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Ho, Macy, Elizabeth R. Armstrong, Christopher J. Graber, et al. "1011. Hospital Antibiogram Variation within a Veterans Affairs (VA) Regional Network." Open Forum Infectious Diseases 6, Supplement_2 (2019): S355—S356. http://dx.doi.org/10.1093/ofid/ofz360.875.
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Abstract Background VISN 22 is comprised of eight VA hospitals serving Southern California, Arizona, and New Mexico. The VISN 22 Antimicrobial Stewardship Workgroup formed in November 2018 with the purpose of sharing strong practices and program strategies. We compared antibiogram compilation strategies and antimicrobial susceptibilities and correlated antimicrobial susceptibilities for Pseudomonas aeruginosa and Escherichia coli with inpatient and outpatient antibiotic use. Methods 2018 antibiograms were collected from each hospital. Antibiotic utilization rates (antibiotic days per 1000 patient-days present) were extracted from VA Corporate Data Warehouse data. Pearson correlation coefficients were calculated between 2018 utilization of specific agents and P. aeruginosa and E. coli susceptibilities to those agents at each facility. Results Antibiograms varied according to authorship (microbiology and/or infectious diseases), reporting frequency, rules regarding isolate reporting, and location and specimen specificity (Table 1). Facilities reported at least 90% susceptibility to a median of 3 antibiotics (range 1 to 5) for P. aeruginosa and 5 antibiotics (range 1 to 7) for E. coli. The strongest negative correlations between antimicrobial use and susceptibility were observed for meropenem/imipenem (-0.43) and piperacillin–tazobactam (-0.41) with P. aeruginosa and piperacillin–tazobactam (-0.23) and fluoroquinolones (-0.21) with E. coli. A moderate negative correlation was observed between outpatient fluoroquinolone prescriptions per 1000 patients and E. coli susceptibility (-0.24). Conclusion Antibiogram composition is variable across VISN 22; not all reporting is consistent with CLSI recommendations. There was a modest correlation between some categories of antimicrobial use and resistance in P. aeruginosa and E. coli. Sharing antibiogram and antibiotic utilization data are helpful in developing antimicrobial stewardship strategies especially as we examine those hospitals with lower rates of resistance and antibiotic use. Disclosures All authors: No reported disclosures.
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Bao Tran, Pham, Nguyen Anh Thu, and Tong Thi Hang. "Effect of commercial probiotics and antibiotics on the growth of Campylobacter isolated from chicken meat in Ho Chi Minh city markets." Vietnam Journal of Biotechnology 21, no. 3 (2024): 549–63. http://dx.doi.org/10.15625/1811-4989/19755.
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This study explores the antibiotic susceptibility of Campylobacter, a prominent foodborne pathogen, isolated in Ho Chi Minh city markets and the efficacy of commercial probiotics in inhibiting these bacteria for enhancing food safety and treating Campylobacter infections. Bacteria were isolated from chicken meat in modified coal deoxycholate cefoperazone agar (mCCD), followed by characterization as per standard procedures. Ten isolates with Gram negative, catalase positive and oxidase positive characteristics were collected. Antibiotic susceptibility is ascertained through the determination of the inhibited zone and minimum inhibitory concentration (MIC) of five distinct antibiotics against Campylobacter on Muller Hinton agar plates, culminating in a comprehensive assessment after a 24-hour incubation duration. The antibiotic susceptibility results underscore substantial diversity in Campylobacter isolates among meat samples, thereby accentuating discernible distinctions among the various antibiotic products. The research also evaluated the suitability of 5 commercial probiotic products (re-named as A, B, C, D, and E for fair assessment) by examining their impact on the growth of Campylobacter colonies. The antimicrobial effect of probiotics against Campylobacter is assessed using the agar well diffusion assay and co-culture method. We obtained consistent results from two methods, indicating no variation in Campylobacter species among meat samples but significant variations among probiotic products. The outcomes of this research provide valuable insights into the antimicrobial potential of each probiotic and antibiotic on Campylobacter, informing recommendations for food hygiene practices and underscoring the role of both probiotics and antibiotics in combating Campylobacter infections.
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Mwanzo Wavindu, Edith B. Mouafo Tamnou, Ildephonse Soly Kamwira, et al. "Susceptibility of some Enterobacteriaceae isolated from 4 different aquatic environments in DR Congo (Central Africa), to Amoxicillin/Clavulanic acid and some 3rd generation Cephalosporins." GSC Biological and Pharmaceutical Sciences 26, no. 1 (2024): 178–90. http://dx.doi.org/10.30574/gscbps.2024.26.1.0002.
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Little is known about the variation of the antibiotic susceptibility of different bacterial strains of the same cells species, isolated from different aquatic environments. The present study aims to evaluate the susceptibility towards some 3rd generation cephalosporins (Ceftriaxon, Ceftazidim and Cefotaxim) and Amoxicillin/Clavulanic acid, of Enterobacteriaceae strains isolated from groundwater, stream, hospital wastewater and slaughterhouse wastewater. Enterobacteria species were isolated on Mac Conkey agar, then identified using enzymatic and MALDI-TOF MS system. The antimicrobial susceptibility was carried out using the disk diffusion method. The antibiotic minimum inhibitory concentrations (MICs) were carried using the VITEK®2 system. Bacterial species mostly identified were Klebsiella pneumoniae, Escherichia coli, Salmonella typhi and Ewingelia americana. The antibiotic inhibition diameters and the MICs varied depending on the antibiotics, bacterial species and type of aquatic environment hosting the microorganism. Relatively lower MICs were recorded with Cefotaxim against different bacteria in slaughterhouse wastewater, in river water and in well water. Antibiotic resistance was noted with all strains from hospital wastewater. Significant differences (P˂0.05) amongst antibiotic inhibition diameter was noted for K. pneumoniae and S. typhi in most cases. The relative variations in the action mechanisms amongst antibiotics and the intrinsic defense potential of each bacterial strain, as well as the potential influence of the physicochemical properties of each water medium, could partly be at the origin of the relative differences observed at the phenotypic level. It seems necessary to explore the diversity, similarities and differences amongst antibiotic resistance genes in these different types of aquatic biotopes.
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Habibah, Firda Nurul, Hafizah Ilmi Sufa, Iis Kurniati, and Zuri Rismiarti. "Effect of solvent variation on results of antibiotic susceptibility test using the disk diffusion method against Staphylococcus aureus." Current Biomedicine 3, no. 2 (2025): 60–66. https://doi.org/10.29244/currbiomed.3.2.60.
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Background Mueller-Hinton agar (MHA) is widely used for disk diffusion tests to assess antibiotic susceptibility in non-fastidious bacteria. The type of water used to prepare the MHA may have affected the test outcomes. Objective This study evaluated the effect of different water types as solvents on the antibiotic susceptibility test results of tetracycline and gentamicin against Staphylococcus aureus. Methods MHA was prepared using four types of water: distilled (control), bottled, reverse osmosis (RO), and municipal tap water (PDAM). Antibiotic susceptibility testing was performed using the Kirby-Bauer disk diffusion method, and data were analyzed using One-Way ANOVA and Tukey’s Post Hoc test. Results The mean inhibition zones for tetracycline were 23.8 ± 0.99 mm (distilled), 23.4 ± 0.37 mm (bottled), 23.0 ± 0.43 mm (RO), and 17.8 ± 1.41 mm (tap), categorized as sensitive except for tap water (intermediate). For gentamicin, the zones were 11.7 ± 0.37 mm (distilled), 12.7 ± 0.77 mm (bottled), 9.8 ± 0.18 mm (RO), and 17.6 ± 1.19 mm (tap), with the first three classified as resistant and tap water as sensitive. The tap water results were significantly different (p<0.05) from those of the other antibiotics. Conclusion The use of non-standard solvents in MHA preparation, particularly tap water, may lead to inconsistent antibiotic susceptibility results. Standardized use of distilled water is recommended to ensure test accuracy and reliability.
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Mwanzo, Wavindu, B. Mouafo Tamnou Edith, Soly Kamwira Ildephonse, et al. "Susceptibility of some Enterobacteriaceae isolated from 4 different aquatic environments in DR Congo (Central Africa), to Amoxicillin/Clavulanic acid and some 3rd generation Cephalosporins." GSC Biological and Pharmaceutical Sciences 26, no. 1 (2024): 178–90. https://doi.org/10.5281/zenodo.10969358.
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Little is known about the variation of the antibiotic susceptibility of different bacterial strains of the same cells species, isolated from different aquatic environments. The present study aims to evaluate the susceptibility towards some 3<sup>rd</sup> generation cephalosporins (Ceftriaxon, Ceftazidim and Cefotaxim) and Amoxicillin/Clavulanic acid, of Enterobacteriaceae strains isolated from groundwater, stream, hospital wastewater and slaughterhouse wastewater. Enterobacteria species were isolated on Mac Conkey agar, then identified using enzymatic and MALDI-TOF MS system. The antimicrobial susceptibility was carried out using the disk diffusion method. The antibiotic minimum inhibitory concentrations (MICs) were carried using the VITEK<sup>®</sup>2 system. Bacterial species mostly identified were <em>Klebsiella pneumoniae, Escherichia coli, Salmonella typhi</em> and <em>Ewingelia americana</em>. The antibiotic inhibition diameters and the MICs varied depending on the antibiotics, bacterial species and type of aquatic environment hosting the microorganism. Relatively lower MICs were recorded with Cefotaxim against different bacteria in slaughterhouse wastewater, in river water and in well water. Antibiotic resistance was noted with all strains from hospital wastewater. Significant differences (P˂0.05) amongst antibiotic inhibition diameter was noted for <em>K. pneumoniae</em> and <em>S. typhi</em> in most cases. The relative variations in the action mechanisms amongst antibiotics and the intrinsic defense potential of each bacterial strain, as well as the potential influence of the physicochemical properties of each water medium, could partly be at the origin of the relative differences observed at the phenotypic level. It seems necessary to explore the diversity, similarities and differences amongst antibiotic resistance genes in these different types of aquatic biotopes.
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Justen, Alexander M., Heather L. Hodges, Lili M. Kim, et al. "Polysaccharide length affects mycobacterial cell shape and antibiotic susceptibility." Science Advances 6, no. 38 (2020): eaba4015. http://dx.doi.org/10.1126/sciadv.aba4015.
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Bacteria control the length of their polysaccharides, which can control cell viability, physiology, virulence, and immune evasion. Polysaccharide chain length affects immunomodulation, but its impact on bacterial physiology and antibiotic susceptibility was unclear. We probed the consequences of truncating the mycobacterial galactan, an essential linear polysaccharide of about 30 residues. Galactan covalently bridges cell envelope layers, with the outermost cell wall linkage point occurring at residue 12. Reducing galactan chain length by approximately half compromises fitness, alters cell morphology, and increases the potency of hydrophobic antibiotics. Systematic variation of the galactan chain length revealed that it determines periplasm size. Thus, glycan chain length can directly affect cellular physiology and antibiotic activity, and mycobacterial glycans, not proteins, regulate periplasm size.
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Menció, Anna, and Josep Mas-Pla. "Assessing the Influence of Environmental Factors on Groundwater Antibiotic Occurrence by Means of Variation Partitioning." Water 11, no. 7 (2019): 1495. http://dx.doi.org/10.3390/w11071495.
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The spatial distribution of antibiotics in alluvial aquifers presents a large variability caused by the joint action of several factors including hydrology, land use, and groundwater properties. In this study, the influences of these factors on the spatial variability of antibiotics is evaluated based on an extensive database of 47 wells located in the Baix Fluvià alluvial aquifer (NE Catalonia). Statistical methods such as redundancy and variation partitioning (VP) analyses, which are not commonly used in hydrogeological studies, are herein tested and used to estimate the effects of environmental factors on the observed antibiotic occurrence. Using VP, the total explained variation of the antibiotic distribution only reaches 18% of the total variability, meaning that the whole set of explanatory parameters is insufficient or inadequate to describe the occurrence of antibiotics and their concentration. The results point out that groundwater properties are the most representative parameters, while those related to antibiotic sources and aquifer susceptibility have lower influences. Omitting solute transport parameters that actually govern antibiotic fate (i.e., sorption coefficients and degradation rates) from the statistical analysis limited the success of the VP results. VP thus highlights the importance of researching antibiotic transport in groundwater by determining the reactive properties of these pollutants above other hydrogeochemical variables. We conclude that the present capacity to predict antibiotic existence at a specific location—for instance, a supply well—based on field data is still poor and unrepresentative, being an impediment for groundwater pollution management.
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Okoye, Elochukwu Chidubem Sunday, Nnachetam Anthony Egudu, Nwamaka Anthonia Dibua, and Lydia Chidimma Okoye. "Seasonal Variation and Antibiotic Susceptibility Patterns of Bacteriological Parameters in Groundwater Sources in Oyi LGA, Anambra State, Nigeria." Journal of Advances in Microbiology 24, no. 5 (2024): 40–55. http://dx.doi.org/10.9734/jamb/2024/v24i5825.
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Potable water is essential for health and survival of all life forms. Contamination of groundwater sources by microbes, organic and inorganic matter has continued to negatively affect the well-being of most people in developing countries such as Nigeria. Thus, this study aimed to determine the seasonal variation and antibiotic susceptibility patterns of bacteriological parameters in groundwater sources in Oyi LGA, Anambra State, Nigeria. Hand-dug well and borehole water sites were randomly selected in five communities of Oyi LGA, and water samples were aseptically collected and analyzed using standard microbiological procedures. The total heterotrophic counts of bacteria isolated from groundwater samples during both seasons were between 1.3×102 and 2.87×104 CFU/mL, total coliform counts ranged from 2 to 165 MPN/100mL and faecal coliform ranged from 0 to 32 MPN/100mL. Probable bacterial isolates in groundwater samples were Escherichia coli, Klebsiella aerogenes, Shigella flexneri, Enterococcus faecalis and Enterobacter sp. Seasonal variations showed there were more bacterial loads in sampled water during wet season than dry season. Antibiotic susceptibility test revealed that all the bacterial isolates were sensitive to Levofloxacin and Ofloxacin, and are recommended for treatment of diseases caused by some of these pathogens. Shigella flexneri exhibited highest susceptibility (60%) to the antibiotics, while Enterobacter faecalis showed highest resistance (70%). Escherichia coli exhibited 50% susceptibility and 50% resistance. The sampled water sources did not meet the WHO and NSDWQ guidelines for drinking water, and therefore not fit for human consumption without adequate treatment.
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Tripathi, Kshama, and A. K. Sharma. "Seasonal variation in bacterial contamination of water sources with antibiotic resistant faecal coliforms in relation to pollution." Journal of Applied and Natural Science 3, no. 2 (2011): 298–302. http://dx.doi.org/10.31018/jans.v3i2.202.
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Water sample were collected from piped supplies, surface water and ground water sources in different locations of Lucknow city during summer, monsoon and winter season. Bacteriological quality of samples was determined by enumerating coliform isolated were subject to antibiotic susceptibility test with disc diffusion method. Maximum coliform and faecal coliform contamination were recorded during summer (67% and 75%) and monsoon (67% and 58.3%) while minimum during winter (50% and 50%). All the test isolates exhibited resistance (for nine antibiotics) was shown by river isolates. Antibiotic resistance index (ARI) ranged from 0.050 to 0.150 exhibiting the broad spectrum resistance for 3 to 9 out of 10 antibiotics tested. Occurrence of faecal pollution indicator organisms and multiple antibiotics resistance bacterial population in drinking water is alarming and a sign of potential health with therapeutic problems.
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KALMEGH, ANUP N., ANBAZHAGAN S, RAJNEESH RANA, ZUNJAR B. DUBAL, and PALLAB CHAUDHURI. "Antimicrobial susceptibility profiles of Mycoplasma mycoides subsp. capri field isolates from goats in India." Indian Journal of Animal Sciences 90, no. 8 (2021): 1123–25. http://dx.doi.org/10.56093/ijans.v90i8.109290.
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Erythromycin and Tylosin (Macrolides) followed by Tetracycline and Doxycycline (Tetracyclines) are found to be the best drugs of choice, under in-vitro antibiotic sensitivity test conducted with Disc diffusion method for the 10 Indian Mmc isolates recovered from goats. These relevant antibiotics may be recommended for use under field conditions. Although we have to keep in mind the gene exchange in Mollicutes along with other mechanisms, which may lead to the variation in their sensitivity to antibiotics in coming time.
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Thanasai, Jongkonnee, Sa-Ngob Laklaeng, Supphachoke Khemla, et al. "Global Prevalence of Antibiotic-Resistant Burkholderia pseudomallei in Melioidosis Patients: A Systematic Review and Meta-Analysis." Antibiotics 14, no. 7 (2025): 647. https://doi.org/10.3390/antibiotics14070647.
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Background: Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to multiple antibiotics, posing substantial challenges for treatment. Reports of acquired resistance are increasing, underscoring the need for global surveillance. Objective: This systematic review and meta-analysis aimed to determine the global prevalence of antibiotic-resistant B. pseudomallei isolated from human clinical cases, with a focus on regional differences and variations in antimicrobial susceptibility testing methods. Methods: We systematically searched PubMed, Scopus, and Embase for studies reporting resistance in clinical B. pseudomallei isolates, following PRISMA guidelines. Pooled resistance rates to 11 antibiotics were calculated using a random-effect model. Subgroup analyses were performed based on geographical region and testing methodology (MIC vs. disk diffusion). Results: Twelve studies comprising 10,391 isolates were included. Resistance rates varied across antibiotics, with the highest pooled resistance observed for tigecycline (46.3%) and ciprofloxacin (38.3%). Ceftazidime (CAZ) and trimethoprim–sulfamethoxazole (SXT), commonly used first-line agents, showed resistance rates of 5.3% and 4.2%, respectively. Subgroup analyses of CAZ and SXT revealed significantly higher resistance in studies from Asia compared to Australia and America (p value < 0.0001). Disk diffusion methods tended to overestimate resistance compared to MIC-based approaches, which revealed non-significant differences for CAZ (p value = 0.5343) but significant differences for SXT (p value < 0.0001). Conclusions: Antibiotic resistance in B. pseudomallei exhibits regional variation and is influenced by the susceptibility testing method used. Surveillance programs and standardized antimicrobial susceptibility testing protocols are essential to guide effective treatment strategies and ensure accurate resistance reporting.
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Hassan, Fatima J., Intesar N. Khelkal, Mohammed F. Al Marjani, and Amira A. Moawad. "The Effect of pH Variation on Antibiotic Susceptibility of MDR <i>Klebsiella pneumoniae</i> Isolates." Al-Mustansiriyah Journal of Science 35, no. 2 (2024): 37–42. http://dx.doi.org/10.23851/mjs.v35i2.1394.
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Background: Klebsiella pneumoniae is a significant opportunistic pathogen responsible for various nosocomial infections in humans. The emergence of multi-drug resistant strains poses a significant challenge in clinical settings, necessitating a deeper understanding of factors influencing antimicrobial resistance. Objective: This research aimed to investigate the impact of pH variation on the resistance patterns of multi-resistant K. pneumoniae isolated from Iraqi patients with urinary tract infections and wound infections against different antibiotics. Methods: Forty K. pneumoniae isolates were obtained from urine samples and wound swabs, and their identification was confirmed using the VITEK ® 2 compact system and molecular identification of the rpoB housekeeping gene. Antibiotic susceptibility testing was performed using the Kirby Bauer’s disk diffusion method under varying pH conditions (pH 5, 7, 9, and 11) at 37°C for 18 to 24 hours. Results: The study findings indicated that K. pneumoniae isolates exhibited differential susceptibility to antibiotics based on pH conditions. Cefotaxime demonstrated increased efficacy under alkaline pH, while tetracycline showed optimal efficacy under acidic conditions. However, ciprofloxacin displayed resistant phenotypes at acidic pH 5 and either resistant or intermediate phenotypes at alkaline pH 9. Conclusions: The results suggest a potential influence of pH on the antibiotic susceptibility profiles of K. pneumoniae isolates. Understanding the role of pH in antimicrobial resistance can inform strategies for better managing infections caused by multi-resistant pathogens. Further research is warranted to elucidate the underlying mechanisms and implications for clinical practice.
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Grujović, Mirjana, Tanja Žugić-Petrović, and Katarina Marković. "Safety assessment and antimicrobial potential of Enterococcus spp. isolated from raw goat milk and cheese." Kragujevac Journal of Science 46, no. 2 (2024): 49–62. https://doi.org/10.5937/kgjsci2402049g.
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This study aimed to assess the safety and antimicrobial properties of Enterococcus species isolated from raw goat milk and cheese. The isolates were evaluated for hemolytic activity on blood agar plates and antibiotic susceptibility by determining the minimum inhibitory concentrations (MICs) of five antibiotics: ampicillin, tetracycline, gentamicin, streptomycin, and vancomycin. Furthermore, the antagonistic activity of the Enterococcus strains against indicator bacteria was assessed using the agar-well diffusion method. Hemolytic activity results demonstrated a-hemolysis in all isolates. Among the 71 Enterococcus isolates examined, 32.39% exhibited resistance to at least one antibiotic, with resistance profiles varying between species. Enterococcus faecalis isolates predominantly showed resistance to vancomycin, ampicillin, tetracycline, and gentamicin, while Enterococcus faecium and Enterococcus hirae displayed resistance to vancomycin with different susceptibility patterns to the other antibiotics. The antagonistic assays revealed a broad spectrum of inhibitory effects, with variation in inhibition zone diameters. These findings provide valuable insights into the safety and antimicrobial potential of Enterococcus spp. from raw goat milk and cheese and give an insight into their potential applications in the food industry.
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Fenelon, Hannah T., Stephen E. Hawes, Hema Kapoor, Ann E. Salm, Jeff Radcliff, and Peter M. Rabinowitz. "Regional Variation in Urinary Escherichia coli Resistance Among Outpatients in Washington State, 2013–2019." Microorganisms 12, no. 11 (2024): 2313. http://dx.doi.org/10.3390/microorganisms12112313.
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Escherichia coli (E. coli) is a predominant pathogen of urinary tract infections (UTIs) in the United States. We analyzed resistance patterns by geographic location in Washington State to assess the need for regional antibiograms. The study included urinary E. coli antibiotic susceptibility tests performed by Quest Diagnostics on Washington outpatient isolates from 2013 to 2019. We conducted logistic regressions with robust standard errors for five antibiotics (ceftriaxone, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole), with isolates classified as “susceptible” or “resistant” for each antibiotic tested. Analyses were adjusted for sex, year of isolate collection, and age group (0–18, 19–50, >50). The state’s nine Public Health Emergency Preparedness Regions (PHEPRs) were used as the geographic level for the analysis. The analysis included 40,217 isolates (93% from females, mean age 47 years). Compared to the Central PHEPR (containing Seattle), most other regions had significantly lower adjusted prevalence ratios (aPORs) of antimicrobial resistance (AMR), with aPORs as low as 0.20 (95% CI: 0.06–0.63) for ceftriaxone in the North Central region. Additionally, no regions had significantly higher aPOR of resistance for any antibiotic. Differences in resistance between the Central and other regions varied by antibiotic with the largest difference for ceftriaxone and smallest for ampicillin. The finding of regional variation of E. coli AMR calls for more specific community antibiograms to enable a precise approach to antibiotic prescribing and stewardship.
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Motaweq, Zahraa Y., and Habeeb S. Naher. "Antimicrobial susceptibility of Streptococcus pneumoniae isolates causing LRTI in Najaf, Iraq." Environmental & Socio-economic Studies 5, no. 2 (2017): 10–18. http://dx.doi.org/10.1515/environ-2017-0007.
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Abstract During the period from February 2013 to April 2014, 74 (12.3%) isolates of Streptococcus pneumoniae were isolated from 600 patients (359 males and 241 females) with clinical symptoms of Lower respiratory tract infections (LRTI) (pneumonia and COPD) obtained from Najaf/Iraq Hospitals. Patients in the age groups 51-60 years had a high percentage of S. pneumoniae isolates (19.7%) compared with other age groups with a significant variation (P<0.05) between them. Males (54%) showed a higher percentage of S. pneumoniae isolates than females (45.9%) with no significant variation (P>0.05). Smokers have been shown to have increased risk to LRTI than non-smokers (P>0.05), and there was no significant variation between Urban and Rural (56.8:43.2%) patients. S. pneumoniae showed different susceptibilities towards antibiotics used in this study. The highest rate of resistance was against erythromycin (100%), azithromycin (83.8%), clindamycin (83.8%) and trimethoprim/sulfamethaxzol (81.1%) and moderate resistance to ceftriaxone (67.6%), cefotaxime (64.9%), chloramphenicol (64.9%), tetracycline (59.5%) and benzylpenicillin (45.9%) whereas there was a relatively lower resistance towards others. The results of this study showed that S. pneumoniae isolates were found to be remarkable sensitive to Vancomycin (100%) and Imipenem (100%). In this study, sixteen antibiotics were tested for (MIC) against 37 S. pneumoniae isolates by using Vitek-2 antibiotic susceptibility testing (AST) cards (41497) AST-GP74. 100% and 83.8% of S. pneumoniae isolates were resistant to erythromycin and SXT with MIC ≥1 mg/ml and 4/76 mg/ml of these antibiotic respectively, and moderately resistant to cefotaxime 64.9%, ceftriaxone 64.9% and chloramphenicol 64.9% with MIC 4 mg/ml for CTX and CRO each one, and MIC 8 mg/ml for C only. All isolates showed 100% sensitivity for each of Vancomycin and Erythromycin with MIC mg/ml and ≤1 mg/ml and ≤2 mg/ml, respectively. S. pneumoniae isolates showed a high rate of sensitivity to Ertapenem 97.3% with MIC ≤1 mg/ml, Telithromycin 89.2% with MIC ≤1, Meropenem 86.5% with MIC ≤0.25 mg/ml.
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Hicks, Nathan D., Samantha R. Giffen, Peter H. Culviner, et al. "Mutations in dnaA and a cryptic interaction site increase drug resistance in Mycobacterium tuberculosis." PLOS Pathogens 16, no. 11 (2020): e1009063. http://dx.doi.org/10.1371/journal.ppat.1009063.
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Genomic dissection of antibiotic resistance in bacterial pathogens has largely focused on genetic changes conferring growth above a single critical concentration of drug. However, reduced susceptibility to antibiotics—even below this breakpoint—is associated with poor treatment outcomes in the clinic, including in tuberculosis. Clinical strains of Mycobacterium tuberculosis exhibit extensive quantitative variation in antibiotic susceptibility but the genetic basis behind this spectrum of drug susceptibility remains ill-defined. Through a genome wide association study, we show that non-synonymous mutations in dnaA, which encodes an essential and highly conserved regulator of DNA replication, are associated with drug resistance in clinical M. tuberculosis strains. We demonstrate that these dnaA mutations specifically enhance M. tuberculosis survival during isoniazid treatment via reduced expression of katG, the activator of isoniazid. To identify DnaA interactors relevant to this phenotype, we perform the first genome-wide biochemical mapping of DnaA binding sites in mycobacteria which reveals a DnaA interaction site that is the target of recurrent mutation in clinical strains. Reconstructing clinically prevalent mutations in this DnaA interaction site reproduces the phenotypes of dnaA mutants, suggesting that clinical strains of M. tuberculosis have evolved mutations in a previously uncharacterized DnaA pathway that quantitatively increases resistance to the key first-line antibiotic isoniazid. Discovering genetic mechanisms that reduce drug susceptibility and support the evolution of high-level drug resistance will guide development of biomarkers capable of prospectively identifying patients at risk of treatment failure in the clinic.
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Mo, Licai, Jiajia Wang, Jiao Qian, and Minfei Peng. "Antibiotic Sensitivity of Proteus mirabilis Urinary Tract Infection in Patients with Urinary Calculi." International Journal of Clinical Practice 2022 (December 21, 2022): 1–6. http://dx.doi.org/10.1155/2022/7273627.
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Background. The study’s objective was to determine Proteus mirabilis susceptibility in individuals with urinary tract infections and stones to antibiotics and prescribe optimal antimicrobial treatment. Methods. Nonrepetitive Proteus mirabilis strains were isolated from urine specimens obtained from 317 patients diagnosed with urinary stones from January, 2018, to December, 2021. A VITEK mass spectrometer was used for species identification, and a VITEK-compact 2 automatic microbial system was used for the antimicrobial susceptibility test (AST). Susceptibility to imipenem and cefoperazone/sodium sulbactam was tested by the disc diffusion method (K-B method). The antibiotic sensitivity of the strains was analyzed by sex and season. Results. A total of 317 patients were reviewed: 202 females (63.7%) and 115 males (36.3%). Proteus mirabilis infections were observed during spring (21.8%, n = 69), summer (26.2%, n = 83), autumn (33.8%, n = 107), and winter (18.2%, n = 57). Proteus mirabilis infections in females were diagnosed most often during the fall (24.3%, n = 77) and during the summer in males (11.0%, n = 35) ( p = 0.010). Female patients responded best to levofloxacin ( p = 0.014), and male patients responded best to sulfamethoxazole ( p = 0.023). Seasonal variation in antibiotic sensitivity was confirmed, with significantly higher rates in the winter for cefuroxime ( p = 0.002) and sulfamethoxazole ( p = 0.002). Significant seasonal increases were also found in levofloxacin sensitivity during the summer ( p = 0.005). Conclusions. Highly effective antibiotics such as cefoxitin and ceftazidime should be used empirically by considering antibiotic sensitivity changes by sex, season, and year. Regional studies should be conducted frequently.
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Khattak, Zainab, Roohul Aala, Nimra Sani, et al. "Prevalence and antimicrobial susceptibility of Salmonella enterica Typhi in febrile patients: a cross-sectional study." Journal of Infection in Developing Countries 19, no. 06 (2025): 904–12. https://doi.org/10.3855/jidc.20373.
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Introduction: Typhoid fever, caused by Salmonella Typhi, is a serious health problem, especially in developing countries like Pakistan where antibiotics are usually prescribed without susceptibility testing or epidemiological surveillance. Consequently, antibiotic-resistant typhoid bacteria appear, but are not reported to the authorities. There is limited research on the prevalence and antibiotic susceptibility patterns of S. Typhi among febrile patients in Swabi, Pakistan. This study aimed to address this gap at the Bacha Khan Medical Complex in Swabi. Methodology: Laboratory records of hospitalized patients who received a blood culture from September 2022 to August 2023 were reviewed in this retrospective, cross-sectional study. Every isolate of S. Typhi underwent antibiotic susceptibility test using modified Kirby-Bauer disk diffusion and agar-dilution methods to measure the isolates' minimum inhibitory concentration (MIC) for ciprofloxacin and azithromycin. The data were analyzed using SPSS version 24.0. Results: 4.85% of febrile patients were positive for S. Typhi, with a higher prevalence in the 0–14 years age group. Male gender and seasonal variation were significant factors. The isolates were resistant to ampicillin, amoxicillin, cefotaxime, and ciprofloxacin; and sensitive to azithromycin, and carbapenems. The MICs for ciprofloxacin were between 0.06 to 16 µg/mL. Among the isolates, 1.094% were sensitive and 98.90% were resistant to ciprofloxacin; and 100% isolates were susceptible to azithromycin. Conclusions: Azithromycin and carbapenem were a suitable empirical therapy choice. However, the isolates were highly resistant to conventional first-line antibiotics (ampicillin, amoxicillin), second generation fluoroquinolones (ciprofloxacin), and third-generation cephalosporins (ceftriaxone, cefotaxime), that are considered vital in typhoid treatment.
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Dr, Duhita Jadhav. "Characterization and Antibiotic Susceptibility Testing Of Acinetobacter Species in a Tertiary Care Hospital with Special Reference to NDM and OXA Genes." International Journal of Medical and Pharmaceutical Research 4, no. 2 (2023): 264–68. https://doi.org/10.5281/zenodo.7823590.
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<strong>Background-</strong><em>Acinetobacter </em>has emerged as a nosocomial pathogen. It was sensitive to most antibiotics, but today it exhibits resistance to most first line antibiotics. Carbapenems are the drug of choice for treating this infection but now resistance to carbapenems is being reported worldwide. Antibiotic susceptibility pattern of <em>Acinetobacter</em> may vary geographically and between various units of the same hospital at various point of time. The variation in antibiogram necessitates a periodic surveillance. Hence this study was conducted to understand the difference in phenotypic and genotypic methods by detection of OXA and NDM genes for accurate identification of antibiotic resistance, thus enabling successful implementation of antibiotic policy. <strong>METHODS- </strong>70 isolates of <em>Acinetobacter</em> were collected and speciated. Antibiotic susceptibility pattern of all the isolates was determined and the carbapenem resistant isolates were subjected to real-time PCR for identification of NDM and OXA genes. <strong>RESULTS- </strong><em>A baumannii</em> was the most common (74.3%) species, followed by <em>A. lwoffii</em> (25.7%). <em>A. lwoffii</em> was 100% sensitive to carbapenems. 50 strains of <em>A. baumannii</em> were carbapenems resistant and remaining were susceptible. In Carbapenem resistant <em>A baumannii</em> OXA 23 and OXA 51 are the most common gene detected by realtime PCR, followed by OXA 48 and OXA 58, while NDM was detected in 100% strains. <strong>DISCUSSION AND CONCLUSION- </strong>Knowledge of NDM and OXA producing <em>Acinetobacter</em> is imperative in formulating Institutional antibiotic stewardship program and infection control practices to control the spread of carbapenem resistant strains of <em>Acinetobacterbaumanii</em>. This information is extremely valuable for pharmaceutical companies towards development of newer antibiotics.
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Ahmed, Sabah Mohan, and KIRAY Esin. "DETECTION AND GENETIC VARIATION OF SPA AND TST-1 GENE IN CLINICAL Staphylococcus aureus SAMPLES IN THI-QAR." EJONS International Journal on Mathematic, Engineering and Natural Sciences 7, no. 3 (2023): 393–406. https://doi.org/10.5281/zenodo.10479022.
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Urinary tract infection (UTI) is one of the most common infectious diseases in humans. Staphylococcus aureus, a gram-positive bacterium, is one of the most common causes of UTI. In this study, it was aimed to investigate the presence and genetic variation of Staphylococcal protein A (spa) and toxic shock syndrome toxin-1 (Tsst-1) gene regions by determining the distribution of S. aureus in urine samples taken from UTI patients in Thi-qar province. Various biochemical methods and API-20 and Vitek2 compact systems were used for the identification of S. aureus. Fourteen different antibiotics, which are frequently used in the clinic, were used to determine the antibiotic susceptibility of the strains. PCR technique was used to determine the presence of spa and tsst-1 genes of S. aureus strains isolated from UTI patients. Genetic variation of strains was determined by DNA sequencing analysis method. In the study, S. aureus was found to be positive in 133 (66.5%) of the urine samples taken from 200 patients with UTI. The highest resistance rates in antibiotic susceptibility of the strains were determined as Ampicillin (100%), Cefoxitin (97.7%), Tetracycline (76.6%), Clindamycin (71.4%) and Trimethoprim-Sulphamethoxazole (54.1%), while Erythromycin (43.6%) and Doxycycline (4%). 42.8) was determined. On the other hand, the strains tested showed a high degree of susceptibility to Vancomycin and Novobiocin. All S. aureus isolates (n=55) were amplified with a 100% positive reaction against the spa gene, while the presence of the tsst-1 gene was determined at 20%. In DNA sequencing analysis, the percentage of genetic variation in the spa gene in native S. aureus isolates was found to be between 0.84-1.05%, while the genetic variation in the tsst-1 gene was found to be 0.23%. As a result of the study, it was seen that there was a significant increase in the prevalence of S. aureus in Iraq, and the genetic variation in the spa and tsst-1 gene was low
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McGregor, Jessina C., Yennie Quach, David T. Bearden, David H. Smith, Susan E. Sharp, and Judith A. Guzman-Cottrill. "Variation in Antibiotic Susceptibility of Uropathogens by Age Among Ambulatory Pediatric Patients." Journal of Pediatric Nursing 29, no. 2 (2014): 152–57. http://dx.doi.org/10.1016/j.pedn.2013.09.001.
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Al-Naqshbandi, Ahmed A., Hedy A. Hassan, Mahmoud A. Chawsheen, and Haval H. Abdul Qader. "Categorization of Bacterial Pathogens Present in Infected Wounds and their Antibiotic Resistance Profile Recovered from Patients Attending Rizgary Hospital-Erbil." ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY 9, no. 2 (2021): 64–70. http://dx.doi.org/10.14500/aro.10864.
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Wound infection with antibiotic-resistant bacteria can extend a patients’ debility and increase the expense of treatment in the long term; therefore, careful management of patients with wound infections is necessary to avoid complications. The usage of antimicrobial agent is a major factor in resistance development. This study aims to understand the causes of wound infections, as well as the criteria for diagnosing them for more sensible antibiotic prescribing. Samples from 269 wound patients were collected, and cultured for bacterial growth. Gram stain technique, bacterial identification via VITEK 2 compact system were investigated in this study. Gram negative bacteria accounted for 59.15% of the total isolates, while pathogenic gram positive bacteria accounted for 40.85% of total isolates. Escherichia coli and Pseudomonas aeruginosa are the dominant pathogenic gram negative bacteria in wounds, while Staphylococcus aureus, and Staphylococcus epidermidis are the dominant pathogenic gram positive bacteria. Pseudomonas aeruginosa showed 100% resistance to the majority of antibiotic tested, including Ampicillin, Amoxicillin/Clavulanic Acid, Aztreona, Ceftriaxone, and others. Staphylococcus aureus and Staphylococcus epidermidis are 100% resistant to Ampicillin, Ceftriaxone, and Cefotaxime. For more efficient antibiotic prescriptions, the causative microorganisms, and their current susceptibility patterns need to be mandated for testing before prescribing any antibiotics to patients. Prescriptions are frequently based solely on general information about the antibiotic's function, rather than on individual response variation to the pathogen and the antibiotic. Particularly when the common pathogens in this study show multidrug resistance in wounds.
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Siddique, Arooba, Saher Mahmood, Sadia Tahir, Izna Tariq, Chaudhry Ahmed Shabbir, and Yasir Arfat. "Characterization and Prevalence of Antibiotic Resistance Staphylococcus aureus in Street Food: A Public Health Concern." TSF Journal of Biology 2, no. 2 (2024): 5–20. http://dx.doi.org/10.69547/tsfjb.020202.
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Food samples containing Staphylococcus aureus pose a serious health risk. This study aimed to examine the prevalence of S. aureus strains in various food samples sourced from Mailsi and Multan. Many food samples including yogurt, bakery products, and raw and cooked food were examined for S. aureus. The isolated strains were confirmed through Mannitol agar fermentation, catalase, coagulase, and urease tests. Hemolysis on blood agar and biofilm formation were also assessed to determine toxin production. Antibiotic sensitivity testing was conducted using the Kirby Bauer method on MH agar, and multiple antibiotics were tested. Out of all samples, a total of 50 S. aureus strains were obtained, mainly from milk and milk-based products. Yellow colonies on mannitol salt agar confirmed S. aureus presence, with all isolates testing positive for coagulase, catalase, and urease. The presence of hemolysins: beta, gamma, and alpha were revealed by hemolysis assays. Biofilm assay results showed variation among the strains, with some categorized as strong, moderate, or weak biofilm formers. Regarding antibiotic sensitivity, most strains exhibited multidrug resistance, particularly against certain antibiotics. Vancomycin showed varying susceptibility patterns, some strains showed susceptibility and intermediate resistance, whereas only milk samples showed resistance. This study emphasizes the prevalence of MDR S. aureus strains in food samples. The study underscores the significance of antimicrobial stewardship programs and stringent food safety measures in preventing the spread of antibiotic-resistant strains and reducing foodborne illnesses. Further research is needed to explore the mechanisms behind antibiotic resistance and toxin production in S. aureus strains from food samples.
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Curiao, Tânia, Emmanuela Marchi, Carlo Viti, et al. "Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics." Antimicrobial Agents and Chemotherapy 59, no. 6 (2015): 3413–23. http://dx.doi.org/10.1128/aac.00187-15.
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ABSTRACTExposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selectedEscherichia coliandKlebsiella pneumoniaemutants.E. coliandK. pneumoniaemutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of thefabIgene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants ofE. coliandK. pneumoniaewere obtained after selection with biocides and/or antibiotics.E. coliTRIrmutants, including those with mutations in thefabIgene or in the expression ofacrB,acrF, andmarA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIrmutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIrmutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIrmutants had fitness costs, particularlymarA-overexpressing (E. coli) orramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIrmutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits.
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MacGowan, Alasdair P., Rosy Reynolds, Alan R. Noel, and Karen E. Bowker. "Bacterial Strain-to-Strain Variation in Pharmacodynamic Index Magnitude, a Hitherto Unconsidered Factor in Establishing Antibiotic Clinical Breakpoints." Antimicrobial Agents and Chemotherapy 53, no. 12 (2009): 5181–84. http://dx.doi.org/10.1128/aac.00118-09.
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ABSTRACT Antibiotic pharmacodynamic modeling allows variations in pathogen susceptibility and human pharmacokinetics to be accounted for when considering antibiotic doses, potential bacterial pathogen targets for therapy, and clinical susceptibility breakpoints. Variation in the pharmacodynamic index (area-under-the-concentration curve to 24 h [AUC24]/MIC; maximum serum concentration of drug in the serum/MIC; time the serum concentration remains higher than the MIC [T > MIC]) is not usually considered. In an in vitro pharmacokinetic model of infection using a dose-ranging design, we established the relationship between AUC24/MIC and the antibacterial effect for moxifloxacin against 10 strains of Staphylococcus aureus. The distributions of AUC24/MIC targets for 24-h bacteriostatic effect and 1-log, 2-log, and 3-log drops in bacterial counts were used to calculate potential clinical breakpoint values, and these were compared with those obtained by the more conventional approach of taking a single AUC24/MIC target. Consideration of the AUC24/MIC as a distribution rather than a single value resulted in a lower clinical breakpoint.
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Petrone, Federica, Carmine Gizzi, Alessandro Andriani, et al. "Investigation of Healthcare-Acquired Infections and Antimicrobial Resistance in an Italian Hematology Department before and during the COVID-19 Pandemic." Microorganisms 12, no. 7 (2024): 1296. http://dx.doi.org/10.3390/microorganisms12071296.
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Background: The COVID-19 pandemic has made antibiotic resistance (AMR) and healthcare-acquired infections (HAIs) increasingly serious problems. Point-prevalence Surveys (PPS) and other surveillance techniques are essential for antimicrobial management and prevention. Methods: In a hematology department of an Italian hospital, the prevalence of HAI, microbiology, and AMR were examined in this retrospective study in two different periods, namely 2019 and 2021 (pre-pandemic and during the pandemic, respectively). Comparisons were made between patient demographics, hospitalization duration, surveillance swabs, and HAIs. Findings: There was no discernible variation in the prevalence of HAI between 2019 and 2021. Higher rates of HAI were connected with longer hospital stays. Variations in antimicrobial susceptibility and species distribution were found by microbiological analysis. Discussion: The incidence of HAI stayed constant during the epidemic. Nevertheless, shifts in antibiotic susceptibility and microbiological profiles highlight the necessity of continuous monitoring and care. Conclusions: Despite the difficulties of COVID-19, ongoing surveillance and infection control initiatives are crucial for halting HAIs and battling antimicrobial resistance (AMR) in healthcare environments. To fully understand the pandemic’s long-term impact on the spread of infectious diseases and antibiotic resistance, more research is required.
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Needs, Sarah Helen, Sultan İlayda Dönmez, and Alexander Daniel Edwards. "Direct microfluidic antibiotic resistance testing in urine with smartphone capture: significant variation in sample matrix interference between individual human urine samples." RSC Advances 11, no. 60 (2021): 38258–63. http://dx.doi.org/10.1039/d1ra06867a.
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Alrebish, Saleh A., Nehad J. Ahmed, Hamed Al Hamed, Ajay Kumar, Hasan S. Yusufoglu, and Amer Hayat Khan. "Antibiotic Susceptibility of Bacterial Pathogens Stratified by Age in a Public Hospital in Qassim." Healthcare 10, no. 9 (2022): 1757. http://dx.doi.org/10.3390/healthcare10091757.
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Antibiotics have completely transformed medical practice by enabling the treatment of infections that were formerly fatal. However, misuse of antibiotics encourages the formation and spread of germs that are resistant to therapy, hastening the emergence of bacterial resistance. This was a retrospective study that aimed to gather information about the variation in bacterial susceptibility of various patient age groups in a public hospital in Qassim, Saudi Arabia from January 2020 to December 2021. The study included reviewing bacterial susceptibility results that were collected from the laboratory department of the hospital. Four thousand seven hundred and sixty-two isolates were collected. The age of 46.41% of the patients was more than 63 years and the age of 28.96% of the patients was less than 48 years. The most prevalent bacteria were Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. The resistance of gram-positive and gram-negative bacteria to different antibiotics in the elderly group was generally higher than the resistance rates in younger patients. For example, in patients less than 48 years old, the resistance of Staphylococcus haemolyticus to clindamycin (53.3%), ampicillin (91.4%), ciprofloxacin (68.2%), erythromycin (86.1%), and penicillin (93.18%) was high. In patients aged more than 63 years, Staphylococcus haemolyticus was highly resistant to sulfamethoxazole (54.8%), clindamycin (63.9%), ampicillin (98.1%), ciprofloxacin (79.1%), erythromycin (93.2%), gentamicin (63.6%), and penicillin (98.7%). Before prescribing the antibiotics, it is important to assess the microbes that patients have and to be aware of the bacterial isolates’ patterns of antibiotic susceptibility among patients of various age groups.
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Blanquart, François, Sonja Lehtinen, and Christophe Fraser. "An evolutionary model to predict the frequency of antibiotic resistance under seasonal antibiotic use, and an application to Streptococcus pneumoniae." Proceedings of the Royal Society B: Biological Sciences 284, no. 1855 (2017): 20170679. http://dx.doi.org/10.1098/rspb.2017.0679.
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The frequency of resistance to antibiotics in Streptococcus pneumoniae has been stable over recent decades. For example, penicillin non-susceptibility in Europe has fluctuated between 12% and 16% without any major time trend. In spite of long-term stability, resistance fluctuates over short time scales, presumably in part due to seasonal fluctuations in antibiotic prescriptions. Here, we develop a model that describes the evolution of antibiotic resistance under selection by multiple antibiotics prescribed at seasonally changing rates. This model was inspired by, and fitted to, published data on monthly antibiotics prescriptions and frequency of resistance in two communities in Israel over 5 years. Seasonal fluctuations in antibiotic usage translate into small fluctuations of the frequency of resistance around the average value. We describe these dynamics using a perturbation approach that encapsulates all ecological and evolutionary forces into a generic model, whose parameters quantify a force stabilizing the frequency of resistance around the equilibrium and the sensitivity of the population to antibiotic selection. Fitting the model to the data revealed a strong stabilizing force, typically two to five times stronger than direct selection due to antibiotics. The strong stabilizing force explains that resistance fluctuates in phase with usage, as antibiotic selection alone would result in resistance fluctuating behind usage with a lag of three months when antibiotic use is seasonal. While most antibiotics selected for increased resistance, intriguingly, cephalosporins selected for decreased resistance to penicillins and macrolides, an effect consistent in the two communities. One extra monthly prescription of cephalosporins per 1000 children decreased the frequency of penicillin-resistant strains by 1.7%. This model emerges under minimal assumptions, quantifies the forces acting on resistance and explains up to 43% of the temporal variation in resistance.
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Subedi, Kusum, Sushma Gautam, Rajeshwori Swar, Charu Arjyal, and Basista Prasad Rijal. "Seasonal Variation of Enteric Fever in Kathmandu Valley and Antibiotic Susceptibility Profile of Salmonella Enterica." Tribhuvan University Journal 36, no. 01 (2021): 18–30. http://dx.doi.org/10.3126/tuj.v36i01.43512.
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Enteric fever is of public health concern globally, more in the developing countries, which has been causing many morbidity and mortality in low- and middle-income countries. It is mostly related to poor sanitation and contaminated drinking water. This study aims to study the seasonal variation of enteric fever seen in Kathmandu valley and antimicrobial susceptibility profiles of the isolated bacteria. Therefore, blood culture of suspected patients of enteric fever was conducted from April 2018 to April 2020 using standard microbiological techniques; antimicrobial susceptibility testing was performed following Clinical and Laboratory Standard Institute -2017 guidelines. During the study, 104 isolates of Salmonella enteric were isolated, of which Salmonella enterica serovar Typhi were 77.9%, while Salmonella enterica serovars Paratyphi A and B were 21.1% and 1% respectively. Although enteric fever was prevalent throughout the year, the highest number of cases was during the summer. With the increase in temperature, there was also an increase in the cases. Antimicrobial susceptibility profile recorded high resistance of isolates towards Nalidixic acid (97.1%) and Ciprofloxacin (91.3%) while 96% sensitivity to both Ampicillin and Cefixime. This study revealed the occurrence of enteric fever throughout the year, but a large number of cases (51%) are concentrated in the monsoon. Similarly, the resistance of fluoroquinolones reached an alarming state making them inappropriate for use. Ampicillin and Cefixime can be the drug of choice for empirical therapy of enteric fever.
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Aćimović, Milica, Lato Pezo, Ivana Čabarkapa, et al. "Variation of Salvia officinalis L. Essential Oil and Hydrolate Composition and Their Antimicrobial Activity." Processes 10, no. 8 (2022): 1608. http://dx.doi.org/10.3390/pr10081608.
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This study aimed to investigate the chemical composition of steam distillate essential oil and corresponding hydrolate obtained from S. officinalis grown in Serbia, as well as the influence of weather conditions (temperature and precipitations) on their chemical profiles. Furthermore, their antimicrobial activity was investigated in vitro. The main compounds in essential oil were cis-thujone, followed by camphor, trans-thujone, and 1,8-cineole, while hydrolate was slightly different from the essential oil, with camphor, cis-thujone, and 1,8-cineole as the main compounds. Among the eight respiratory-associated microorganisms, Klebsiella oxytoca was the most sensitive to the tested EOs (minimum inhibitory concentration (MIC)/minimal bactericidal/fungicidal concentration (MBC/MFC) were 14.20 and 28.4 μL mL−1, respectively). MIC and MBC values of other tested bacteria ranged between 28.40 and 227.25 μL mL−1 while for Candida albicans MIC/MFC ranged from 28.40/56.81 to 56.81–113.63 μL mL−1. Antibiotic susceptibility patterns for the analyzed eight respiratory-associated microorganisms showed an intermediate level of resistance to commonly used antibiotics such as ampicillin, levofloxacin, and ciprofloxacin. As a preliminary approach to the antimicrobial profiling of the tested EO, the obtained results revealed that the tested samples possess remarkable antibacterial activities and could be used to develop pharmaceutical formulations as an alternative to conventional antibiotic therapy.
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Esposito, Silvano, Renato Gioia, Giuseppe De Simone, Silvana Noviello, and Sebastiano Leone. "BACTERIAL EPIDEMIOLOGY AND ANTIMICROBIAL RESISTANCE IN THE SURGERY WARDS OF A LARGE TEACHING HOSPITAL IN SOUTHERN ITALY." Mediterranean Journal of Hematology and Infectious Diseases 7 (May 26, 2015): e2015040. http://dx.doi.org/10.4084/mjhid.2015.040.
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Objectives: Surgical infections represent an increasingly important problem for the National Health System. In this study we retrospectively evaluated the bacterial epidemiology and antimicrobial susceptibility of the microorganisms concerned as well as the utilization of antibiotics in the General and Emergency Surgery wards of a large teaching hospital in southern Italy in the period 2011-2013.Methods: Data concerning bacterial isolates and antimicrobial susceptibility were retrieved from the Vitek II database. The pharmacy provided data about the consumption of antibiotics in the above reported wards. Chi-square or Fisher’s exact test were used to analyze categorical variables.Results: In all, 94 Gram-negative were isolated in 2011, 77 in 2012, and 125 in 2013, Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa always being the most frequently isolated microorganisms. In the same years, there were respectively 105, 93, and 165 Gram-positive isolated, Enterococcus faecalis, Staphylococcus epidermidis and Staphylococcus aureus being the most commonly found. No significant variation in the antibiotic susceptibility pattern was observed, either among Gram-negative or among Gram-positive pathogens; carbapenems (especially meropenem) consumption remained stable over time.Conclusions: Our results show no significant increase in antimicrobial resistance over the period in question, and a higher rate of both MRSA isolates and resistance to carbapenems in A. baumannii compared with other European data.
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Widerström, Micael, Marc Stegger, Anders Johansson, et al. "Heterogeneity of Staphylococcus epidermidis in prosthetic joint infections: time to reevaluate microbiological criteria?" European Journal of Clinical Microbiology & Infectious Diseases 41, no. 1 (2021): 87–97. http://dx.doi.org/10.1007/s10096-021-04352-w.
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Abstract Prosthetic joint infection (PJI) is a feared and challenging to diagnose complication after arthroplasty, with Staphylococcus epidermidis as the major pathogen. One important criteria to define PJI is the detection of phenotypically indistinguishable microorganisms with identical antibiotic susceptibility pattern in at least two different samples. However, owing to phenotypical variation within genetic clones and clonal variation within a phenotype, the criteria may be ambiguous. We investigated the extent of diversity among coagulase-negative staphylococci (CoNS) in PJI and characterised S. epidermidis isolates from PJI samples, specifically multiple S. epidermidis isolates identified in individual PJI patients. We performed a retrospective cohort study on 62 consecutive patients with PJI caused by CoNS from two hospitals in Northern Sweden. In 16/62 (26%) PJIs, multiple S. epidermidis isolates were available for whole-genome analyses. Hospital-adapted multidrug-resistant genetic clones of S. epidermidis were identified in samples from 40/62 (65%) of the patients using a combination of pulsed-field gel electrophoresis and multilocus sequence typing. Whole-genome sequencing showed the presence of multiple sequence types (STs) in 7/16 (44%) PJIs where multiple S. epidermidis isolates were available. Within-patient phenotypical variation in the antibiotic susceptibility and/or whole-genome antibiotic resistance gene content was frequent (11/16, 69%) among isolates with the same ST. The results highlight the ambiguity of S. epidermidis phenotypic characterisation as a diagnostic method in PJI and call for larger systematic studies for determining the frequency of CoNS diversity in PJIs, the implications of such diversity for microbiological diagnostics, and the therapeutic outcomes in patients.
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Aldridge, K. E., and C. V. Sanders. "Antibiotic- and method-dependent variation in susceptibility testing results of Bacteroides fragilis group isolates." Journal of Clinical Microbiology 25, no. 12 (1987): 2317–21. http://dx.doi.org/10.1128/jcm.25.12.2317-2321.1987.
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Vázquez, Julio A., Luisa Arreaza, Colin Block, et al. "Interlaboratory Comparison of Agar Dilution and Etest Methods for Determining the MICs of Antibiotics Used in Management of Neisseria meningitidis Infections." Antimicrobial Agents and Chemotherapy 47, no. 11 (2003): 3430–34. http://dx.doi.org/10.1128/aac.47.11.3430-3434.2003.
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ABSTRACT Previous studies have shown that there is considerable variation in the methods and media used to determine the susceptibility of Neisseria meningitidis to antimicrobial agents in different countries. In this study, national and regional reference laboratories used a standardized methodology to determine the MICs of antibiotics used in the management of meningococcal infection. Fourteen laboratories participated in the study, determining the susceptibility to penicillin G, rifampin, cefotaxime, ceftriaxone, ciprofloxacin, and ofloxacin of a collection of 17 meningococci, of which 11 strains were previously defined as having intermediate resistance to penicillin (PenI) by sequencing and restriction fragment length polymorphism analysis of the penA gene. The MIC was determined by agar dilution and Etest with Mueller-Hinton agar (MH), MH supplemented with sheep blood (MH+B), and MH supplemented with heated (chocolated) blood. Several laboratories encountered problems obtaining confluent growth with unsupplemented MH. MH+B was considered to give the most congruent and reproducible results among the study laboratories. The modal MIC for MH+B for each antibiotic and method was calculated to define the MIC consensus, allowing assessment of each individual laboratory's data in relation to the others. The agreement in each antibiotic/method/medium combination was defined as the percentage of laboratories with a result within one dilution of the modal result. For the whole study, an agreement of 90.6% was observed between agar dilution and Etest methods. The agreement in each laboratory/antibiotic/method combination ranged from 98.2% to 69.7%, with six laboratories demonstrating agreement higher than 90% and 11 more than 80%. The ability of the laboratories to detect the PenI isolates ranged from 18.2% to 100%. The apparent difficulty in interpreting susceptibility to rifampin, particularly with the Etest method, is very interesting.
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Jalil Abed Gatie. "INVESTIGATE OF VIRULENCE- GENES OF PASTEURELLA MULTOCIDA TYPES AND ANTIBIOTIC SUSCEPTIBILITY IN BUFFALOES IN MARSHES OF SOUTH OF IRAQ." University of Thi-Qar Journal of agricultural research 9, no. 1 (2020): 24–37. http://dx.doi.org/10.54174/utjagr.v9i1.101.
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This study was conducted to investigate the incidence of Pasteurella multocida in buffaloes in south of Iraq. A total 393 of different ages and sexes, were clinically examined. Nasal swabs and blood samples were taken . Enrich and Selective medias ,biochemical tests and Gram stain were used. also used antibiotic susceptibility. All positive cases confirmed by polymerase chain reaction with specific primer to P. multocida then use specific primers to detect P.multocida A,B. Also use specific primers to detect some virulence gene (pfhA ; nanH ; ompA ; hgbA) .Prevalence of P. multocida types in marshes area which it appear 35 samples 35% to type A and it significant variation at (P≤0.05) than types (B) which found 65 samples 65 % also it significant variation. Capsular typing of 100 isolates in marshes appeared 35 (35%) to type A , 65 (65 %) to type B with significantly variation between types . Distribution of virulence- genes appeared 75 (75%) to ompA , hgbA 59 (59 %) , nanH 46 ( 46 %) and pfhA 33(33%) with significantly variation between genes .No significant variation of prevalence of virulence- genes between infected and non-infected. Also prevalence of Pasteurella multocida virulence- genes which it appear 49(74.2%);26(76.4%)to ompA , 41(62.1), 18(52.9) to hgbA ; 27(40.9), 19(55.9) to nanH and 20(30,3) ,13(38.3) to pfhA for diseased and non diseased respectively .Prevalence of P.multocida virulence- genes appeared 25(71.4); 50(76.9); to ompA , 18(51.4), 41(63.1); to hgbA ; 16(45), 30(47.6) to nanh and 16(45.7) , 17(27.0); to pfhA for type A and type B respectively.
 The antibiotics susceptibility of 52 isolated which from 25 type B , 25 type A and showed that : Cefotaxime , Cefitrixone, Azithromycin and Tilmicosin founded 100% susceptibility ,followed by Chloromphinocol as 96-92%, Tetracycline 40-32% while Ampicilline32-28 %.
 Conclusions of present study are : P. multocida endemic in buffaloes in south of Iraq. Recoded of virulence genes of P. multocida in buffaloes in Iraq. Cefotaxime , Cefitrixone, Azithromycin and Tilmicosin are the best choice to treatment. PCR assay is best technique to diagnosis and detect.
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Wood, Bruce W., and Charles C. Reilly. "Susceptibility of Pecan to Black Pecan Aphids." HortScience 33, no. 5 (1998): 798–801. http://dx.doi.org/10.21273/hortsci.33.5.798.
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The host-parasite interaction between the black pecan aphid (BPA) [Melanocallis caryaefoliae (Davis)] and pecan [Carya illinoensis (Wangenh.) K. Koch] was investigated. Three years of field observations of the ability of BPA populations to induce chlorotic blotches, or visual damage, on 32 pecan cultivars revealed considerable variation in cultivar susceptibility to BPA damage. Among the most commonly grown cultivars, `Sioux', `Cape Fear', `Farley', `Cowley', `Grabohls', and `Barton' exhibited the least damage, whereas `Choctaw', `Oconee', and `Sumner' exhibited the greatest, with `Sioux' and `Choctaw' exhibiting the greatest extremes in susceptibility. Subsequent evaluation indicated that the foliage of pecan genotypes can exhibit an antibiotic-like effect, resulting in the suppression of resident BPA populations. However, the relationship between the degree of this antibiotic effect and the degree of damage exhibited by trees, or field tolerance, was negligible (r = -0.10). For example, while `Choctaw' foliage greatly suppressed BPA population growth, this population was able to inflict relatively severe damage to leaves. An evaluation of feeding preference indicated that BPA alate viviparae (winged females) preferentially feed upon host cultivars on which they have been previously feeding. This feeding preference was eliminated by rinsing leaves with distilled water; hence, a water soluble factor(s) appears to be involved in host preference.
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Vernel-Pauillac, Frédérique, and Fabrice Merien. "A Novel Real-Time Duplex PCR Assay for Detecting penA and ponA Genotypes in Neisseria gonorrhoeae: Comparison with Phenotypes Determined by the E-Test." Clinical Chemistry 52, no. 12 (2006): 2294–96. http://dx.doi.org/10.1373/clinchem.2006.075309.
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Abstract Background: For many years, the pathogenic bacterium Neisseria gonorrhoeae, the etiologic agent of gonorrhea, was generally susceptible to penicillin, until the emergence of resistant strains. Well-characterized genetic variations in the penicillin resistance–determining region correlate with decreased susceptibility to penicillin. At least 5 genes (penA, penB, mtrR, ponA, and penC) are involved in the chromosomally mediated resistance to this antibiotic. To date, no development of multiplex PCR assays targeting a range of gonococcal genes and variations as a means of predicting antibiotic resistance has been reported. Methods: The aim of this study was to develop a duplex assay using DNA from isolated strains. We describe the development and evaluation on the LightCycler platform of a real-time duplex PCR assay (hybridization probe format) for rapid and specific detection of ponA and penA variations, predicting penicillin susceptibilities. Results: The real-time duplex PCR assay successfully detected variations in ponA and penA genes by use of distinct melting temperatures from a total of 120 Neisseria gonorrhoeae isolates. Moreover, the variation profiles obtained with the real-time PCR and the melting analysis showed good correlation with the pattern of penicillin susceptibility generated with classical antibiograms. Nucleotide sequencing data were in complete agreement with multiplex assay results. Conclusions: The presented assay is suitable for the detection of chromosomally mediated resistant strains of Neisseria gonorrhoeae in genotyping studies and could be valuable in the effective antimicrobial strategy to gonococci.
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Vaz-Moreira, Ivone, Olga C. Nunes, and Célia M. Manaia. "Diversity and Antibiotic Resistance Patterns of Sphingomonadaceae Isolates from Drinking Water." Applied and Environmental Microbiology 77, no. 16 (2011): 5697–706. http://dx.doi.org/10.1128/aem.00579-11.
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ABSTRACTSphingomonadaceae(n= 86) were isolated from a drinking water treatment plant (n= 6), tap water (n= 55), cup fillers for dental chairs (n= 21), and a water demineralization filter (n= 4). The bacterial isolates were identified based on analysis of the 16S rRNA gene sequence, and intraspecies variation was assessed on the basis ofatpDgene sequence analysis. The isolates were identified as members of the generaSphingomonas(n= 27),Sphingobium(n= 28),Novosphingobium(n= 12),Sphingopyxis(n= 7), andBlastomonas(n= 12). The patterns of susceptibility to five classes of antibiotics were analyzed and compared for the different sites of isolation and taxonomic groups. Colistin resistance was observed to be intrinsic (92%). The highest antibiotic resistance prevalence values were observed in members of the generaSphingomonasandSphingobiumand for beta-lactams, ciprofloxacin, and cotrimoxazole. In tap water and in water from dental chairs, antibiotic resistance was more prevalent than in the other samples, mainly due to the predominance of isolates of the generaSphingomonasandSphingobium. These two genera presented distinct patterns of association with antibiotic resistance, suggesting different paths of resistance development. Antibiotic resistance patterns were often related to the species rather than to the site or strain, suggesting the importance of vertical resistance transmission in these bacteria. This is the first study demonstrating that members of the familySphingomonadaceaeare potential reservoirs of antibiotic resistance in drinking water.
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Kadri, Sameer S., Yi Ling Lai, Emily Ricotta, et al. "Epidemiology of Inappropriate Empiric Antibiotic Therapy for Bacteremia Based on Discordant In vitro Susceptibilities: Risk factors and Taxon-level Variation in Burden and Outcome in 156 US hospitals, 2000–2014." Open Forum Infectious Diseases 4, suppl_1 (2017): S13—S14. http://dx.doi.org/10.1093/ofid/ofx162.032.
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Abstract Background Discordance between in vitro susceptibility and empiric antibiotic therapy is inextricably linked to antibiotic resistance and decreased survival in bloodstream infections (BSI). However, its prevalence, patient- and hospital-level risk factors, and impact on outcome in a large cohort and across different pathogens remain unclear. Methods We examined in vitro susceptibility interpretations for bacterial BSI and corresponding antibiotic therapy among inpatient encounters across 156 hospitals from 2000 to 2014 in the Cerner Healthfacts database. Discordance was defined as nonsusceptibility to initial therapy administered from 2 days before pathogen isolation to 1 day before final susceptibility reporting. Discordance prevalence was compared across taxa; risk factors and its association with in-hospital mortality were evaluated by logistic regression. Adjusted odds ratios (aOR) were estimated for pathogen-, patient- and facility-level factors. Results Of 33,161 unique encounters with BSIs, 4,219 (13%) at 123 hospitals met criteria for discordant antibiotic therapy, ranging from 3% for pneumococci to 55% for E. faecium. Discordance was higher in recent years (2010–2014 vs. 2005–2009) and was associated with older age, lower baseline SOFA score, urinary (vs. abdominal) source and hospital-onset BSI, as well as ≥500-bed, Midwestern, non-teaching, and rural hospitals. Discordant antibiotic therapy increased the risk of death [aOR = 1.3 [95% CI 1.1–1.4]). Among Gram-negative taxa, discordant therapy increased risk of mortality associated with Enterobacteriaceae (aOR = 1.3 [1.0–1.6]) and non-fermenters (aOR = 1.7 [1.1–2.5]). Among Gram-positive taxa, risk of mortality from discordant therapy was significantly higher for S. aureus (aOR = 1.3 [1.1–1.6]) but unchanged for streptococcal or enterococcal BSIs. Conclusion The prevalence of discordant antibiotic therapy displayed extensive taxon-level variability and was associated with patient and institutional factors. Discordance detrimentally impacted survival in Gram-negative and S. aureus BSIs. Understanding reasons behind observed differences in discordance risk and their impact on outcomes could inform stewardship efforts and guidelines for empiric therapy in sepsis. Disclosures All authors: No reported disclosures.
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Rojas, Laura J., Steven Marshall, Mohamad Yasmin, et al. "234. Reversal of Carbapenem and Amikacin Susceptibilities in Isogenic Klebsiella pneumoniae From a Patient with Persistent Bacteriuria." Open Forum Infectious Diseases 6, Supplement_2 (2019): S134. http://dx.doi.org/10.1093/ofid/ofz360.309.
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Abstract Background Genomic tools permit a detailed analysis of antibiotic resistance determinants in bacteria, or resistome. Here we discuss variations in antibiotic resistance in K. pneumoniae (Kp) not explained by changes in the resistome Methods We compared Kp strains with divergent carbapenem and aminoglycoside susceptibilities. After identification of bacteria, antibiotic susceptibility testing was performed according to CLSI guidelines. Draft genome sequences were generated using Illumina MiSeq (Nextera paired-end library) and assembled using CLC Genomics Workbench (CLC bio, Cambridge, MA). Resistome, plasmid types and MLST were investigated using the CGE platform (http://cge.cbs.dtu.dk), while capsular type and virulence genes were investigated using the Pasteur BIGsDB database (https://bigsdb.pasteur.fr). Results While receiving amoxicillin-clavulanate, a 44-year old man with diabetes mellitus and paraplegia with neurogenic bladder grewKp resistant to carbapenems and amikacin from urine. He was treated with fosfomycin and amikacin, followed by imipenem and plazomicin, prior to lithotripsy. Three months later, while off antibiotics, urine cultures grew Kp susceptible to carbapenems and amikacin (figure). Genetic comparison between resistant (November 20, 2018) and susceptible (January 30, 2019) strains revealed they were isogenic, only differing by 559 SNPs (table). Both were ST14, presented capsular type 16, and shared cehalosporinase (blaSHV-28, blaCTX-M-15, blaTEM-1B, blaOXA-1) and aminoglycoside modifying enzyme (AME) (aph(3’’)-Ib, aph(6)-Id, aac(6’)-Ib-cr) genes. Although both had mutations in the outer membrane porin OmpK36, these differed (stop AA125 and frameshift AA183, respectively) Conclusion Carbapenem resistance in the initial Kp is likely explained by overexpression of cephalosporinases in combination with changes in membrane permeability, while amikacin resistance is likely due to AMEs. Since no significant gene variation was observed in the susceptible Kp, reversal of resistance was likely due to decreased expression of cephalosporinases and AMEs after antibiotics were stopped. Incorporation of antibiotic history and host factors can explain clinically important changes in antibiotic resistance Disclosures All authors: No reported disclosures.
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Nikolaisen, Nanett Kvist, Mette Fertner, Desiree Corvera Kløve Lassen, et al. "Association between Antibiotic Consumption and Resistance in Mink Production." Antibiotics 11, no. 7 (2022): 927. http://dx.doi.org/10.3390/antibiotics11070927.
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Antibiotic consumption is considered to be a main driver of antibiotic resistant bacteria. Mink breeding follows a distinctive seasonal reproduction cycle, and all of the mink produced in the northern hemisphere are bred, born, and pelted around the same time of year. Some of the diseases are age-related, which is reflected in the seasonal variation of antibiotic consumption. The seasonality makes mink a good model for the investigation of the association between antibiotic consumption and resistance. The objectives of this study were (1) to monitor the farm level of antibiotic resistance during one production cycle and (2) to assess the potential associations between antibiotic consumption and resistance. Twenty-four farms were included in this study (Denmark n = 20, Iceland n = 2, and The Netherlands n = 2), following a cohort of animals born in 2018. Staphylococcus delphini and Escherichia coli were isolated from samples of the carcasses and faeces and were collected randomly. The isolates were susceptibility tested and subsequently divided into the sensitive wildtype (WT) and the resistant non-wildtype (NWT) populations. The antibiotic consumption relative to the sampling periods was assessed as having a short-term or a long-term impact, i.e., in two explanatory factors. For both S. delphini and E. coli, a large between-farm variation of NWT profiles was detected. In the final multivariable, generalized linear mixed models, significant associations between NWT isolates and the consumption of specific antibiotics were found: the short-term use of tetracyclines in the growth period was associated with the occurrence of tetracycline NWT E. coli in the growth period (OR: 11.94 [1.78; 89.28]), and the long-term use of macrolide and tetracyclines was associated with the occurrence of erythromycin NWT S. delphini in the weaning period (OR: 18.2 [2.26; 321.36]) and tetracycline NWT S. delphini in the growth period (OR: 8.2 [1.27; 63.31]), respectively. Farms with zero consumption in the study years prior to sampling also had a substantial proportion of NWT isolates, indicating that NWT isolates are persistent and/or widely spread in the environment. Generally, a high occurrence of tetracycline NWTs was observed. NWT isolates with resistance against the most commonly used antibiotics were found on all the farms, stressing the need for routine surveillance and the prudent use of antibiotics. The results offer a preview of the complex relationship between consumption and resistance, demonstrating some significant associations between use and resistance. Moreover, antibiotic-resistant bacteria are present even on farms with no antibiotic consumption over extended periods, and theoretical explanations supported by the data are offered.
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Australian Gonococcal Surveillance Programme and John Tapsall. "Annual report of the Australian Gonococcal Surveillance Programme 1996." Communicable Diseases Intelligence 21 (July 10, 1997): 189–92. https://doi.org/10.33321/cdi.1997.21.39.
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In 1996 the Australian Gonococcal Surveillance Programme (AGSP) examined 2,753 isolates of Neisseria gonorrhoeae. The source of isolates, site of infection and antibiotic susceptibility patterns showed considerable regional variation. Strains examined in Adelaide, Sydney and Melbourne were predominantly from male patients where rectal and pharyngeal isolates were common. Cases in other centres had a much lower male:female ratio and most were genital tract isolates. Resistance to the penicillin and quinolone groups of antibiotics was highest in Sydney and Melbourne. Gonococcal resistance to the penicillins was similar to previous years. Quinoloneresistant Neisseria gonorrhoeae (QRNG) were isolated mostly from overseas travellers. However, some local transmission of QRNG was documented in Sydney. All isolates were sensitive to spectinomycin and ceftriaxone. Comm Dis Intell 1997;21:189-192.
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Thulin, Sara, Per Olcén, Hans Fredlund та Magnus Unemo. "Total Variation in the penA Gene of Neisseria meningitidis: Correlation between Susceptibility to β-Lactam Antibiotics and penA Gene Heterogeneity". Antimicrobial Agents and Chemotherapy 50, № 10 (2006): 3317–24. http://dx.doi.org/10.1128/aac.00353-06.
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ABSTRACT In recent decades, the prevalence of Neisseria meningitidis isolates with reduced susceptibility to penicillins has increased. The intermediate resistance to penicillin (Peni) for most strains is due mainly to mosaic structures in the penA gene, encoding penicillin-binding protein 2. In this study, susceptibility to β-lactam antibiotics was determined for 60 Swedish clinical N. meningitidis isolates and 19 reference strains. The penA gene was sequenced and compared to 237 penA sequences from GenBank in order to explore the total identified variation of penA. The divergent mosaic alleles differed by 3% to 24% compared to those of the designated wild-type penA gene. By studying the final 1,143 to 1,149 bp of penA in a sequence alignment, 130 sequence variants were identified. In a 402-bp alignment of the most variable regions, 84 variants were recognized. Good correlation between elevated MICs and the presence of penA mosaic structures was found especially for penicillin G and ampicillin. The Peni isolates comprised an MIC of >0.094 μg/ml for penicillin G and an MIC of >0.064 μg/ml for ampicillin. Ampicillin was the best antibiotic for precise categorization as Pens or Peni. In comparison with the wild-type penA sequence, two specific Peni sites were altered in all except two mosaic penA sequences, which were published in GenBank and no MICs of the corresponding isolates were described. In conclusion, monitoring the relationship between penA sequences and MICs to penicillins is crucial for developing fast and objective methods for susceptibility determination. By studying the penA gene, genotypical determination of susceptibility in culture-negative cases can also be accomplished.
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Rahmati-Bahram, A., J. T. Magee, and S. K. Jackson. "Growth temperature-dependent variation of cell envelope lipids and antibiotic susceptibility in Stenotrophomonas (Xanthomonas) maltophilia." Journal of Antimicrobial Chemotherapy 36, no. 2 (1995): 317–26. http://dx.doi.org/10.1093/jac/36.2.317.
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Gupta, Gunjan, Vibhor Tak та Purva Mathur. "Detection of AmpC β Lactamases in Gram-negative Bacteria". Journal of Laboratory Physicians 6, № 01 (2014): 001–6. http://dx.doi.org/10.4103/0974-2727.129082.
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ABSTRACT AmpC β-lactamases are clinically important cephalosporinases encoded on the chromosomes of many Enterobacteriaceae and a few other organisms, where they mediate resistance to cephalothin, cefazolin, cefoxitin, most penicillins, and β-lactamase inhibitor/β-lactam combinations. The increase in antibiotic resistance among Gram-negative bacteria is a notable example of how bacteria can procure, maintain and express new genetic information that can confer resistance to one or several antibiotics. Detection of organisms producing these enzymes can be difficult, because their presence does not always produce a resistant phenotype on conventional disc diffusion or automated susceptibility testing methods. These enzymes are often associated with potentially fatal laboratory reports of false susceptibility to β-lactams phenotypically. With the world-wide increase in the occurrence, types and rate of dissemination of these enzymes, their early detection is critical. AmpC β-lactamases show tremendous variation in geographic distribution. Thus, their accurate detection and characterization are important from epidemiological, clinical, laboratory, and infection control point of view. This document describes the methods for detection for AmpC β-lactamases, which can be adopted by routine diagnostic laboratories.
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Stuart, J. M., P. M. Robinson, K. Cartwright, and N. D. Noah. "Antibiotic prescribing during an outbreak of meningococcal disease." Epidemiology and Infection 117, no. 1 (1996): 103–5. http://dx.doi.org/10.1017/s0950268800001187.
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SummaryDuring a prolonged outbreak of meningococcal disease caused by serogroup B serotype 15 sulphonamide-resistant strains in one British health district, there was considerable variation in attack rates by town. General practitioner (GP) antibiotic prescribing rates were compared in high and low incidence towns. The only significant difference found was that erythromycin prescribing was more frequent in the high incidence towns (rate ratio 4·0, 95% CI 3·2–4·8, in March 1987 and 3·0, 95% CI 2·4–3·7, in November 1987). This was probably due to increased GP consultation rates for upper respiratory tract infection (URTI), but higher erythromycin usage may have increased meningococcal acquisition rates or susceptibility to meningococcal disease. Antibiotic prescribing rate should be further investigated in defined areas of high and low incidence of meningococcal disease.
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St. Cyr, Sancta, Laura Quilter, Cau D. Pham, Elizabeth Torrone, and Hillard Weinstock. "434. Concurrent Gonococcal Infections with Differing Susceptibility Results from the Enhanced Gonococcal Isolate Surveillance Project (eGISP)." Open Forum Infectious Diseases 6, Supplement_2 (2019): S216. http://dx.doi.org/10.1093/ofid/ofz360.507.
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Abstract Background Concurrent gonococcal infections could impact treatment success in cases of anatomic site-specific strains with different antimicrobial susceptibilities; however, little is known about same-patient differences in susceptibility as most antibiotic resistance surveillance is based on only male urethral isolates. Methods In August 2017, the enhanced Gonococcal Isolate Surveillance Project (eGISP) began collecting male and female genital and extragenital gonococcal isolates from patients in 12 STD clinics. Minimum Inhibitory Concentrations (MICs) for penicillin, tetracycline, ciprofloxacin, gentamicin, cefixime, ceftriaxone and azithromycin were determined by agar dilution. We identified patients with isolates from multiple anatomic sites of infection collected during the same clinic visit. Isolate sets were categorized as pairs or triplets based on the number of culture positive anatomic sites. We identified same-patient isolate sets with differing MICs (≥2 dilution difference) for each antibiotic, and identified if the difference affected susceptibility categorization. All isolates in a set were tested in the same batch run by the same laboratory. Results From August 2017-February 2019, 280 isolates were collected from 135 patients, representing 136 isolate sets (128 pairs and 8 triplets); one patient contributed 2 isolate sets. Of the 136 isolate sets, the majority (72; 53%) were grouped as genital and pharyngeal isolates (Table 1). Overall, 33 isolate sets (24%) had differing MICs for ≥1 antibiotic and 21 sets (15%) for ≥2 antibiotics. Across all anatomical site combinations, differing MICs were most common for ciprofloxacin (10.3%), penicillin (9.6%) and azithromycin (9.6%). Only 18 isolate sets (13%) demonstrated differing MICs where an isolate was considered susceptible and another was considered resistant or reduced-susceptible. Conclusion Among persons with concurrent gonococcal infections, MICs can vary by ≥2 dilutions between sites and may change susceptibility interpretation. Variation by the anatomic site can result from initial infection with multiple strains or differential development of resistance after infection. Continued surveillance of multi-site infections could help understand resistance development and inform patient management. Disclosures All authors: No reported disclosures.
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Mutlu, Esvet, Allison J. Wroe, Karla Sanchez-Hurtado, Jon S. Brazier, and Ian R. Poxton. "Molecular characterization and antimicrobial susceptibility patterns of Clostridium difficile strains isolated from hospitals in south-east Scotland." Journal of Medical Microbiology 56, no. 7 (2007): 921–29. http://dx.doi.org/10.1099/jmm.0.47176-0.
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Clostridium difficile isolates (n=149) collected in south-east Scotland between August and October 2005 were typed by four different methods and their susceptibility to seven different antibiotics was determined. The aims were to define the types of strain occurring in this region and to determine whether there were any clonal relationships among them with respect to genotype and antibiotic resistance pattern. Ribotyping revealed that 001 was the most common type (n=113, 75.8 %), followed by ribotype 106 (12 isolates, 8.1 %). The majority of the isolates (96.6 %, n=144) were of toxinotype 0, with two toxinotype V isolates and single isolates of toxinotypes I, IV and XIII. PCR and restriction analysis of the fliC gene from 147 isolates gave two restriction patterns: 145 of pattern VII and two of pattern I. Binary toxin genes were detected in only three isolates: two isolates of ribotype 126, toxinotype V, and one isolate of ribotype 023, toxinotype IV. S-types showed more variation, with 64.5 % (n=40) of the common S-type (4939) and 21 % (n=13) of S-type 4741, with six other S-types (one to three isolates each). All ribotype 001 isolates were of the same S-type (4939), with three isolates of other ribotypes being this S-type. No resistance was found to metronidazole or vancomycin, with resistance to tetracycline only found in 4.3 % of the isolates. A high proportion of isolates were resistant to clindamycin (62.9 %), moxifloxacin, ceftriaxone (both 87.1 %) and erythromycin (94.8 %). Resistance to three antibiotics (erythromycin, clindamycin and ceftriaxone) was seen in 66 isolates, with erythromycin, ceftriaxone and moxifloxacin resistance seen in 96 isolates. Resistance to all four of these antibiotics was found in 62 isolates and resistance to five (the above plus tetracycline) in one isolate: a ribotype 001, toxinotype 0 strain. Whilst ribotype 001 was the most commonly encountered type, there was no evidence of clonal relationships when all other typing and antibiotic resistance patterns were taken into account.
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Xiong, Huizhong, Rebecca A. Carter, Ingrid M. Leiner, et al. "Distinct Contributions of Neutrophils and CCR2+Monocytes to Pulmonary Clearance of Different Klebsiella pneumoniae Strains." Infection and Immunity 83, no. 9 (2015): 3418–27. http://dx.doi.org/10.1128/iai.00678-15.
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Klebsiella pneumoniaeis a common respiratory pathogen, with some strains having developed broad resistance to clinically available antibiotics. Humans can become infected with many differentK. pneumoniaestrains that vary in genetic background, antibiotic susceptibility, capsule composition, and mucoid phenotype. Genome comparisons have revealed differences betweenK. pneumoniaestrains, but the impact of genomic variability on immune-mediated clearance of pneumonia remains unclear. Experimental studies of pneumonia in mice have used the rodent-adapted 43816 strain ofK. pneumoniaeand demonstrated that neutrophils are essential for optimal host defense. It remains unclear, however, whether CCR2+monocytes contribute toK. pneumoniaeclearance from the lung. We selectively depleted neutrophils, CCR2+monocytes, or both from immunocompetent mice and determined susceptibility to infection by the 43816 strain and 4 newly isolated clinicalK. pneumoniaestrains. The clinicalK. pneumoniaestrains, including one carbapenem-resistant ST258 strain, are less virulent than 43816. Optimal clearance of each of the 5 strains required either neutrophils or CCR2+monocytes. Selective neutrophil depletion markedly worsened infection withK. pneumoniaestrain 43816 and three clinical isolates but did not increase susceptibility of mice to infection with the carbapenem-resistantK. pneumoniaeST258 strain. Depletion of CCR2+monocytes delayed recovery from infection with each of the 5K. pneumoniaestrains, revealing a contribution of these cells to bacterial clearance from the lung. Our findings demonstrate strain-dependent variation in the contributions of neutrophils and CCR2+monocytes to clearance ofK. pneumoniaepulmonary infection.