the control group) received no treatment, the second group received sodium nitrate (SN) treatment (574 mg of NaNO3 per kg of feed), the third group received experimental chlorate product (ECP) treatment (15 mM NaClO3 equivalents), and the fourth group received ECP treatment in combination with SN treatment. The SN treatment was administered via feed for 5 days immediately before slaughter, and ECP was provided via ad libitum access to drinking water for the last 2 days before slaughter. Cecal contents were subjected to bacterial analysis. Significant (P < 0.05) Salmonella Typhimurium reductions (ca. 2 log units) relative to levels for untreated control broilers were observed for broilers receiving ECP in combination with SN. The ECP-only treatment resulted in significant (P < 0.05) reductions (ca. 0.8 log) of Salmonella Typhimurium in trial 2. We hypothesize that increasing Salmonella Typhimurium nitrate reductase activity resulted in increased enzymatic reduction of chlorate to chlorite, with a concomitant decrease in cecal Salmonella Typhimurium levels. On the basis of these results, preadaptation with SN followed by ECP supplementation immediately preharvest could be a potential strategy for the reduction of Salmonella Typhimurium in broilers.

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September, S. M., F. A. Els, S. N. Venter y V. S. Brözel. "Prevalence of bacterial pathogens in biofilms of drinking water distribution systems". Journal of Water and Health 5, n.º 2 (1 de junio de 2007): 219–27. http://dx.doi.org/10.2166/wh.2007.004b.

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Water for human consumption is required to be free from any bacteria that might pose a health risk. The presence of biofilms in the drinking water distribution system may play a role in the presence of potential pathogens in the drinking water supply. Ninety-five biofilm samples from various parts of South Africa were tested for the presence of Escherichia coli, Aeromonas, Pseudomonas, Salmonella, Shigella and Vibrio spp. Members of these genera were quantified by the three-tube most probable number (MPN) approach using enrichment broths and plating on selective agars. The heterotrophic culturable counts were determined for both the planktonic and biofilm phases of the samples. Biofilm density varied between 10 and 1.9 × 109 colony forming units cm−2. The 16S rRNA identity of the putative pathogenic isolates revealed that high numbers of Aeromonas, Pseudomonas,Klebsiella and Enterobacter were present, but no putative Salmonella and Shigella could be confirmed. None of the Pseudomonas isolates belonged to the pathogenic Pseudomonas aeruginosa or Pseudomonas mendocina while the Aeromonas isolates showed relatedness to known pathogenic members of this group.

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Pasmans, Frank, Kris Baert, An Martel, Alain Bousquet-Melou, Ruben Lanckriet, Sandra De Boever, Filip Van Immerseel, Venessa Eeckhaut, Patrick de Backer y Freddy Haesebrouck. "Induction of the Carrier State in Pigeons Infected with Salmonella enterica Subspecies enterica Serovar Typhimurium PT99 by Treatment with Florfenicol: a Matter of Pharmacokinetics". Antimicrobial Agents and Chemotherapy 52, n.º 3 (7 de enero de 2008): 954–61. http://dx.doi.org/10.1128/aac.00575-07.

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ABSTRACT Paratyphoid caused by Salmonella enterica subsp. enterica serovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonella serovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonella infection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonella strain used (4 μg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 μg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonella serovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonella shedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency.

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Pavlova, I. B., A. B. Kononenko y D. A. Bannikova. "MORPHOLOGY OF SALMONELLA POPULATIONS IN WATER MEDIUM AND THEIR ABILITY TO FORM BIOFILMS". Problems of Veterinary Sanitation, Hygiene and Ecology 1, n.º 3 (2019): 294–301. http://dx.doi.org/10.36871/vet.san.hyg.ecol.201903009.

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The aim of the work is to study the survival strategy of salmonella populations in water medium with the formation of biofilms and L-transformation processes. Materials and methods. Salmonella typhimurium №1957 was chosen as a test culture. For the quantitative account of the growth of Salmonella and their morphology, an accelerated method of serial dilution was used with a seeding of 0,05 ml on membrane filters No. 4-5 production «Vladipor» placed on the dense nutrient medium of the BSA. Biochemical properties were determined by accelerated method using MTS-Salm system. For SEM, the preparations were fixed with an aqueous solution of glutaraldehyde, dehydrated with propylene oxide. The preparations were sprayed with platinum or gold ions on the «Hitachi-E-102» installation. The work was carried out on a scanning electron microscope Hitachi TM3030. Research results. The study of Salmonella preparations from water samples in vitro by method SEM showed that after 7 days of Salmonella existence in water at temperature of 26 ° C, the populations were united in microcolonies, covered from all sides by dense biofilm. After 2 months, the main part of the salmonella population was represented by the formed multilayer biofilm. After 6 months (observation period) at 26°C, the population of Salmonella cells was at the stage of L-transformation.

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Angelopoulou, Michailia, Konstantina Tzialla, Angeliki Voulgari, Mary Dikeoulia, Ioannis Raptis, Sotirios Elias Kakabakos y Panagiota Petrou. "Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor". Sensors 21, n.º 8 (10 de abril de 2021): 2683. http://dx.doi.org/10.3390/s21082683.

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Biosensors represent an attractive approach for fast bacteria detection. Here, we present an optical biosensor for the detection of Salmonella typhimurium lipopolysaccharide (LPS) and Salmonella bacteria in drinking water, based on white light reflectance spectroscopy. The sensor chip consisted of a Si die with a thin SiO2 layer on top that was transformed into a biosensor through the immobilization of Salmonella LPS. The optical setup included a reflection probe with seven 200 μm fibers, a visible and near-infrared light source, and a spectrometer. The six fibers at the reflection probe circumference were coupled with the light source and illuminated the biosensor chip vertically, whereas the central fiber collected the reflected light and guided it to the spectrometer. A competitive immunoassay configuration was adopted for the analysis. Accordingly, a mixture of LPS or bacteria solution, pre-incubated for 15 min, with an anti-Salmonella LPS antibody was pumped over the chip followed by biotinylated secondary antibody and streptavidin for signal enhancement. The binding of the free anti-Salmonella antibody to chip-immobilized LPS led to a shift of the reflectance spectrum that was inversely related to the analyte concentration (LPS or bacteria) in the calibrators or samples. The total assay duration was 15 min, and the detection limits achieved were 4 ng/mL for LPS and 320 CFU/mL for bacteria. Taking into account the low detection limits, the short analysis time, and the small size of the chip and instrumentation employed, the proposed immunosensor could find wide application for bacteria detection in drinking water.

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Shankar, Prem, Jyotsna Mishra, Vijaya Bharti, Deepak Parashar y Sarman Singh. "Multiplex PCR assay for simultaneous detection and differentiation of Entamoeba histolytica, Giardia lamblia, and Salmonella spp. in the municipality-supplied drinking water". Journal of Laboratory Physicians 11, n.º 03 (julio de 2019): 275–80. http://dx.doi.org/10.4103/jlp.jlp_66_18.

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Abstract BACKGROUND: The contamination with Entamoeba histolytica, Giardia lamblia, and Salmonella spp. in drinking water is the most prevalent in Indian subcontinent, but often difficult to detect all these pathogens from the drinking water. MATERIALS AND METHODS: A multiplex polymerase chain reaction (mPCR) method was developed to detect contamination of municipality-supplied drinking water with E. histolytica, G. lamblia, and Salmonella spp. The primers were designed to target small subunit of 16S rRNA type gene of E. histolytica and G. lamblia, and invasive A gene of Salmonella typhimurium. The optimized mPCR assay was applied on 158 municipality-supplied drinking water samples collected from Delhi. RESULTS: Out of total 158 water samples, 89 (56.32%) were found positive for the targeted pathogens by mPCR while conventional methods could be detected only in 11 (6.96%) samples. The mPCR assay showed 100% sensitivity and specificity for these pathogens in comparison with culture and microscopic detection. Of the 89 mPCR-positive samples, G. lamblia, E. histolytica, and Salmonella spp. were present in 35 (22.15%), 26 (16.45%), and 28 (17.72%), respectively. Nine (5.69%) samples were positive for both E. histolytica and G. lamblia, 10 (6.32%) were positive for G. lamblia and Salmonella spp., and 8 (5.06%) had Salmonella spp. and E. histolytica. Nonetheless, 3 (1.89%) samples were positive for all three pathogens. CONCLUSIONS: The present assay is an alternative to conventional methods to serve as highly sensitive, specific, and economical means for water quality surveillance to detect the outbreak caused by E. histolytica, G. lamblia, and Salmonella spp. pathogens.

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Momba, Maggy N. B., Veronica K. Malakate y Jacques Theron. "Abundance of pathogenic Escherichia coli, Salmonella typhimurium and Vibrio cholerae in Nkonkobe drinking water sources". Journal of Water and Health 4, n.º 3 (1 de abril de 2006): 289–96. http://dx.doi.org/10.2166/wh.2006.011.

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In order to study the prevalence of enteric pathogens capable of causing infection and disease in the rural communities of Nkonkobe, bacterial isolates were collected from several surface water and groundwater sources used by the community for their daily water needs. By making use of selective culture media and the 20E API kit, presumptive Escherichia coli, Salmonella spp. and Vibrio cholerae isolates were obtained and then analysed by polymerase chain reaction assays (PCR). The PCR successfully amplified from water samples a fragment of E. coli uidA gene that codes for β-D-glucuronidase which is a highly specific characteristic of enteropathogenic E. coli, enterotoxigenic E. coli and entero-invasive E. coli. The PCR also amplified the epsM gene from water samples containing toxigenic V. cholerae. Although E. coli was mostly detected in groundwater sources, toxigenic V. cholerae was detected in both surface and groundwater sources. There was a possibility of Salmonella typhimurium in Ngqele and Dyamala borehole water samples. The presence of these pathogenic bacteria in the above drinking water sources may pose a serious health risk to consumers.

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Armon, R., J. Starosvetzky, T. Arbel y M. Green. "Survival of legionella pneumophila and salmonella typhimurium in biofilm systems". Water Science and Technology 35, n.º 11-12 (1 de junio de 1997): 293–300. http://dx.doi.org/10.2166/wst.1997.0749.

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Biofilms are found in many water supply systems where they form an environment in which different bacteria can be entrapped for long periods. Besides the aesthetic aspect, biofilm has a major contribution in biocorrosion, disinfection inefficiency and possibly may act as a reservoir for pathogenic and non-pathogenic microorganisms. In the present study, two pathogenic bacteria Legionella pneumophila and Salmonella typhimurium WG-49 were introduced into a biofilm simulation flow system supplied with sterile and non-sterile tap water. The survival of these microorganisms into the biofilm formed on glass and PVC coupons at two temperatures (24°C and 36°C) was compared in this system. On glass supports, under sterile conditions at 36°C, Legionella pneumophila sg3 decreased by 6 logs during 40d continuous recirculation. Under non-sterile conditions, L. pneumophila decreased by only half log <48d. S. typhimurium WG-49 under the same conditions showed an increase of 3 logs in the sterile system for 31d, while in the non-sterile system it dropped by only 0.5 log for 20d. At 24°C, L. pneumophila remained stable for >40d under sterile conditions. In non-sterile conditions, L. pneumophila dropped by 1 log for 35d. S. typhimurium, in a sterile system, remained almost unchanged, while in the non-sterile system an increase of 3 logs was observed for the first 21d and thereafter a decrease of 2 logs for the next 21d of the experiment. L. pneumophila on PVC coupons at 36°C survived better compared with glass support. The experimental data show that survival of pathogenic microorganisms into biofilm is variable and depends on many factors, making the survival prediction a difficult task. However, the survival results of L. pneumophila and S. typhimurium in time terms should raise important questions on their potential threat in water distribution systems.

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Ailes, Elizabeth, Philip Budge, Manjunath Shankar, Sarah Collier, William Brinton, Alicia Cronquist, Melissa Chen, Andrew Thornton, Michael J. Beach y Joan M. Brunkard. "Economic and Health Impacts Associated with a Salmonella Typhimurium Drinking Water Outbreak−Alamosa, CO, 2008". PLoS ONE 8, n.º 3 (18 de marzo de 2013): e57439. http://dx.doi.org/10.1371/journal.pone.0057439.

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Kadry, Mona, Sara Mohamed Nader, Sohad M. Dorgham y Mai M. Kandil. "Molecular diversity of the invA gene obtained from human and egg samples". July-2019 12, n.º 7 (julio de 2019): 1033–38. http://dx.doi.org/10.14202/vetworld.2019.1033-1038.

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Background and Aim: Salmonellosis is one of the most common foodborne bacterial diseases in the world. The great majority of Salmonella infections in humans are foodborne with Salmonella enterica and Salmonella Typhimurium accounting for a major part of the problem. The objective of this study was to investigate the presence of invA gene in strains of Salmonellae isolated from eggs and diarrheal swabs from human cases. In addition, the relationship between invA gene nucleotide sequences from different sources (human stool and egg samples) have been studied through phylogenetic tree. Materials and Methods: One hundred and seventy eggs (eggshell and its contents) and 160 stool swabs samples were collected from four poultry farms and medical hospital in Giza Governorate. Results: The study reported the presence of two Salmonella strains in eggshell surface with an overall isolation rate of 1.2 and 0% of the egg content. Salmonella Enteritidis and Salmonella Typhimurium were isolated from eggshell surface with an incidence of 50% for each strain. Six salmonella strains were isolated from human stool with an incidence of 3.75%; the isolated strains are S. Typhimurium, S. Enteritidis, Salmonella Virchow, Salmonella Haifa, and Salmonella Kentucky with an incidence of 33.3%, 16.6%, 16.6%, 16.6%, and 16.6%, respectively. Among eight Salmonella strains, invA gene was detected with percentage of 50%. The phylogenetic analysis of the sequences invA gene, from two isolates included in this study and five isolates retrieved from GenBank showed that sequence from human, layer hens, egg, and water in the same clusters. Conclusion: Close relation between drinking contaminated water and layer hens and contaminated water is one such source.

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Sekirov, Inna, Nicola M. Tam, Maria Jogova, Marilyn L. Robertson, Yuling Li, Claudia Lupp y B. Brett Finlay. "Antibiotic-Induced Perturbations of the Intestinal Microbiota Alter Host Susceptibility to Enteric Infection". Infection and Immunity 76, n.º 10 (4 de agosto de 2008): 4726–36. http://dx.doi.org/10.1128/iai.00319-08.

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ABSTRACT Intestinal microbiota comprises microbial communities that reside in the gastrointestinal tract and are critical to normal host physiology. Understanding the microbiota's role in host response to invading pathogens will further advance our knowledge of host-microbe interactions. Salmonella enterica serovar Typhimurium was used as a model enteric pathogen to investigate the effect of intestinal microbiota perturbation on host susceptibility to infection. Antibiotics were used to perturb the intestinal microbiota. C57BL/6 mice were treated with clinically relevant doses of streptomycin and vancomycin in drinking water for 2 days, followed by oral infection with Salmonella enterica serovar Typhimurium. Alterations in microbiota composition and numbers were evaluated by fluorescent in situ hybridization, differential plating, and Sybr green staining. Antibiotics had a dose-dependent effect on intestinal microbiota composition. The chosen antibiotic regimen did not significantly alter the total numbers of intestinal bacteria but altered the microbiota composition. Greater preinfection perturbations in the microbiota resulted in increased mouse susceptibility to Salmonella serovar Typhimurium intestinal colonization, greater postinfection alterations in the microbiota, and more severe intestinal pathology. These results suggest that antibiotic treatment alters the balance of the microbial community, which predisposes the host to Salmonella serovar Typhimurium infection, demonstrating the importance of a healthy microbiota in host response to enteric pathogens.

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Byrd, JA, RC Anderson, TR Callaway, RW Moore, KD Knape, LF Kubena, RL Ziprin y DJ Nisbet. "Effect of experimental chlorate product administration in the drinking water on Salmonella typhimurium contamination of broilers". Poultry Science 82, n.º 9 (septiembre de 2003): 1403–6. http://dx.doi.org/10.1093/ps/82.9.1403.

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Kaur, Rajanbir y Rajinder Kaur. "Microbial Diversity and their Biofilm Formation Potential in Pipes of Water Distribution System". Asian Journal of Water, Environment and Pollution 17, n.º 4 (31 de octubre de 2020): 113–17. http://dx.doi.org/10.3233/ajw200058.

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Microbes are ubiquitous in surface as well as in ground water and some of them can make their way into potable water distribution systems. Contaminated soil with human and animal fecal matter, ill-maintained water and sewage pipelines, poor sanitation and personal hygiene are the main factors responsible for the presence of microbial pathogens in the drinking water. The presence of water-borne microbes in the potable drinking water systems determines its quality. Common microbes present in contaminated water are Shigella, Escherichia coli, Vibrio cholerae, Pseudomonas sp, Salmonella sp etc. The water-borne pathogens that reside and reproduce in water distribution system causes infection of gastrointestinal tract, urinary tract, skin, and lymph nodes. When these pathogens enter into the water distribution system pipelines they form biofilms. The formation of biofilm is a key component in microbial studies. Biofilm is the sessile aggregation of bacterial cells that adhere to each other on living or non-living surfaces and forms extracellular polymeric substances (EPS). The surface physico-chemical properties of both bacteria and substratum were important for the establishment of bacterial adhesion. Bacteria forming biofilms possesses different growth patterns, responds to specific micro-environmental conditions for the formation of structurally complex mature biofilms. In water distribution systems, adhesion of microbes to the water pipelines initiate biofilm formation which in return reduces the quality of potable water and increases the corrosion of pipes.

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Chen, Yibao, Erchao Sun, Jiaoyang Song, Yigang Tong y Bin Wu. "Three Salmonella enterica serovar Enteritidis bacteriophages from the Siphoviridae family are promising candidates for phage therapy". Canadian Journal of Microbiology 64, n.º 11 (noviembre de 2018): 865–75. http://dx.doi.org/10.1139/cjm-2017-0740.

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Salmonella is a common and widely distributed foodborne pathogen that is frequently implicated in gastrointestinal infections. The emergence and spread of Salmonella strains resistant to multiple antibiotics poses a significant health threat, highlighting the urgent need for early and effective therapeutic strategies. We isolated a total of 32 phages from water samples and anal swabs from pigs. Of these, three phages that produced large, clear plaques were selected for further study using the following methods: electron microscopy, analysis of the life cycle parameters, genetic analysis, inhibition of bacterial growth, and activity against biofilms. The three Salmonella phages (vB_SenS_CSP01, vB_SenS_PHB06, and vB_SenS_PHB07) were assigned to the family Siphoviridae on the basis of their morphology. All showed polyvalent infectivity, and individual phages or phage cocktails could inhibit the growth of host Salmonella enterica serovar Enteritidis strains or reduce biofilm formation by Salmonella enterica serovar Typhimurium. In summary, these three phages merit further research as biocontrol agents for Salmonella infection.

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Anderson, Robin C., Todd R. Callaway, Kenneth J. Genovese, Timothy J. Anderson, Thomas S. Edrington, Toni L. Poole, Kenneth M. Bischoff y David J. Nisbet. "Effect of Administering Sodium Chlorate in Drinking Water on Salmonella Typhimurium Concentrations in Weaned and Finished Pigs". Acta Veterinaria Scandinavica 44, Suppl 1 (2003): P63. http://dx.doi.org/10.1186/1751-0147-44-s1-p63.

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Boehm, Alexandria B., Cherrie Soetjipto y Dan Wang. "Solar inactivation of four Salmonella serovars in fresh and marine waters". Journal of Water and Health 10, n.º 4 (11 de octubre de 2012): 504–10. http://dx.doi.org/10.2166/wh.2012.084.

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Sunlight-mediated disinfection of water is of interest to both the drinking and recreational water quality community of researchers due to its potential to reduce microbial contamination and waterborne illness. Photo-inactivation of enteric bacteria has primarily been investigated using Escherichia coli and laboratory strains of model bacteria. The present study sought to document the photo-inactivation of environmental isolates of Salmonella in filter-sterilized natural seawater and freshwater and to test the hypothesis that diverse Salmonella serovars decay at similar rates both within and between water matrices. The inactivation of Salmonella enterica Typhimurium LT2, Typhimurium ST19, Heidelberg, and Mbandaka was examined in sunlit and dark microcosms. First order decay was observed in sunlit microcosms; the time until 90% inactivation was of the order of 10 min. A significant shoulder, of the order of 1 hr in length, was observed in the freshwater microcosms during which concentrations were stable. Serovar Mdandaka decayed more slowly than other serovars in both seawater and freshwater. The serovars were extremely stable in the dark microcosms showing little to no decay over 53 days. The results document intra-species variation in photo-inactivation, likely owing to differences in intracellular concentrations of photo-sensitizing molecules or molecules that quench reactive species.

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JUNG, Bock-Gie, Jin-A. LEE y Bong-Joo LEE. "Oxygenated Drinking Water Enhances Immune Activity in Pigs and Increases Immune Responses of Pigs during Salmonella Typhimurium Infection". Journal of Veterinary Medical Science 74, n.º 12 (2012): 1651–55. http://dx.doi.org/10.1292/jvms.12-0051.

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Pruul, Reet, Lars Nyland, Kimmo Peltonen, Marja Sorsa y Toomas Veidebaum. "Environmental Genotoxicity in an Estonian Oil Shale Industrial Area". Alternatives to Laboratory Animals 24, n.º 3 (junio de 1996): 419–22. http://dx.doi.org/10.1177/026119299602400317.

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The genotoxicity of environmental samples (ambient air, drinking and river waters, purified waste water and oil shale ash) from an oil shale mining and processing area was studied by using the Ames Salmonella/microsome assay. Salmonella typhimurium strains TA98 and YG1021 were used, with and without metabolic activation with rat liver homogenate S9. The water samples were treated with amberlite adsorbent XAD-2 for concentrating non-polar compounds. The air samples were collected on glass fibre filters by using a high volume air sampler, and extracted with dichloromethane by using a Soxhlet apparatus. The air samples were mutagenic in both strains, both with and without S9-mix. The air mutagenicity data were compared with data from similar tests on cigarette smoke condensate as a positive control. Based on the fact that the average 8-hour respiratory volume at occupational activities is between 10m3 and 20m3, the load of airborne mutagenicity at the cokery plant during one week was estimated to be equal to the mutagenicity produced by the mainstream smoke of one cigarette. The drinking and river water samples were tested with both strains, but no dose-related increases in water counts per plate were noted. The oil shale ash sample showed no mutagenic activity, but showed cytotoxicity at the higher doses tested.

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Moreira, Anderson De Melo, Willden John Lopes de Aguiar, Olavo Dionísio da Silva Dias, Tiago Medeiros da Silva, Amanda De Oliveira Sousa Cardoso, Letícia Batista dos Santos y Daniela Reis Joaquim de Freitas. "MICROBIOLOGICAL ANALYSIS OF DRINKING TAPS OF A PUBLIC UNIVERSITY IN THE STATE OF PIAUÍ". Revista Prevenção de Infecção e Saúde 3, n.º 1 (8 de septiembre de 2017): 8. http://dx.doi.org/10.26694/repis.v3i0.6243.

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Objectives: to carry out the microbiological analysis of drinking taps at a public university in the city of Teresina, Piauí. Methodology: Samples were collected from the faucets of 59 water fountains, inside the campus. Results: The results showed that all drinking water analyzed showed microbial growth, except one. Microorganisms such as Candida sp, Escherichia coli, Salmonella, Shigella, Staphylococcus (including S. aureus) and other enterobacteria were found. In order to verify the antimicrobial activity of S. aureus isolated populations, 5 different antimicrobial types were used, which showed 98% vancomycin resistance and 100% oxacillin resistance. Conclusion: microorganisms found as biofilms in taps are potentially pathogenic, especially S. aureus, which is heavily involved in community and hospital infections. The pattern of antimicrobial resistance found in isolated populations requires further studies and control measures to avoid its propagation.Análise microbiológica das torneiras dos bebedouros de uma universidade pública do estado do Piauí

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Enger, Kyle S., Emaly S. Leak, Tiong Gim Aw, Angela D. Coulliette y Joan B. Rose. "Antibacterial and antiviral effectiveness of two household water treatment devices that use monobrominated hydantoinylated polystyrene". Journal of Water and Health 14, n.º 6 (26 de agosto de 2016): 950–60. http://dx.doi.org/10.2166/wh.2016.153.

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Many different household water treatment (HWT) methods have been researched and promoted to mitigate the serious burden of diarrheal disease in developing countries. However, HWT methods using bromine have not been extensively evaluated. Two gravity-fed HWT devices (AquaSure™ and Waterbird™) were used to test the antimicrobial effectiveness of HaloPure® Br beads (monobrominated hydantoinylated polystyrene) that deliver bromine. As water flows over the beads, reactive bromine species are eluted, which inactivate microorganisms. To assess log10 reduction values (LRVs) for Vibrio cholerae, Salmonella enterica Typhimurium, bacteriophage MS2, human adenovirus 2 (HAdV2), and murine norovirus (MN), these organisms were added to potable water and sewage-contaminated water. These organisms were quantified before and after water treatment by the HWT devices. On average, 6 LRVs against Vibrio were attained, as well as 5 LRVs against Salmonella, 4 LRVs against MS2, 5 LRVs against HAdV2, and 3 LRVs against MN. Disinfection was similar regardless of whether sewage was present. Polymer beads delivering bromine to drinking water are a potentially effective and useful component of HWT methods in developing countries.

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24

Långmark, Jonas, Michael V. Storey, Nicholas J. Ashbolt y Thor-Axel Stenström. "Accumulation and Fate of Microorganisms and Microspheres in Biofilms Formed in a Pilot-Scale Water Distribution System". Applied and Environmental Microbiology 71, n.º 2 (febrero de 2005): 706–12. http://dx.doi.org/10.1128/aem.71.2.706-712.2005.

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ABSTRACT The accumulation and fate of model microbial “pathogens” within a drinking-water distribution system was investigated in naturally grown biofilms formed in a novel pilot-scale water distribution system provided with chlorinated and UV-treated water. Biofilms were exposed to 1-μm hydrophilic and hydrophobic microspheres, Salmonella bacteriophages 28B, and Legionella pneumophila bacteria, and their fate was monitored over a 38-day period. The accumulation of model pathogens was generally independent of the biofilm cell density and was shown to be dependent on particle surface properties, where hydrophilic spheres accumulated to a larger extent than hydrophobic ones. A higher accumulation of culturable legionellae was measured in the chlorinated system compared to the UV-treated system with increasing residence time. The fate of spheres and fluorescence in situ hybridization-positive legionellae was similar and independent of the primary disinfectant applied and water residence time. The more rapid loss of culturable legionellae compared to the fluorescence in situ hybridization-positive legionellae was attributed to a loss in culturability rather than physical desorption. Loss of bacteriophage 28B plaque-forming ability together with erosion may have affected their fate within biofilms in the pilot-scale distribution system. The current study has demonstrated that desorption was one of the primary mechanisms affecting the loss of microspheres, legionellae, and bacteriophage from biofilms within a pilot-scale distribution system as well as disinfection and biological grazing. In general, two primary disinfection regimens (chlorination and UV treatment) were not shown to have a measurable impact on the accumulation and fate of model microbial pathogens within a water distribution system.

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25

VICO, J. P., I. ROL, V. GARRIDO, B. SAN ROMÁN, M. J. GRILLÓ y R. C. MAINAR-JAIME. "Salmonellosis in Finishing Pigs in Spain: Prevalence, Antimicrobial Agent Susceptibilities, and Risk Factor Analysis". Journal of Food Protection 74, n.º 7 (1 de julio de 2011): 1070–78. http://dx.doi.org/10.4315/0362-028x.jfp-10-515.

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A herd-based survey of Salmonella in pigs was carried in a major pig producing region of Spain. Mesenteric lymph nodes were collected from the carcasses of 25 pigs from each of 80 herds at time of slaughter. Salmonella spp. were isolated from 31% of animals and 94% of herds. Within-herd prevalence ranged from 4 to 88%, with the prevalence in most herds being greater than 10%. A large diversity of Salmonella serotypes was found, with Typhimurium, 4,[5],12:i:–, and Rissen being the most prevalent. Two or more serotypes coexisted in 73% of the herds. Salmonella Typhimurium was present in 68% of the herds. Most (82%) of the Salmonella isolates belonged to serogroups targeted by enzyme-linked immunosorbent assay tests for pig salmonellosis. Resistance to at least one antimicrobial agent was detected in 73% of the strains, and one or more resistant strains were recovered from pigs in 93% of the herds. Antimicrobial agent resistance (AR) was more frequent among the most prevalent than it was among the rarer serotypes. Twenty-five multi-AR patterns were found. Resistance to three or more families of antimicrobial agents was found in 75% of AR strains. The finding that many of the herds yielded isolates of several multi-AR patterns indicates that Salmonella infections were acquired from multiple sources. High prevalence of Salmonella in herds was associated with lack of rodent control programs, herds from farms with only finishing pigs, herds managed by more than one full-time worker, herds for which the source of drinking water was not a city supply, and relatively long fattening times.

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Mohyla, P., S. F. Bilgili, O. A. Oyarzabal, C. C. Warf y G. K. Kemp. "Application of Acidified Sodium Chlorite in the Drinking Water to Control Salmonella serotype Typhimurium and Campylobacter jejuni in Commercial Broilers". Journal of Applied Poultry Research 16, n.º 1 (marzo de 2007): 45–51. http://dx.doi.org/10.1093/japr/16.1.45.

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Anderson, R. C., M. E. Hume, K. J. Genovese, T. R. Callaway, Y. S. Jung, T. S. Edrington, T. L. Poole, R. B. Harvey, K. M. Bischoff y D. J. Nisbet. "Effect of Drinking-Water Administration of Experimental Chlorate Ion Preparations on Salmonella enterica serovar Typhimurium Colonization in Weaned and Finished Pigs". Veterinary Research Communications 28, n.º 3 (abril de 2004): 179–89. http://dx.doi.org/10.1023/b:verc.0000017369.04003.2b.

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28

Villagrán-de la Mora, Zuamí, Olga Vázquez-Paulino, Hugo Avalos, Felipe Ascencio, Karla Nuño y Angélica Villarruel-López. "Effect of a Synbiotic Mix on Lymphoid Organs of Broilers Infected with Salmonella typhimurium and Clostridium perfringens". Animals 10, n.º 5 (19 de mayo de 2020): 886. http://dx.doi.org/10.3390/ani10050886.

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Synbiotic consumption can modulate immune response. This work involves studying the effect of a synbiotic on lymphoid organs and IgA of broilers infected with Salmonella typhimurium and Clostridium perfringens. A total of 258 one-day-old male broilers (Gallus gallus domesticus), line COBBAvian48 (free of growth-promoting antibiotics), were distributed into eight treatment groups. A symbiotic mix comprising Lactobacillus rhamnosus HN001 and Pediococcus acidilactici MA18/5 M as probiotics and 4.5% (0.045 g g−1) of Agave tequilana fructans as prebiotic per dose (one milliliter) was administered through drinking water the first day of life. Bursa, spleen and thymus were analyzed. Broilers treated with the synbiotic, whether or not infected with pathogens, had bigger bursa follicles than the non-treated (p < 0.05), and the ones from the synbiotic group had more lymphocytes than the control group (p < 0.05). Thymus follicles of the synbiotic group were bigger than the control group (p < 0.05). Lesions associated with Salmonella infection were found in the bursa, however, in the broilers treated with the synbiotic, the lesions were less intense and were not present after 32 days of life. The synbiotic mix can stimulate the bursa, increasing the size of their follicles and promoting the ability to resist infections caused by S. typhimurium in broilers.

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Bosshard, Franziska, Michael Berney, Michael Scheifele, Hans-Ulrich Weilenmann y Thomas Egli. "Solar disinfection (SODIS) and subsequent dark storage of Salmonella typhimurium and Shigella flexneri monitored by flow cytometry". Microbiology 155, n.º 4 (1 de abril de 2009): 1310–17. http://dx.doi.org/10.1099/mic.0.024794-0.

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Pathogenic enteric bacteria are a major cause of drinking water related morbidity and mortality in developing countries. Solar disinfection (SODIS) is an effective means to fight this problem. In the present study, SODIS of two important enteric pathogens, Shigella flexneri and Salmonella typhimurium, was investigated with a variety of viability indicators including cellular ATP levels, efflux pump activity, glucose uptake ability, and polarization and integrity of the cytoplasmic membrane. The respiratory chain of enteric bacteria was identified to be a likely target of sunlight and UVA irradiation. Furthermore, during dark storage after irradiation, the physiological state of the bacterial cells continued to deteriorate even in the absence of irradiation: apparently the cells were unable to repair damage. This strongly suggests that for S. typhimurium and Sh. flexneri, a relatively small light dose is enough to irreversibly damage the cells and that storage of bottles after irradiation does not allow regrowth of inactivated bacterial cells. In addition, we show that light dose reciprocity is an important issue when using simulated sunlight. At high irradiation intensities (>700 W m−2) light dose reciprocity failed and resulted in an overestimation of the effect, whereas reciprocity applied well around natural sunlight intensity (<400 W m−2).

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Karampoula, Doulgeraki, Fotiadis, Tampakaki y Nychas. "Monitoring Biofilm Formation and Microbial Interactions that May Occur During a Salmonella Contamination Incident across the Network of a Water Bottling Plant". Microorganisms 7, n.º 8 (2 de agosto de 2019): 236. http://dx.doi.org/10.3390/microorganisms7080236.

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The present study aims to monitor the ability of Salmonella to colonize and compete as a member of the mixed species biofilm within key points at a water bottling plant, in case of a contamination incident with this major foodborne pathogen. To achieve this goal, bacterial communities throughout the production line were collected and their identities were investigated by microbial counts and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). These bacterial communities alone or along with constructed Salmonella enterica serovar Typhimurium (ST) fluorescence-based bioreporters were left to form a biofilm on stainless steel for 6 days at 20 °C. ST bioreporters were constructed by introducing plasmids expressing EYFP (enhanced yellow fluorescent protein) fusions of the genes csgB, csrA, sspH2, and fliD into ST 14028S. The bead vortexing-plate counting method was applied for the enumeration of the biofilm population, while the behavior of the bioreporters was evaluated by fluorescence microscopy. From a set of 16 samples that were collected from the plant, species of Citrobacter, Staphylococcus, Pseudomonas, Bacillus, and Exiguobacterium were identified. The presence of these indigenous bacteria neither inhibited nor enhanced the biofilm formation of ST in mixed bacterial communities (p > 0.05). Furthermore, the csrA-based bioreporter was shown to be induced in multispecies biofilms with Citrobacter. In conclusion, this study enhanced our knowledge of bacterial interactions occurring within a biofilm in a water bottling plant.

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Lee, Ki-Hoon, Ji-Young Lee, Pantu Kumar Roy, Md Furkanur Rahaman Mizan, Md Iqbal Hossain, Si Hong Park y Sang-Do Ha. "Viability of Salmonella Typhimurium biofilms on major food-contact surfaces and eggshell treated during 35 days with and without water storage at room temperature". Poultry Science 99, n.º 9 (septiembre de 2020): 4558–65. http://dx.doi.org/10.1016/j.psj.2020.05.055.

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Abass, Anifowoshe T., Oladipo S. Olayinka, Adebayo O. Mutolib, Eboh O. Solomon, Abdussalam A. Rasheedat, Adegbenro A. Monsuru, Ojo T. Ifeoluwa et al. "Induction of Micronuclei, Base-pair Substitution Mutation and Excision-repair Deficient by Polluted Water from Asa River in Nigeria". Annals of Science and Technology 4, n.º 2 (1 de diciembre de 2019): 68–77. http://dx.doi.org/10.2478/ast-2019-0012.

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AbstractAsa river is a major river designated to supply millions of people of Ilorin, Kwara State, Nigeria potable water for drinking but its managements is of grave concern due to anthropogenic activities. Thus, evaluation of genotoxicity of this river was carried out by subjecting the water samples and fish therein to three bioassays (Micronucleus (MN) assay, Ames test and SOS-chromo test). Physicochemical parameters and heavy metals were analysed at three different stations (Aliara (SI), Unity (SII) and Tuyil (SIII)) of the river. In SII, most of the heavy metals analysed were above the acceptable limits compare to SI and SIII. The peripheral erythrocyte of the fishes (Oreochromis niloticus, Synodontis batensoda, Synodontis eupterus, Clarias gariepinus and Clarias angullaris) at SI and SII stations showed a significant (p<0.05) induction of MN and different nuclear abnormalities (NA). Water samples from the three stations subjected to Ames test (Salmonella typhimurium TA100) and SOS chromotests (Escherichia coli PQ37) at 25%, 50% and 100% concentrations showed statistically significant (p<0.05) induction of DNA damage at all concentrations in the two tester strains, thus indicating base-pair substitution mutation and excision-repairdeficient, respectively, by the water samples. Therefore, drinking of this water and/or consumption of fish from this river should be taken with caution to avoid a carcinogenic risk.

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Chu, Xiaona, Jiangyong Hu y Yang Xu. "Investigating the performance of a UV/H2O2 integrated flow-through system followed by free chlorine". Water Supply 12, n.º 6 (1 de octubre de 2012): 715–19. http://dx.doi.org/10.2166/ws.2012.046.

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Ultraviolet (UV) irradiation is an emerging technique for drinking water disinfection due to effective removal of enteric pathogens without generation of disinfection by-products (DBPs). In order to overcome the drawback of UV irradiation the integration of UV disinfection with sequential disinfectant was proposed. Among all the possible combinations and sequences, a UV/H2O2-Cl2 integrated system has proven to be effective in many previous studies. In this study, a UV/H2O2 flow-through system followed by free chlorine was built and studied. MS-2 coliphage, as a model for a waterborne virus, were inactivated to evaluate the disinfection capacity. Assimilable organic carbon (AOC) tests and an Ames assay using Salmonella typhimurium TA98 and TA100 on such a proposed integrated system were also performed to determine re-growth potential of bacteria and genotoxicity, respectively. Briefly, such a proposed flow-through system was effective in removal of MS-2 coliphage and no genotoxic potential was detected according to the results; however, an increase of AOC may raise concerns of bacterial re-growth along the subsequent distribution system.

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Hill, Vincent R., Amy L. Polaczyk, Donghyun Hahn, Jothikumar Narayanan, Theresa L. Cromeans, Jacquelin M. Roberts y James E. Amburgey. "Development of a Rapid Method for Simultaneous Recovery of Diverse Microbes in Drinking Water by Ultrafiltration with Sodium Polyphosphate and Surfactants". Applied and Environmental Microbiology 71, n.º 11 (noviembre de 2005): 6878–84. http://dx.doi.org/10.1128/aem.71.11.6878-6884.2005.

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ABSTRACT The ability to simultaneously concentrate diverse microbes is an important consideration for sample collection methods that are used for emergency response and environmental monitoring when drinking water may be contaminated with an array of unknown microbes. This study focused on developing a concentration method using ultrafilters and different combinations of a chemical dispersant (sodium polyphosphate [NaPP]) and surfactants. Tap water samples were seeded with bacteriophage MS2, Escherichia coli, Enterococcus faecalis, Cryptosporidium parvum, 4.5-μm microspheres, Salmonella enterica serovar Typhimurium, Bacillus globigii endospores, and echovirus 1. Ten-liter tap water samples were concentrated to ∼250 ml in 12 to 42 min, depending on the experimental condition. Initial experiments indicated that pretreating filters with fetal bovine serum or NaPP resulted in an increase in microbe recovery. The addition of NaPP to the tap water samples resulted in significantly higher microbe and microsphere recovery efficiencies. Backflushing of the ultrafilter was found to significantly improve recovery efficiencies. The effectiveness of backflushing was improved further with the addition of Tween 80 to the backflush solution. The ultrafiltration method developed in this study, incorporating the use of NaPP pretreatment and surfactant solution backflushing, was found to recover MS2, C. parvum, microspheres, and several bacterial species with mean recovery efficiencies of 70 to 93%. The mean recovery efficiency for echovirus 1 (49%) was the lowest of the microbes studied for this method. This research demonstrates that ultrafiltration can be effective for recovering diverse microbes simultaneously in tap water and that chemical dispersants and surfactants can be beneficial for improving microbial recovery using this technique.

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TODD, E. C. D. "Foodborne and Waterborne Disease in Canada-1984 Annual Summary". Journal of Food Protection 52, n.º 7 (1 de julio de 1989): 503–11. http://dx.doi.org/10.4315/0362-028x-52.7.503.

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Data on foodborne disease in Canada in 1984 are compared with those for 1983. A total of 1,181 incidents, comprising 1,016 outbreaks and 165 single cases, caused illnesses in 9,953 persons in 1984. These figures are the highest on record with almost double the number of cases occurring in 1983. Salmonella, Staphylococcus aureus, Clostridium perfringens, and Bacillus cereus were responsible for most of the illnesses. The main Salmonella serovars involved were S. typhimurium, S. enteritidis, and S. heidelberg. There were no incidents of parasitic infections or paralytic shellfish poisonings similar to 1983. Fifty-five incidents (82 cases) of chemical origin were recorded; extraneous matter and rancid compounds were the most frequently implicated. There were two deaths, one from botulism and the other from salmonellosis. Most of the illnesses were associated with meat and poultry (30.6% of incidents and 29.9% of cases). Dairy foods, particularly cheese, bakery products, and marine foods were also major vehicles of foodborne disease. Mishandling of food took place mainly in foodservice establishments (38.8% of incidents), homes (20.6% of incidents), and food processings establishments (5.9% of incidents). Chemicals, such as extraneous material and rancid compounds, were the agents associated with 40.0% of incidents caused by processors' mishandling. On a population basis, incidents were greatest in Ontario, followed by those in Quebec, British Columbia, and Manitoba. Details of several foodborne disease incidents are presented. In addition, seven incidents of waterborne disease were documented in 1984, five more than in 1983. Campylobacter, Salmonella and Yersinia were identified as pathogens associated with drinking water.

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Plewa, M. J., Y. Kargalioglu, D. Vankerk, R. A. Minear y E. D. Wagner. "Development of quantitative comparative cytotoxicity and genotoxicity assays for environmental hazardous chemicals". Water Science and Technology 42, n.º 7-8 (1 de octubre de 2000): 109–16. http://dx.doi.org/10.2166/wst.2000.0558.

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Mammalian cell asays can provide toxicological information that may be more relevant to human risk asessment than commonly used microbial tests. Rapid, semi-automated, quantitative mammalian cell cytotoxicity and genotoxicity assays were developed to analyze drinking water disinfection by-products (DBPs). These assays employ 96-well microplates; selected DBPs were analyzed with cultured Chinese hamster ovary (CHO) cells. The concentration of the DBPs that repressed 50% of CHO cell growth with a 72 h exposure was calculated as the %C1/2 value. Using these values the rank order (from highest to lowest cytotoxicity) was bromonitromethane, dibromonitromethane, tribromonitromethane, bromoacetic acid, dibromoacetic acid, and tribromoacetic acid. Genotoxicity analyses of the DBPs were conducted using the single cell gel electrophoresis (SCGE) assay. This assay detects genomic DNA damage at the level of the individual nucleus. Using SCGE genotoxic potency the rank order was bromoacetic acid> dibromonitromethane>>bromonitromethane>dibromoacetic acid>tribromoacetic acid. The relative cytotoxicity and genotoxicity of these agents were compared with Salmonella typhimurium. Studies of specific DBPs in mammalian cell systems are important to compare the toxicity of these hazardous water contaminants. Such knowledge is necessary for risk assessment and to assist in the formulation of public regulatory policies that protect the environment and the public health.

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WALDROUP, A., S. KANIAWATI y A. MAUROMOUSTAKOS. "Performance Characteristics and Microbiological Aspects of Broilers Fed Diets Supplemented with Organic Acids". Journal of Food Protection 58, n.º 5 (1 de mayo de 1995): 482–89. http://dx.doi.org/10.4315/0362-028x-58.5.482.

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The effects of supplementation of broiler diets with organic acids on live performance and microbiological parameters were evaluated in a series of experiments. In three trials lactic acid (LA) (0.25 to 2.00%) or fumaric acid (FA) (0.5 to 2.00%), and in two trials a formic/propionic acid blend (FP) (.125 to 1.00%) or citric acid (CA) (0.25 to 2.00%) was continually fed to broilers that were inoculated via the drinking water with 108 to 109 CFU/ml nalidixic acid–resistant Salmonella typhimurium (NAL-SAL) on days 2, 7, and 14. Cecal pH, weight and percentage (on a live-weight basis) were measured at 41 days of age. Performance variables were measured at 21 and 42 days. At 42 days birds were processed and the ceca and prechill carcasses were evaluated for incidence and levels of NAL-SAL. LA, FA, and CA had no adverse effects on live bird performance. The FP blend gave inconsistent results on body weight and feed consumption; the blend did not alter feed conversion or mortality. Neither LA nor FA affected cecal pH; however, the pH was altered when the FP blend or CA was fed. None of the acids affected cecal weight or percentage. None of the acids consistently reduced levels of NAL-SAL in the ceca or on the prechill carcasses. The results from this study and numerous others suggest that feeding organic acids to broilers is not a reliable means of controlling cecal colonization or carcass contamination by Salmonella. The results also suggest that reductions in cecal colonization by pathogens such as Salmonella do not necessarily result in processed carcasses that are contaminated to a lesser degree.

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MacFarlane, Amanda Shearer, Martin G. Schwacha y Toby K. Eisenstein. "In Vivo Blockage of Nitric Oxide with Aminoguanidine Inhibits Immunosuppression Induced by an Attenuated Strain of Salmonella typhimurium, PotentiatesSalmonella Infection, and Inhibits Macrophage and Polymorphonuclear Leukocyte Influx into the Spleen". Infection and Immunity 67, n.º 2 (1 de febrero de 1999): 891–98. http://dx.doi.org/10.1128/iai.67.2.891-898.1999.

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ABSTRACT Our laboratory has previously shown that after immunization with a strain of Salmonella typhimurium, SL3235, made avirulent by a blockage in the pathway of aromatic synthesis, murine splenocytes were profoundly suppressed in their capacity to mount an in vitro antibody plaque-forming cell (PFC) response to sheep erythrocytes. Evidence indicated that suppression was mediated by nitric oxide (NO), since the in vitro addition ofN G-monomethyl-l-arginine blocked suppression. The present studies examined the effect of blocking NO production on Salmonella-induced immunosuppression by in vivo administration of aminoguanidine hemisulfate (AG). AG was administered to C3HeB/FeJ mice in their drinking water (2.5% solution) for 7 days prior to intraperitoneal inoculation with SL3235. AG treatment inhibited the increase in nitrate and nitrite levels in plasma and nitrite levels in the spleen seen in immunized mice. Importantly, AG treatment completely blocked suppression of the splenic PFC response and markedly attenuated the suppression of the response to concanavalin A in immunized mice, providing further evidence thatSalmonella-induced immunosuppression is mediated by NO. AG treatment also alleviated the majority of the splenomegaly associated with SL3235 inoculation, which correlated with a blockage of influx of neutrophils and macrophages into spleens, as assessed by flow cytometry. AG treatment unexpectedly resulted in 90% mortality in mice injected with the highly attenuated vaccine strain ofSalmonella, SL3235. Increased mortality in AG-treated mice correlated with inability to clear organisms from the spleen by day 15 postinoculation and with persistent bacteremia, compared with control mice. Collectively, these in vivo results underscore the dual biological consequences of NO production followingSalmonella infection, with NO being necessary for host defense, but also having the potentially adverse effect of immunosuppression. A unifying hypothesis to explain how these seemingly paradoxical effects could both result from NO production is presented.

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Alabi, Okunola A. y Yetunde M. Adeoluwa. "Mutagenicity and genotoxicity of water boiled in aluminum pots of different duration of use using SOS chromotest and Ames fluctuation test". Toxicology Research 10, n.º 4 (1 de julio de 2021): 771–76. http://dx.doi.org/10.1093/toxres/tfab063.

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Abstract Boiling water before drinking or using it for cooking is a general practice especially in areas where portable water is not readily available. However, boiling water in an aluminum pot could be a route of entry of heavy metals into humans. This study assessed the genotoxic and mutagenic potential of boiled water samples from aluminum pots of different duration of use using the SOS chromotest on Escherichia coli PQ37 and the Ames fluctuation test on Salmonella typhimurium strains TA98 and TA100, respectively. Three aluminum pots from the same manufacturer but of different years of use (6-year-old, 3-year-old, and new aluminum pots) were used for the experiment. Six selected heavy metals (Cadmium, Copper, Arsenic, Nickel, Lead, and Aluminum) were also analyzed in the samples using an Atomic Absorption Spectrophotometer (AAS Buck, Scientific model 210 VGP). Cadmium, Copper, Arsenic, Nickel, Lead, and Aluminum were present in all the test water samples at concentrations that were higher than the maximum limit allowable by standard regulatory organizations. The concentrations of these metals in the samples also increased as the duration of use of the aluminum pots increased. The results further showed that the water boiled in the three aluminum pots is mutagenic and genotoxic in both Ames fluctuation and SOS chromotests. The 6-year-old aluminum pot induced the highest mutagenicity and genotoxicity followed by the 3-year-old aluminum pot. The metals in the tested samples were believed to be responsible for the observed mutagenicity and genotoxicity in the microbial assays. The findings of this study revealed that cooking with Aluminum pots could lead to the leaching of heavy metals into food, and pose mutagenic and genotoxic risks to consumers.

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KING, NICOLA, ROB LAKE y DONALD CAMPBELL. "Source Attribution of Nontyphoid Salmonellosis in New Zealand Using Outbreak Surveillance Data". Journal of Food Protection 74, n.º 3 (1 de marzo de 2011): 438–45. http://dx.doi.org/10.4315/0362-028x.jfp-10-323.

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In this study, 204 New Zealand outbreaks of nontyphoid salmonellosis reported from 2000 to 2009 were analyzed for information on the sources of human infection. Data were extracted from the outbreak module of EpiSurv, New Zealand's notifiable diseases database, and augmented with information from individual case reports and separate investigation reports. The outbreaks involved 1,426 cases, representing an estimated 9% of the total salmonellosis cases reported for the study period. Salmonella Typhimurium was the causative serotype in 78% of 172 outbreaks for which a serotype was available, involving 71% of outbreak cases. The most commonly reported outbreak setting was the home (47% of outbreaks), followed by commercial food operations (31%). Foodborne transmission was reported for 63% of the 123 outbreaks for which only one mode of transmission was reported, followed by person-to-person transmission (32%), waterborne transmission (3%), and zoonotic transmission (2%). However, evidence for the mode of transmission was weak or absent for 107 (63%) of the 169 outbreaks for which a mode of transmission was reported. For only 22 outbreaks was laboratory evidence successfully used to identify a potential source of infection. Of these 22 outbreaks, 7 were foodborne, 11 involved an infected food handler, 2 were attributed to contact with animals, 1 was attributed to consumption of drinking water, and 1 was attributed to multiple sources. The laboratory-confirmed contaminated foods were diverse and included imported and domestically produced foods. The results of this analysis support the hypothesis that nontyphoid salmonellosis is primarily a foodborne disease in New Zealand, but there is insufficient evidence to confirm important food vehicles.

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Кожевникова, Л. М., И. Ф. Суханова, А. В. Иванов y В. В. Александрин. "Hyperhomocysteinemia enhances the negative influence of Salmonella typhimurium LPS on vascular contractility and gene expression of receptor and regulatory proteins in rats". Nauchno-prakticheskii zhurnal «Patogenez», n.º 2 (28 de junio de 2021): 34–44. http://dx.doi.org/10.25557/2310-0435.2021.02.34-44.

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Наиболее тяжелым проявлением SARS-CoV-2 инфекции является развитие острого респираторного дистресс-синдрома. Высокий уровень гомоцистеина в крови пациентов - прогностически неблагоприятный фактор течения COVID-19 инфекции. Также развитие полиорганной недостаточности при COVID-19 инфекции часто утяжеляется эндотоксемией. Цель исследования. Изучение влияния гипергомоцистеинемии и липополисахарида (ЛПС) Salmonella Typhimurium на сократимость аорты и почечной артерии крыс и экспрессию генов рецепторных и регуляторных белков. Методикы. Моделирование гипергомоцистеинемии проводили путем добавления в воду L-метионина в концентрации 5 г/л (0,5%) в течение 14 дней. Эндотоксемию вызывали введением ЛПС Salmonella Typhimurium (Sigma, 5 мг/кг, в/б). Силу сокращения изолированных сосудов измеряли в изометрическом режиме. Экспрессию генов оценивали при помощи ПЦР-анализа. Результаты. Установлено, что через 24 часа после однократного введения животным ЛПС сила сокращения аорты возрастает в ответ на воздействие ангиотензина II (ATII, в 1,6 раза), аргнинвазопрессина (AVP, в 1,5 раза), и снижается после введения эндтелина-1 (ET-1, в 1,6 раза), по сравнению с аналогичными показателями контрольных крыс. При повторном введении ЛПС сосуды теряют чувствительность к вазоконстрикторам. У крыс после метиониновой нагрузки в плазме крови более чем в 3 раза повышается уровень общего гомоцистеина. Гомоцистеинемия приводит к выраженным нарушениям нейроэндокринной регуляции сократимости сосудов: снижается чувствительность аорты и почечной артерии к вазоконстрикторному действию ATII (в 1,7 и 2,6 раза соответственно), AVP (в 1,5 и 1,7 раза), серотонина (5HT, в 1,2 и 1,8 раза) и ET1 (в 1,5 и 1,6 раза). Установлено, что введение ЛПС крысам на фоне высокого уровня гомоцистеина в плазме ещё в большей степени усиливает выявленные нарушения сократительной активности сосудов. У крыс после введения ЛПС выявлен низкий уровень экспрессии вазоконстрикторных адренорецепторов α1A-AR, α1D-AR и вазодилататорных β1- и β2-адренорецепторов и высокий - ETA и ETB рецепторов. Как ЛПС, так и гипергомоцистеинемия приводят к значительному снижению содержания мРНК ангиотензинпревращающих ферментов ACE, ACE2 и рецепторов MasR, V1AR. У крыс после метиониновой нагрузки выявлено снижение экспрессии генов инозитолтрисфосфатных рецепторов IP3R2, IP3R3, что свидетельствует о нарушении кальциевого гомеостаза в сосудах. Метиониновая нагрузка не приводила к летальным исходам. В группе животных после однократного введения ЛПС смертность составляла 7%, а в группе с введением ЛПС после метиониновой нагрузки - 50%. Заключение. Таким образом, гипергомоцистеинемия усиливает ЛПС-индуцированные нарушения нейроэндокринной регуляции тонуса сосудов, отягощает течение и увеличивает смертность при эндотоксемии. The most severe manifestation of SARS-CoV-2 infection is the development of acute respiratory distress syndrome. A high blood level of homocysteine in patients is a prognostically unfavorable factor for the course of COVID-19 infection. The development of multiple organ failure in COVID-19 infection is aggravated by endotoxemia. The aim of the study was to investigate the effect of hyperhomocysteinemia and Salmonella Typhimurium lipopolysaccharide (LPS) on the rat aorta and renal artery contractility and the gene expression of receptor and regulatory proteins. Methods. Hyperhomocysteinemia was modeled in rats by adding L-methionine to drinking water at a concentration of 5 g/L (0.5%) for 14 days. Endotoxemia was induced with a single injection of Salmonella Typhimurium LPS (Sigma, 5 mg/kg, intraperitoneally). The contractile force of isolated blood vessels was measured in the isometric mode. Gene expression was assessed with the PCR analysis. Results. At 24 h after a single injection of LPS, the force of aortic contractile response to angiotensin II (ATII) increased 1.6 times and to arginine vasopressin (AVP) 1.5 times whereas the response to endothelin-1 (ET1) decreased by 37.5% compared to the respective values for control rats. Upon repeated administration of LPS, the blood vessels lost the sensitivity to vasoconstrictors. After methionine loading, the plasma level of total homocysteine increased more than three times. Homocysteinemia resulted in severe disorders in the neuroendocrine regulation of vascular contractility, including decreased sensitivity of the aorta and the renal artery to vasoconstrictor effects of ATII (41.2% and 61.5%, respectively), AVP (33.3% and 41.2%, respectively), serotonin (5HT, 16.7% and 44.4%, respectively) and ET1 (33.3% and 37.5%, respectively). The administration of LPS to rats on the background of a high plasma level of homocysteine further aggravated the disorders of vascular contractile activity. Administration of LPS was associated with lower expression of vasoconstrictor α1A- and α1D-adrenoceptors, and of vasodilator β1- and β2-adrenoceptors and with a higher expression of ETA and ETB receptors. Both LPS and hyperhomocysteinemia led to significant decreases in angiotensin-converting enzymes ACE and ACE2 mRNA, and in MasR and V1AR receptor mRNA. The methionine loading induced a decrease in the gene expression of inositol trisphosphate receptors IP3R2 and IP3R3, which indicated a disorder of calcium homeostasis in the blood vessels. The methionine loading was not fatal. In the group of animals after a single administration of LPS, the mortality rate was 7%, and in the group after the administration of LPS and methionine loading, the mortality rate was 50%. Conclusion. Thus, hyperhomocysteinemia enhances LPS-induced disorders in the neuroendocrine regulation of vascular tone, aggravates the course of endotoxemia, and increases the mortality rate.

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Suci, Dwi Margi, N. U. Nuha y Suryahadi Suryahadi. "Pemberian Ekstrak Daun Kemuning (Murraya paniculata (L.) Jack) dalam Air Minum terhadap Performa dan Kualitas Fisik Telur Puyuh Malon". Jurnal Ilmu Nutrisi dan Teknologi Pakan 17, n.º 3 (30 de diciembre de 2019): 73–77. http://dx.doi.org/10.29244/jintp.17.3.73-77.

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The aim of this study was to determine the effect of kemuning leaves (Murraya paniculata (L.) Jack) extract supplementation of the drinking water on performance and physical quality of egg. Twenty-four weeks old of malon hybrid quails which amounts to 240 birds were allocated in a Completely Randomized Design with four treatments and two replications. The treatments were namely P0 = control (without kemuning leaves extrct), and added kemuning leaves extract into drinking water (4 consecutive days per weeks) with dose of 3% (P1), 5% (P2) and 7% (P3). The commercial diet used in this study contained 20.01 % of crude protein. The results showed that supplementation of 3% and 7% of kemuning leaves extract into drinking water had no significant difference on performance and physical quality of egg. It was concluded that the dose of 5% kemuning leaf extract addition into total drinking water tends to produce the highest egg production (85%). Key words: Murraya paniculata (L.) Jack, performance malon quail, egg physical quality DAFTAR PUSTAKA Andari, A, Anisa EN, Wulandari RF & Suci DM. 2018. Efek suplementasi jamu rempah pada puyuh (Coturnix coturnix japonica) terhadap performa dan kadar kolesterol telur. Jurnal Ilmu Nutrisi dan Teknologi Pakan 16 (2): 34-41 Adfa, M.2007. Isolasi senyawa flavonoid aktif berkhasiat sitotoksik dari daun kemuning (Murraya paniculata L.Jack). Jurnal Gradien 3(2): 262-266 Halimah, H, Suci, DM &Wijayanti I.2019. Studi potensi penggunaan daun mengkudu (Morinda citrifolia L.) sebagi bahan antibakteri Escherichia coli dan Salmonella typhimurium. Jurnal Ilmu Pertanian Indonesia 24 (1): 56-64 Hanusova E, Hrnčár C, Hanus A, & Oravcová M. 2016. Egg traits in Japanese quail. Acta Fytotechnica et Zootechnica 19 (Special Issue) : 62-67 Hilmi,M, Sumiati & Astuti DA. 2015. Egg production and physical quality in Coturnix-coturnix Japonica fed diet containing piperine as phytogenic feed additive. Media Peternakan 38 (3): 150-155 Hrnčár C, Hanusová E, Hanus A & Bujko J. 2014. Effect of genotype on egg quality characteristic of Japanese quail (Coturnix Japonica). Slovak Journal of Animal Science 47(1): 6-11. Iskender H, Yenice G, Dokumacioglu E, Kaynar O, Hayirli A, & Kaya A. 2016. The effect of dietary flavonoid supplementation on the antioxidant status of laying hens. Brazilian Journal of Poultry Science. 18 (4): 663-668 Nowaczewski S, Kontecka H, Rosiñski A, & Koronowsk SBP. 2010. Egg quality of Japanese quail depends on layer age and storage time. Folia biologica (Kraków) 58(3-4): 201-207 Nugroho, AE, Riyanto S, Sukari MA, Maeyama K. 2010. Efek senyawa flavonoid dari kemuning (Murraya paniculata [L.] Jack terhadap pelepasan histamin dari kultur sel mast. Majalah Obat Tradisional 15 (1): 34-40 Parubak A S, 2013. Senyawa flavonoid yang bersifat antibakteri dari Akway (Drimys becariana Gibbs). Chemistry Progress 6 (1): 34-37 Prajonggo TS, DjatmikoW & Soemarno. 1983. Pengaruh Sauropus androgynus L. Merr terhadap gambaran hisotologi kelenjar susu mencit betina yang menyusui. Prosiding Kongres Nasional XI FSI. Jakarta (ID): Hlm 735-739. Saerang LP, Josephine, Yuwanta T & Nasroedin. 2000. Pengaruh minyak nabati dan lemak hewani dalam ransum puyuh petelur terhadap performa daya tetas, kadar kolesterol dan plasma darah. Buletin Peternakan 22(2):96-101 Setyaningrum S & Siregar DJS. 2015. Efektivitas minuman herbal terhadap pertumbuhan puyuh. Surya Agritama. 4:1:109-117 Siregar B. 2008. Pengaruh penambahan tepung daun singkong (Manihot utilisima crantz) dalam pakan terhadap performans produksi telur puyuh (Cortunix-cortunix japonica) petelur. Jurnal Ilmiah Ilmu-Ilmu Peternakan 11(1):28-33. Song KT, Choi SH, & Oh HR. 2000. A comparison og egg quality of pheasant, chukar, quail, and guinea fowl. Asian Australasian Journal Animal Science 13 (70): 986-990 Stojčić MD, Milošević N, Perić L, Jajić I, & Tolimir N. 2012. Egg Quality of Japanese quail in Serbia. Biotechnology in Animal Husbandry 28(3): 425-431 Subekti, S. 2007. Senyawa fitosterol dalam daun katuk (Sauropus androgynous L. Merr) dan pengaruhnya pada fungsi reproduksi puyuh. [disertasi]. Sekolah Pascasarjana: Institut Pertanian Bogor Sultana F, Islam MS & Howlider MAR. 2007. Effect of dietary Calcium sources and levels on egg production and egg shell quality of Japanese quail. International Journal of Poultry Science 6 (2): 131-136 Zainuddin D & Wibawan IWT. 2007. Biosekuriti dan Manajemen Penanganan Penyakit Ayam Lokal. Dwiyanto K, Prijono ST, editor. Bogor (ID): Pusat Penelitian Biologi LIPI. Zita L, Ledvinka Z & Klesalova L. 2013. The effect of the age of Japanese quails on certain egg quality traits and their relationships. Veterinarski Archive 83 (2) : 223-232. Yilmaz, A, Tepeli C & Çağlayan T. 2011. External and internal quality characteristics in Japanese quails of different plumage color lines. Journal of Food Agriculture and Environment 9 (2): 375-379 Yuhernita & Juniarti. 2011. Analisis senyawa metabolit sekunder dari ekstrak methanol daun Surian yang berpotensi sebagai antioksidan. Makara Sains 15(1): 48-52

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Skowroń, Jolanta y Katarzyna Konieczko. "Hydrogen cynide and cyanide salts: sodium, potassium, calcium, as CN-. Documentation of proposed values of occupational exposure limits (OELs)". Podstawy i Metody Oceny Środowiska Pracy 33, n.º 1(91) (30 de marzo de 2017): 5–62. http://dx.doi.org/10.5604/1231868x.1232633.

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Hydrogen cyanide (HCN) and its salts: potassium cyanide (KCN), sodium cyanide (NaCN) and calcium cyanide [Ca(CN2)] are very toxic. Hydrogen cyanide at ambient conditions is a colourless liquid or a colourless gas with the characteristic odour of bitter almonds. Sodium, potassium and calcium cyanides are white hygroscopic, crystalline solids with a slight HCN odour. Hydrogen cyanide is used mainly in a fumigation of ships, buildings, orchards and various foods, in electroplating, in the production of chelating agents such as EDTA, and in metal treatment processes. It is also used as a chemical intermediate. Cyanides are used in the extraction and recovery of gold and silver from ores, the heat treatment of metals, and electroplating. They are also precursors in chemical syntheses. Workers from metal, electrochemical, plastics, pharmaceutical, textile, chemical and food industries are exposed to these compounds. In 2008–2013, there were no workers exposed to the concentration of hydrogen cyanide and sodium, potassium and calcium cyanides exceeding the maximum admissible ceiling concentration MAC(C) 5 mg/m3 (the national database maintained by the Regional Sanitary Station in Bydgoszcz). Hydrogen cyanide and cyanides are irritating to mucous membranes and skin. They are absorbed by inhalation, dermal and oral exposure. The acute hydrogen cyanide and cyanides poisoning indicate a great danger and hazard, because these compounds are quickly absorbed into the body and their effects are present within a few minutes after the start of exposure. Exposure to sodium cyanide at a concentration of 286 mg/m3 or to hydrogen cyanide at a concentration greater than 300 mg/m3 for 1 min may be fatal. Sodium, potassium or calcium cyanides at concentrations of 25 mg/m3 are direct hazards to life and health of workers if exposure lasts about 30 min and without respiratory protection. For hydrogen cyanide this value was established as 56 mg/m3. The development of symptoms of acute poisoning by hydrogen cyanide or cyanides in humans occurs in three phases: breathlessness and excitement, convulsions and paralysis. The results of studies of subchronic and chronic exposures of workers to cyanides by inhalation indicate that symptoms of exposure were associated with changes in the central nervous system (headache, weakness, changes in the sensation of taste and smell) and damage to the thyroid (enlargement, changes in uptake of iodine, elevated concentration of thyroid stimulating hormone TSH and a reduction of thyroid hormones T3 and T4). Other studies suggest that chronic exposure to hydrogen cyanide in the hardening plant of metals caused decrements in lung functions among workers. Hydrogen cyanide and cyanides, both in aqueous solution, applied to the conjunctival sac or on the skin is quickly absorbed into the body of animals in amounts sufficient to cause toxic effects and death. In rats and mice treated with sodium cyanide in drinking water at a dose of 4.5 mg/kg bw/day for 13 weeks, no significant changes in biochemical and haematological parameters of peripheral blood and histopathological findings in the internal organs were observed. There were no pathological changes in the respiratory, cardiovascular, nervous system and kidneys in rats which were feed with hydrogen cyanide over two years. Calculated NOAEL was approximately 10.4 mg/kg body weight. There is no available data on the carcinogenicity of hydrogen cyanide and cyanides in human and animals. Positive effects were obtained in one study only, in which hydrogen cyanide was tested with Salmonella typhimurium strain TA 100 in the absence of metabolic activation, while the other strains employed in this study yielded negative results. Cyanides did not show mutagenic activity in the tests in vitro and in vivo. On the basis of the studies on hamsters, teratogenic effects of sodium cyanide were observed. This compound was toxic for pregnant mothers and caused an increase in fatal resorption and malformations in an offspring. The results of the study of workers exposed to hydrogen cyanide and cyanides and with changes in thyroid were the basis for calculating MAC (NDS) value. The LOAEL value was establishes as a concentration of 4.7 mg/m3. The MAC of 1 mg/m3 (calculated CN–) was established for hydrogen cyanide and the inhalable fraction of sodium, potassium, calcium cyanides was accepted. Due to totally different mechanism of action of hydrogen cyanide and cyanides (sodium, potassium, calcium) in chronic exposure (effects on the thyroid gland) and in the acute exposure, which is primarily associated with inhibition enzymatic system of cytochrome c oxidase, which prevents cells from using oxygen (histotoxic hypoxia), for these compounds the ceiling value MAC(C) of 5 mg/m3 was not changed. Such an approach is a deviation from the basic methodology adopted by the Group of Expert and the Interdepartmental Commission for MAC and MAI. MAC and ceiling MAC(C) values for these substances should be establish due to the different effects of critical action and mechanisms of action in the acute and chronic condition. This approach is consistent with the DECOS Committee (Dutch Expert Committee on Occupational Standards) from 2002. According to the committee, the acute human data show the most sensitive effect, i.e., death. The steepness of the dose-response relationship and the severity of the acute effects in humans imply at the same time that utmost care should be taken to prevent this exposure level from being exceeded, not even for a short time. Therefore, the committee proposed to establish a ceiling value for the acute health effects of 10 mg/m3 for hydrogen cyanide. The Scientific Committee on Occupational Exposure Limit Values (SCOEL) proposed an OEL value of 1 mg/m3. However, since the acute effects in humans are severe (i.e., death) and show a rather steep dose-response relationship, peak exposures should be avoided. Based on the steepness of the dose-response relationship and the severity of the acute effects in humans a STEL of 5 mg/m3 is recommended as CN– from any combination of the three compounds. Based on the very high skin permeability measured for hydrogen cyanide and cyanide anions in aqueous solutions, a skin notation is recommended for hydrogen cyanide and sodium, potassium, calcium cyanides.

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Chen, Jiang, Ya Shi, Dongqing Cheng, Yan Jin, William Hutchins y Jingqing Liu. "Survey of pathogenic bacteria of biofilms in a metropolitan drinking water distribution system". FEMS Microbiology Letters, 7 de noviembre de 2019. http://dx.doi.org/10.1093/femsle/fnz225.

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Abstract Bacteria, especially pathogenic bacteria, were detected in order to estimate the safety of drinking water distribution systems (DWDS). 16 biofilms and 12 water samples (6 retained and 6 flowing) were collected from a city DWDS in Eastern China. Biofilms were observed using scanning electron microscopy. Cultivable bacteria of biofilms were counted by heterotrophic plate counts, ranging from 3.61 × 101 to 1.67 × 106 CFU·cm−2. Coliforms, Salmonella, Shigella, Vibrio, and Legionella were separated by EMB agar, Salmonella chromogenic medium, Shigella chromogenic medium, TCBS agar, BCYE agar, and 13/16, 8/16, 7/16, 6/16, 0/16 biofilm samples were found positive respectively. Retained and flowing water samples were collected to estimate the influence of hydrodynamic conditions on biofilm detachment. All 6 retained water samples were positive for bacteria, count ranged from 1.2 × 103 to 2.8 × 104 CFU·mL−1 and 2/6, 3/6, 2/6, 0/6, 0/6 samples were positive for coliforms, Salmonella, Shigella, Legionella, and Vibrio, respectively. While only 3 of 6 flowing water samples were bacteria positive, counts ranged from 102 to 103 CFU·mL−1, 2/6 were coliforms positive, no pathogens under testing were detected. The results show that there are pathogens in DWDS biofilms, which can cause health related problems if detached from their surface.

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Salvucci, Anthony, Wei Zhang, Veronica Morales, M. Cakmak, Anthony Hay y Tammo Steenhuis. "The impact of biofilm-forming potential and tafi production on transport of environmental Salmonella through unsaturated porous media". Biologia 64, n.º 3 (1 de enero de 2009). http://dx.doi.org/10.2478/s11756-009-0102-y.

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AbstractUnderstanding the factors influencing the transport of microbial pathogens, such as Salmonella and Escherichia coli, through porous media is critical to protecting drinking water supplies. The production of biofilms, along with individual biofilm-associated components, such as tafi, is believed to hinder transport of microorganisms through soil. This study investigated the relationship between biofilm formation and tafi production and the transport of environmental Salmonella through porous media. Thirty-two Salmonella isolates were initially assayed for their ability to form biofilms, from which a subset of these was selected to represent a range of high and low biofilm-formation potential and tafi formation capabilities. These were subsequently examined in unsaturated sand columns for transport characteristics. No obvious correlation was observed between Salmonella phenotypes and column retention. The results indicated that while transport of well-characterized laboratory E. coli strains can often be hindered by the presence of tafi and the potential to form biofilms, the presence of tafi did not retard the transport of the Salmonella strains.

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Abdelmalek, Shaymaa, Mona Kadry, Esraa A. Elshafiee, Wafy Hamed, Ihab Mohamed Moussa, Khalid S. Al-Maary, Ayman S. Mubarak, Hassan A. Hemeg y Ayman Elbehiry. "Occurrence of Salmonella infection and antimicrobial susceptibility for local Salmonella isolates from different sources in a cross-sectional study". Italian Journal of Food Safety 8, n.º 4 (5 de diciembre de 2019). http://dx.doi.org/10.4081/ijfs.2019.8525.

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Salmonellosis is a considerable public health problem worldwide, with high economic importance in developed countries. The main purpose of this study was to determine the prevalence of Salmonella infection and antibiogram analysis of isolated strains in a cross-sectional study in Egypt 2016-2017. The study investigated twenty-eight Salmonella isolates from different areas in Egypt and different types of samples, such as human stool (9.3%), Egyptian cattle egrets and storks (28.5%) and grilled chicken from electric grills (36.6%). No isolates were detected from grilled chicken from charcoal grills or drinking water. The main Salmonella serotype detected in the isolates was S. typhimurium (86.5%). Molecular characterization of the invA gene by PCR was carried out and then confirmed by sequencing, and the results were submitted to GenBank. Antibiogram analysis of Egyptian isolates carried out on 9 antimicrobial discs reported that the routine regimes of treatment were not yet effective for recent new Salmonella generations in 2016-2017. The new isolates could be treated with levofloxacin, cefaperazone/sulbactam, chloramphenicol, imipenem or meropenem.

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Maes, Sharon, Koen De Reu, Stephanie Van Weyenberg, Bram Lories, Marc Heyndrickx y Hans Steenackers. "Pseudomonas putida as a potential biocontrol agent against Salmonella Java biofilm formation in the drinking water system of broiler houses". BMC Microbiology 20, n.º 1 (diciembre de 2020). http://dx.doi.org/10.1186/s12866-020-02046-5.

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Abstract Background Environmental biofilms can induce attachment and protection of other microorganisms including pathogens, but can also prevent them from invasion and colonization. This opens the possibility for so-called biocontrol strategies, wherein microorganisms are applied to control the presence of other microbes. The potential for both positive and negative interactions between microbes, however, raises the need for in depth characterization of the sociobiology of candidate biocontrol agents (BCAs). The inside of the drinking water system (DWS) of broiler houses is an interesting niche to apply BCAs, because contamination of these systems with pathogens plays an important role in the infection of broiler chickens and consequently humans. In this study, Pseudomonas putida, which is part of the natural microbiota in the DWS of broiler houses, was evaluated as BCA against the broiler pathogen Salmonella Java. Results To study the interaction between these species, an in vitro model was developed simulating biofilm formation in the drinking water system of broilers. Dual-species biofilms of P. putida strains P1, P2, and P3 with S. Java were characterized by competitive interactions, independent of P. putida strain, S. Java inoculum density and application order. When equal inocula of S. Java and P. putida strains P1 or P3 were simultaneously applied, the interaction was characterized by mutual inhibition, whereas P. putida strain P2 showed an exploitation of S. Java. Lowering the inoculum density of S. Java changed the interaction with P. putida strain P3 also into an exploitation of S. Java. A further increase in S. Java inhibition was established by P. putida strain P3 forming a mature biofilm before applying S. Java. Conclusions This study provides the first results showing the potential of P. putida as BCA against S. Java in the broiler environment. Future work should include more complex microbial communities residing in the DWS, additional Salmonella strains as well as chemicals typically used to clean and disinfect the system.

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Soliman, Essam S., Rania T. Hamad y Rania A. Hassan. "Moderations in performance, immunity, tissue architecture, and vaccine viability induced by water magnetization in broiler farms". Veterinary World, 30 de junio de 2021, 1695–710. http://dx.doi.org/10.14202/vetworld.2021.1695-1710.

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Background and Aim: Water magnetization contributes to increased molecular ionization and fluidity, which improves biological activities. This study tests the influence of magnetic water on the viability of the Newcastle vaccine and the survival of Escherichia coli and Salmonella Typhimurium, as well as the influence of magnetic water in face of water impurities' challenges on performance, immunity, and tissue architecture in broiler chickens. Materials and Methods: An in vitro 96-micro-well plate minimal inhibitory concentration was utilized to test the influence of water, saline, and magnetic water on Newcastle vaccine viability and E. coli O157:H7 and S. Typhimurium survival. The 245 experimental 1-day-old female Ross® 308 broilers used in this study were divided into seven groups of 35 birds each. Broilers were provided with magnetic drinking water (13,200 gausses) for 6 h daily from the 5th day and were challenged on days 14, 21, 28, and 35 using sodium chloride (700 mg/L), calcium sulfate (80 mg/L), lead acetate (500 mg/L), yeast extract 5% (5 mg/L), diazinon (2.5 mL/L), and E. coli O157:H7 (1.6 × 109 CFU/mL). A total of 2040 samples (96 diluent-Newcastle virus vaccine mixes, 96 microbial-magnetic water mixes, 231 sera, 231 intestinal swabs, and 1386 organ samples) were collected. Results: An in vitro trial revealed highly significant (p<0.01) declines of 94.13%, 84.53%, and 10.31% in the Newcastle vaccine titer in water, saline, and magnetic water, respectively, and 54.91% and 39.89% in E. coli O157:H7 and S. Typhimurium survival, respectively, after 4 h. In all challenged groups, broilers exhibited highly significant (p<0.01) increases in performance, carcass/organs weight, immunoglobulin G, immunoglobulin M, and Lactobacillus counts; significant improvement in tissue architecture and biochemical parameters; and highly significant (p<0.01) reductions in cortisol, superoxide dismutase, and total bacterial and Enterobacteriaceae counts. Conclusion: Magnetic water could maintain vaccine viability and vaccination efficiency, reduce microbial survival, and minimize the negative influence of all induced challenges.

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Bonassa, Karina P. D., Miwa Y. Miragliotta, Rosineide C. Simas, Marcos N. Eberlin, Arturo Anadón, Ronilson A. Moreno y Felix G. R. Reyes. "Pharmacokinetics, Pharmacodynamic Efficacy Prediction Indexes and Monte Carlo Simulations of Enrofloxacin Hydrochloride Against Bacterial Strains That Induce Common Clinical Diseases in Broiler Chickens". Frontiers in Veterinary Science 7 (7 de enero de 2021). http://dx.doi.org/10.3389/fvets.2020.606872.

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Pharmacokinetic parameters and efficacy prediction indexes (Cmax/MIC90 and AUC0−24/MIC90) of an enrofloxacin hydrochloride (ENR-HCl) veterinary product soluble in water were determined in healthy broiler chickens of both sexes after a single oral dose of ENR-HCl (equivalent to 10 mg ENR base/kg bw). Monte Carlo simulations targeting Cmax/MIC90 = 10 and AUC0−24/MIC90 =125 were also performed based on a set of MIC (minimum inhibitory concentration) values of bacterial strains that induce common clinical diseases in broiler chickens and that showed to be susceptible to ENR-HCl. Plasma concentrations of ENR and its main metabolite ciprofloxacin (CIP) were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Plasma concentration-time curves were found to fit a non-compartmental open model. The ratio of the area under the plasma concentration-time curve (AUC) of CIP/ENR was 4.91%. Maximum plasma concentrations of 1.35 ± 0.15 μg/mL for ENR-HCl and 0.09 ± 0.01 μg/mL for CIP were reached at 4.00 ± 0.00 h and 3.44 ± 1.01 h, respectively. Areas under the plasma vs. time concentration curve in 24 h (AUC0−24) were 18.91 ± 1.91 h × μg/mL and 1.19 ± 0.12 h × μg/mL for ENR-HCl and CIP, respectively. Using a microbroth dilution method, the minimum inhibitory concentration (MIC90) values were determined for ENR-HCl for 10 bacterial strains (Mycoplasma gallisepticum, Mycoplasma synoviae, Avibacterium paragallinarum, Clostridium perfringens, Escherichia coli, Pseudomonas aeruginosa, Salmonella ser. Enteritidis, Salmonella ser. Gallinarum, Salmonella ser. Pullorum, and Salmonella ser. Typhimurium), which are the most common causes of infectious clinical diseases in broiler chickens. In summary, the PK/PD ratios and Monte Carlo simulation were carried out for ENR-HCl in poultry, which due to its solubility was administered in drinking water. The PK/PD efficacy prediction indexes and Monte Carlo simulations indicated that the ENR-HCl oral dose used in this study is useful for bacterial infections in treating C. perfringens (Gram-positive), E. coli and S. ser. Enteritidis (Gram-negative) and M. gallisepticum bacteria responsible for systemic infections in poultry, predicting a success rate of 100% when MIC ≤ 0.06 μg/mL for E. coli and S. ser. Enteritidis and MIC ≤ 0.1 μg/mL for M. gallisepticum. For C. perfringens, the success rate was 98.26% for MIC ≤ 0.12. However, clinical trials are needed to confirm this recommendation.

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50

Motlhatlego, Katlego E., Muna Ali Abdalla, Carmen M. Leonard, Jacobus N. Eloff y Lyndy J. McGaw. "Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation". BMC Complementary Medicine and Therapies 20, n.º 1 (23 de noviembre de 2020). http://dx.doi.org/10.1186/s12906-020-03139-4.

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Abstract Background Diarrhoea is a major health issue in both humans and animals and may be caused by bacterial, viral and fungal infections. Previous studies highlighted excellent activity of Newtonia buchananii and N. hildebrandtii leaf extracts against bacterial and fungal organisms related to diarrhoea-causing pathogens. The aim of this study was to isolate the compound(s) responsible for antimicrobial activity and to investigate efficacy of the extracts and purified compound against bacterial biofilms. Methods The acetone extract of N. buchananii leaf powder was separated by solvent-solvent partitioning into eight fractions, followed by bioassay-guided fractionation for isolation of antimicrobial compounds. Antibacterial activity testing was performed using a broth microdilution assay. The cytotoxicity was evaluated against Vero cells using a colorimetric MTT assay. A crystal violet method was employed to test the inhibitory effect of acetone, methanol: dichloromethane and water (cold and hot) extracts of N. buchananii and N. hildebrandtii leaves and the purified compound on biofilm formation of Pseudomonas aeruginosa, Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus. Results Myricetin-3-o-rhamnoside (myricitrin) was isolated for the first time from N. buchananii. Myricitrin was active against B. cereus, E. coli and S. aureus (MIC = 62.5 μg/ml in all cases). Additionally, myricitrin had relatively low cytotoxicity with IC50 = 104 μg/ml. Extracts of both plant species had stronger biofilm inhibitory activity against Gram-positive than Gram-negative bacteria. The most sensitive bacterial strains were E. faecalis and S. aureus. The cold and hot water leaf extracts of N. buchananii had antibacterial activity and were relatively non-cytotoxic with selectivity index values of 1.98–11.44. Conclusions The purified compound, myricitrin, contributed to the activity of N. buchananii but it is likely that synergistic effects play a role in the antibacterial and antibiofilm efficacy of the plant extract. The cold and hot water leaf extracts of N. buchananii may be developed as potential antibacterial and antibiofilm agents in the natural treatment of gastrointestinal disorders including diarrhoea in both human and veterinary medicine.

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