Bibliografías temáticas / Drinking water Salmonella typhimurium. Biofilms

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Literatura académica sobre el tema "Drinking water Salmonella typhimurium. Biofilms"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 13 de febrero de 2022

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Artículos de revistas sobre el tema "Drinking water Salmonella typhimurium. Biofilms"

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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Tesis sobre el tema "Drinking water Salmonella typhimurium. Biofilms"

Burke, Lisa Mandy. "Fate of Salmonella Typhimurium in biofilms of drinking water distribution systems". Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-02232007-192747.

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Actas de conferencias sobre el tema "Drinking water Salmonella typhimurium. Biofilms"

Steichen, Quynn, Rex Smiley, Brian Fergen, Dianna Jordan, Kelly Lechtenberg, Troy Kaiser, Jessica Seate y Petra Maass. "Salmonella typhimurium fecal shedding following Salmonella choleraesuis-thyphimurium vaccination via drinking water and subsequent challenge". En Safe Pork 2015: Epidemiology and control of hazards in pork production chain. Iowa State University, Digital Press, 2017. http://dx.doi.org/10.31274/safepork-180809-354.

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Augustine, Shancy, Pan Gu, Xiangjun Zheng, Toshikazu Nishida y Z. Hugh Fan. "Development of All-Plastic Microvalve Array for Multiplexed Immunoassay". En ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38154.

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There is a need for low-cost immunoassays that measure the presence and concentration of multiple harmful agents in one device. Currently, comparable immunoassays employ a one-analyte-per-test format that is time consuming and not cost effective for the requirement of detecting multiple analytes in a single sample. For instance, if a spectrum of harmful agents, including E. coli O157, cholera toxin, and Salmonella typhimurium, should be simultaneously monitored in foods and drinking water, then a one-analyte-per-test would be inefficient. This work demonstrates a platform capable of simultaneous detection of multiple analytes in a single, low-cost, microvalve array-enabled multiplexed immunoassay. This multiplexed immunoassay platform is demonstrated in a prototype COC (cyclic olefin copolymer) device with a 2×3 array in which 6 analytes can be detected simultaneously. In order to contain and regulate the flow of reagents in the multichannel device, an array of microfluidic valves actuated by a thermally expandable material and microfabricated resistors have been developed to direct the flow to the necessary assay sites. The microvalve-based immunoassay is shown to be reliable, easy to operate, and compatible with large-scale integration. The all-plastic microvalves use paraffin wax as the thermally sensitive material which drastically reduces power consumption by latching upon closing so that pulsed power is required only to close and latch the microvalve until it is necessary to re-open the valve. The multiplexed detection scheme has been demonstrated by using three proteins, C reactive protein (CRP) and transferrin, both of which are biomarkers associated with traumatic brain injury (TBI) as well as bovine serum albumin (BSA) as the negative control. Since there are no external bulky pneumatic accessories required to operate/latch the microvalves in the device, this compact, thermally actuated and latching microvalve-enabled multiplexed immunoassay has the potential to realize a portable, low power, battery operated microfluidic device for biological assays.

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