Antibiotic Resistance Profiles Research Articles

Prevalence and genetic characteristics ofStaphylococcus aureus isolates from cellphones of medical students from Iran.

Although mobile phones as a rapid communication vehicle can lead to improved quality of healthcare, they can also facilitate the transmission of pathogens to patients. This current research focuses on genetic diversity, and genes involved in resistance and biofilm production of Staphylococcus aureus isolates from mobile phones of medical students. Antibiotic resistance profiling and polymerase chain reaction (PCR) amplification of antibiotic resistance and biofilm-related genes were investigated and statistically analyzed. Staphylococcal cassette chromosome mec (SCCmec) types were analyzed by multiplex PCR, and S. aureus protein A gene typing (spa typing) was done using PCR and sequencing. Sixty-four S. aureus isolates (16.8%) were obtained from 380 medical students' mobile phones who were working in hospitals. The findings showed that 71.9% of the isolates were MRSA and 78.1% were classified as MDR. All isolates exhibited sensitivity to vancomycin and linezolid. Overall, 7.8% of the isolates displayed an inducible clindamycin resistance phenotype, while 26.7% showed resistance to mupirocin. The results indicated that 68.8% of the isolates were biofilm producers, with 7 isolates (15.9%) classified as strong producers, 22 isolates (50%) as moderate producers, and 15 isolates (34.1%) as weak producers. The most prevalent type was CC8-MRSA III/t030 (18.7%), followed by CC8-MRSA III/t037 (12.5%), CC/ST22-MSSA/t790 (10.9%), CC1-MRSA IV-t114 (9.4%), CC1-MRSA IV-t127 (7.8%), CC8-MRSA V/t064 (7.8%), CC/ST15-MSSA-t360 (7.8%), CC30-MSSA/t021(6.3%), MRSA V-t355 (6.3%), CC8-MRSA III/t421 (4.7%), CC1-MRSA V-t267 (4.7%), and CC/ST15-MSSA-t084 (3.1%). The genetic diversity and prevalent multidrug resistance indicate that the resistance situation of S. aureus recovered from mobile phones in Tehran is severe, posing a potential threat to patients, the community, and healthcare settings.

Chlorophyllin Supplementation of Medicated or Unmedicated Swine Diets Impact on Fecal Escherichia coli and Enterococci.

Considering that certain catabolic products of anaerobic chlorophyll degradation inhibit efflux pump activity, this study was conducted to test if feeding pigs a water-soluble chlorophyllin product could affect the antibiotic resistance profiles of select wild-type populations of fecal bacteria. Trial 1 evaluated the effects of chlorophyllin supplementation (300 mg/meal) on fecal E. coli and enterococcal populations in pigs fed twice daily diets supplemented without or with ASP 250 (containing chlortetracycline, sulfamethazine and penicillin at 100, 100 and 50 g/ton, respectively). Trial 2, conducted similarly, evaluated chlorophyllin supplementation in pigs fed diets supplemented with or without 100 g tylosin/ton. Each trial lasted 12 days, and fecal samples were collected and selectively cultured at 4-day intervals to enumerate the total numbers of E. coli and enterococci as well as populations of these bacteria phenotypically capable of growing in the presence of the fed antibiotics. Performance results from both studies revealed no adverse effect (p > 0.05) of chlorophyllin, antibiotic or their combined supplementation on average daily feed intake or average daily gain, although the daily fed intake tended to be lower (p = 0.053) for pigs fed diets supplemented with tylosin than those fed diets without tylosin. The results from trial 1 showed that the ASP 250-medicated diets, whether without or with chlorophyllin supplementation, supported higher (p < 0.05) fecal E. coli populations than the non-medicated diets. Enterococcal populations, however, were lower, albeit marginally and not necessarily significantly, in feces from pigs fed the ASP 250-medicated diet than those fed the non-medicated diet. Results from trial 2 likewise revealed an increase (p < 0.05) in E. coli and, to a lesser extent, enterococcal populations in feces collected from pigs fed the tylosin-medicated diet compared with those fed the non-medicated diet. Evidence indicated that the E. coli and enterococcal populations in trial 1 were generally insensitive to penicillin or chlortetracycline, as there were no differences between populations recovered without or with antibiotic selection. Conversely, a treatment x day of treatment interaction observed in trial 2 (p < 0.05) provided evidence, albeit slight, of an enrichment of tylosin-insensitive enterococci in feces from the pigs fed the tylosin-medicated but not the non-medicated diet. Under the conditions of the present study, it is unlikely that chlorophyllin-derived efflux pump inhibitors potentially present in the chlorophyllin-fed pigs were able to enhance the efficacy of the available antibiotics. However, further research specifically designed to optimize chlorophyll administration could potentially lead to practical applications for the swine industry.

Pathogenic bacteria and their antibiotic resistance profile in irrigation water in farms from Mexico

ABSTRACT The presence of antibiotic-resistant bacteria in the agro-environment is a growing international concern. In Mexico, few studies thus far have assessed the quality of water irrigation through the isolation of bacteria pathogens and the identification of antibiotic-resistant genes. Irrigation water samples obtained from rivers, wells, and ponds in different regions of Mexico were analyzed for the presence and antibiotic resistance of pathotypes of Escherichia coli, Salmonella spp., and Enterococcus spp. using selective agars and polymerase chain reaction. Two Enterococcus faecalis, one typical enteropathogenic (EPEC), and one atypical EPEC pathotypes were isolated from river water samples; two atypical EPEC and one enterotoxigenic pathotypes were isolated from pond water samples. There were no targeted pathogens detected in well water samples. All isolates were resistant to at least three antibiotics, with vancomycin being the most common; however, all isolates were sensitive to trimethoprim and ciprofloxacin. The presence of pathotypes of EPEC and ETEC and E. faecalis in water samples used for crop irrigation are a potential risk to public health because of their pathogenicity and antibiotic resistance.

The IncC and IncX1 resistance plasmids present in multi-drug resistant Escherichia coli strains isolated from poultry manure in Poland

The study describes the whole-genome sequencing of two antibiotic-resistant representative Escherichia coli strains, isolated from poultry manure in 2020. The samples were obtained from a commercial chicken meat production facility in Poland. The antibiotic resistance profile was characterized by co-resistance to β-lactam antibiotics, aminoglycosides, and fluoroquinolones. The three identified resistance plasmids (R-plasmids), pECmdr13.2, pECmdr13.3, and pECmdr14.1, harbored various genes conferring resistance to tetracyclines (tetR[A]) for, aminoglycoside (aph, aac, and aad families), β-lactam (blaCMY-2, blaTEM-176), sulfonamide (sul1, sul2), fluoroquinolone (qnrS1), and phenicol (floR). These plasmids, which have not been previously reported in Poland, were found to carry IS26 insertion elements, the intI1-integrase gene, and conjugal transfer genes, facilitating horizontal gene transfer. Plasmids pECmdr13.2 and pECmdr14.1 also possessed a mercury resistance gene operon related to transposon Tn6196; this promotes plasmid persistence even without antibiotic selection pressure due to co-selection mechanisms such as co-resistance. The chicken manure–derived plasmids belonged to the IncX1 (narrow host range) and IncC (broad host range) incompatibility groups. Similar plasmids have been identified in various environments, clinical isolates, and farm animals, including cattle, swine, and poultry. This study holds significant importance for the One Health approach, as it highlights the potential for antibiotic-resistant bacteria from livestock and food sources, particularly E. coli, to transfer through the food chain to humans and vice versa.

Temporal evolution of bacterial species and their antimicrobial resistance characteristics in wound infections of war-related injuries in Ukraine from 2014 to 2023

This study continues surveillance of antimicrobial resistance associated with combat injuries in Ukraine. To compare species composition, antibiotic resistance profiles, and emergence of new resistance genes between 2014-2020 and 2022-2023. Retrospective multicentre microbiological survey in Ukrainian hospitals. Antibiotic susceptibility, whole genome sequencing, and MLST typing were conducted on 154 organisms obtained from 125 casualties from 2022-2023. The data reveals a predominance of gram-negative bacteria, particularly Acinetobacter baumannii (35.7%), Pseudomonas aeruginosa (14.9%), and Klebsiella pneumoniae (20.7%). High levels of carbapenem resistance was observed among A. baumannii (meropenem 72,2% [(39/54) 95% CI 58.4-83.5], imipenem 66.7% [(36/54) 95% CI 52.5-78.9]), Klebsiella (meropenem 90.6% [(29/32) 95% CI 75.0-98.0], imipenem 81.2% [(26/32) 95% CI 63.6-92.8]), and P. aeruginosa (meropenem 47.8% [(11/23) 95% CI 26.8-69.4], imipenem 60.8% [(14/23) 95% CI 38.5-80.3]) strains. A. baumannii ST-78 and ST-400 were prevalent from 2014 to 2020, while 5 strains of ST-1077 were newly identified. Pseudomonas aeruginosa strains showed diversity across 16 sequence types (STs), with ST-773 increasing in frequency and new STs emerging, but lacking carbapenemase genes. K. pneumoniae exhibited increased genetic diversity over time, with three STs from 2014 to 2020 and six new STs, including blaNDM-1, blaOXA-48, and blaKPC2 carriers, in recent years. There is a growing prevalence of multidrug resistant isolates from globally distributed sequence types.

Retrospective study on the occurrence of Salmonella serotypes in veterinary specimens of Atlantic Canada (2012-2021).

This study aimed to summarize the frequency and the antimicrobial susceptibility profiles of the Salmonella serotypes identified from the specimens of companion animals, livestock, avian, wildlife and exotic species within Atlantic Canada. The retrospective electronic laboratory data of microbiological analyses of a selected subset of samples from 03 January 2012 to 29 December 2021 submitted from various animal species were retrieved. The frequency of Salmonella serotypes identified, and their antimicrobial susceptibility results obtained using the disk diffusion or broth method were analysed. The test results were interpreted according to the Clinical and Laboratory Standards Institute standard. The Salmonella serotypes were identified by slide agglutination (Kauffman-White-Le-Minor Scheme) and/or the Whole Genome Sequencing for the Salmonella in silico Serovar Typing Resource-based identification. Of the cases included in this study, 4.6% (n=154) had at least one Salmonella isolate, corresponding to 55 different serovars. Salmonella isolation was highest from exotic animal species (n=40, 1.20%), followed by porcine (n=26, 0.78%), and canine (n=23, 0.69%). Salmonella subsp. enterica serovar Typhimurium was predominant among exotic mammals, porcine and caprine samples, whereas S. Enteritidis was mostly identified in bovine and canine samples. S. Typhimurium of porcine origin was frequently resistant (>70.0%) to ampicillin. In contrast, S. Typhimurium isolates from porcine and caprine samples were susceptible (>70.0%) to florfenicol. S. Oranienburg from equine samples was susceptible to chloramphenicol, but frequently resistant (>90.0%) to azithromycin. In avian samples, S. Copenhagen was susceptible (>90.0%) to florfenicol, whereas Muenchen was frequently resistant (>90.0%) to florfenicol. S. subsp. diarizonae serovar IIIb:61:k:1,5 of ovine origin was resistant (50.0% isolates) to sulfadimethoxine. No significant changes were observed in the antibiotic resistance profiles across the study years. This report provides data for surveillance studies, distribution of Salmonella serotypes and their antimicrobial resistance among veterinary specimens of Atlantic Canada.

Distribution Patterns and Antibiotic Resistance Profiles of Bacterial Pathogens Among Patients with Wound Infections in the Jiaxing Region from 2021 to 2023.

To systematically assess the distribution and antimicrobial susceptibility of pathogens in wound infections, and analyze risk factors associated with multidrug resistance (MDR). Retrospectively analyzing Jiaxing-region medical records between January 2021 and December 2023, we identified a cohort of 461 wound infection patients. Cultures were grown on various agars, with bacteria identified via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. The antimicrobial susceptibility of the organisms were conducted by VITEK 2 system, Kirby-Bauer disk diffusion method and Epsilometer test. Statistical Package for the Social Sciences (SPSS) version 22 was used for statistical analysis. Multivariable logistic regression models were developed to pinpoint risk factors for multidrug-resistant organism (MDRO) infections and predict occurrences. From 461 patients, 549 bacterial pathogens were isolated, predominantly consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, and Enterococcus faecalis. Vancomycin, linezolid, and tigecycline maintained their efficacy against Staphylococcus aureus and Enterococcus species, while Pseudomonas aeruginosa demonstrated sensitivity to aminoglycosides. Conversely, Escherichia coli exhibited high amoxicillin resistance (85.4%). More than half of the isolates were resistant to levofloxacin, ceftriaxone, cotrimoxazole, and gentamicin, with Acinetobacter baumannii strains showing considerable resistance (65.8-68.4%) to advanced cephalosporins and carbapenems. Within this group, 58 MDROs were detected, primarily originating from Burn Plastic Surgery, Emergency, and Intensive Care Unit (ICU) departments. Multivariate logistic regression identified hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and exposure to multiple antibiotic classes as independent risk factors for MDRO wound infections. Based on these findings, a predictive model for MDRO occurrence in wounds was constructed, which had a sensitivity of 0.627, specificity of 0.933, and an Area Under the Curve (AUC) of 0.838. Staphylococcus aureus and Pseudomonas aeruginosa dominated in wound infections with differential antibiotic resistance. Independent risk factors included hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and polyantibiotic use. We urge prioritizing culture, susceptibility tests, and personalized antibiotic strategies to address MDRO risks and improve wound infection management specificity and efficacy.

Salmonella Isolated From Raw Chicken Meats at Selected Slaughterhouses in Peninsular Malaysia; Their Antibiotic Resistance Profiles and Biofilm Formation on Nutrient-Limited Media

Salmonella is one of the pathogens responsible for foodborne diseases. Antibiotic resistance of Salmonella, particularly multidrug-resistant (MDR) strains have emerged and are becoming more prevalent, which is a very serious issue worldwide. This study sought to determine the antibiotic resistance profiles of Salmonella isolated from raw chicken meats, which were collected at selected slaughterhouses in Peninsular Malaysia and evaluating its biofilm-forming capability on surfaces. Antibiotic resistance of 135 Salmonella isolates against 12 antibiotics were investigated via disk diffusion method. The biofilm-forming ability of the isolates was evaluated by crystal violet staining using two media; a tryptic soy broth (TSB) and a 1/20 TSB with incubation periods of 24 and 48 h at 37 °C. A total of 118 strains of Salmonella showed higher resistance to erythromycin (87.41%), followed by tetracycline (85.19%;); 93 of the isolates (68.88%) were multi-drug resistant. A greater quantity of Salmonella was able to produce biofilm when grown in 1/20-TSB (90.37%) compared to the growth in TSB (88.15%), respectively. The findings in this study showed high prevalence, antibiotic resistance, and the biofilm forming ability of Salmonella strains isolated from raw chicken meats, suggesting that effective measures are required to ensure food safety in the poultry industry.

Assessment of Antibiotic Resistance Profiles of Pathogenic Bacteria Isolates from Migratory Birds in the River Ravi Stopover Site

Assessment of Antibiotic Resistance Profiles of Pathogenic Bacteria Isolates from Migratory Birds in the River Ravi Stopover Site

Microbiological Quality and Antibiotic Resistance of Home-made and Commercial Complementary Foods: A Comparative Pilot Study

Objective The study aims to compare the microbiological quality and antibiotic resistance profiles of homemade and commercial infant foods. Materials and Methods: A variety of both homemade and commercially available infant foods were collected and analyzed for microbial content and antibiotic resistance patterns using standard microbiological methods. Findings: The study observed that prolonged storage significantly impacted the microbiological quality of infant foods. It was found that both homemade and commercial products showed an increase in microbial growth over time. Notably, the presence of pathogenic bacteria was detected in several samples, indicating potential health risks for infants. Conclusion: The study highlights the need for better awareness and standards in the preparation and selection of infant foods, considering the microbiological safety and emerging antibiotic resistance issues.

Virulence Determinants of Buffalo Mastitis Originated Streptococcus agalactiae Isolates

Streptococci as a cause of mastitis have become the major concern to the dairy industry worldwide due to huge economic losses. Streptococcus agalactiae is a major contagious mastitis pathogen and continues to be a major cause of mastitis in dairy cattle and buffaloes. The aim of the study was to investigate the virulence determinants of S. agalactiae strains isolated from buffalo milk. Within the scope of the study, 24 S. agalactiae isolates from buffalo mastitis were examined. Biofilm production of isolates was investigated phenotypically by CRA method. It was observed that 18 (75%) isolates were positive for biofilm production. The presence of hylB, fnbB, scpB and spb1 virulence genes in S. agalactiae isolates were investigated by PCR. It was determined that 19 (79.17%) of the isolates were positive for scpB and 6 (25%) for fnbB virulence genes. None of the isolates were found to contain hylB and spb1 virulence genes. The antibiotic resistance profiles of the isolates among kanamycin, ampicillin, enrofloxacin, erythromycin, tetracycline, trimethoprim-sulfamethoxazole antibiotic discs were determined by Kirby Bauer Disc Diffusion Method. Resistance were evaluated as % 41.7, % 45.9, % 25, % 12.5, % 20.9, and % 33.3, respectively. RAPD-PCR patterns of all isolates were determined using the ERIC-2 primer. The dendrograms of the RAPD patterns were plotted with the UPGMA method. It was determined that the isolates showed similarity between 59-95%. In conclusion, the research confirms the prevalence of various virulence genes in S. agalactiae isolated from buffalo mastitis. Further studies are therefore necessary to determine the molecular epidemiology and variability of S. agalactiae isolated from buffaloes, with the aim of improving mastitis control programs with regard to S. agalactiae.

Six-year evaluation of device-associated nosocomial infections in intensive care units.

Invasive device-associated nosocomial infections commonly occur in intensive care units (ICUs). These infections include intravascular catheter-related bloodstream infection (CRBSI), ventilator-associated pneumonia (VAP), and catheter-associated urinary tract infection (CAUTI). This study aimed to evaluate the factors associated with invasive device-associated nosocomial infections based on the underlying diseases of the patients and antibiotic resistance profiles of the pathogens causing the infections detected in the ICU in our hospital over a five-year period. Invasive device-associated infections (CRBSI, VAP, and CAUTI) were detected retrospectively by the laboratory- and clinic-based active surveillance system according to the criteria of the US Centers for Disease Control and Prevention (CDC) in patients hospitalized in the ICU of the tertiary hospital between 1 January 2018 and 30 June 2023. A total of 425 invasive device-associated nosocomial infections and 441 culture results were detected (179 CRBSI, 176 VAP, 70 CAUTI). Out of them, 57 (13.4%) patients had hematological malignancy, 145 (34.1%) had solid organ malignancy, and 223 (52.5%) had no histopathologic diagnosis of any malignancy. An increase in extended-spectrum beta lactamase (ESBL) and carbapenem resistance in pathogens was detected during the study period. Antibiotic resistance of the Gram-negative bacteria associated with invasive device-associated infections increased during the study period. Antimicrobial stewardship will reduce rates of nosocomial infections, reduce mortality, and shorten hospital stay. Long-term catheterization and unnecessary antibiotic use should be avoided.

Occurrence, antibiotic resistance profile and molecular characterization of Staphylococcus aureus isolated from pork and chicken meat sold in Gia Lam District, Hanoi City

Staphylococcus aureus (S. aureus) is one of the most important zoonotic pathogens causing diseases for both humans and animals. Food, particularly meat, is considered the main vector for the transmission of this bacterium to humans. The findings of this study indicate that S. aureus contamination rates of pork and chicken meat samples were 24% and 16%, respectively. S. aureus isolates showed the highest resistance rates to penicillin (90%) and ampicillin (75%), and the lowest resistance to meropenem (5%) and linezolid (10%). Notably, 100% of the isolates were resistant to at least one antibiotic, and 65% were classified as multidrug-resistant strains. The results of molecular characterization revealed that all S. aureus isolates were positive for spa and 15% carried mecA. The detection rates of sea, seb, sed, and see genes were 20%, 5%, 15%, and 5%, respectively.

Antibiotic Resistance Profile of Bacteria Isolated from Wastewater Treatment Plants and Urban Stream of Ganges River in Northern India

Antibiotic Resistance Profile of Bacteria Isolated from Wastewater Treatment Plants and Urban Stream of Ganges River in Northern India

EVALUATION OF PATIENTS WITH COMPLICATED URINARY TRACT INFECTIONS: A SINGLE CENTRE EXPERIENCE

Aim: Urinary tract infection (UTI) is one of the most common infectious diseases and broad-spectrum antibiotics are commonly used for its treatment. Increased use of these antibiotics is leading to a rapid increase in antibiotic resistance rates in the treatment of UTI. In this study, we aimed to determine the causative agents and antibiotic resistance profile of these agents in patients with complicated UTIs. Material – Methods:We retrospectively evaluated the inpatients with complicated UTI in our clinic within one year. Results: The study included 154 patients (69 (44.8%) were male, 85 (55.2%) were female with a mean age of 68.9±15.3 years. The most common comorbidities were essential hypertension (n:87, 56.5%), type 2 diabetes mellitus (n:74, 48.1%), and cerebrovascular disease/coronary artery disease (n:49, 31.8%). The most common UTI agents were E.coli (46.1%), Klebsiella spp (14.9%), and Candida spp (7.1%). While 42.6% of these E.coli produced extended spectrum beta-lactamase (ESBL), 13% of Klebsiella spp produced ESBL. The frequency of ciprofloxacin resistance was statistically significantly higher in ESBL-positive bacteria compared to ESBL-negative bacteria (84.8%/35.9%, p

Detection of hidden antibiotic resistance through real-time genomics

Real-time genomics through nanopore sequencing holds the promise of fast antibiotic resistance prediction directly in the clinical setting. However, concerns about the accuracy of genomics-based resistance predictions persist, particularly when compared to traditional, clinically established diagnostic methods. Here, we leverage the case of a multi-drug resistant Klebsiella pneumoniae infection to demonstrate how real-time genomics can enhance the accuracy of antibiotic resistance profiling in complex infection scenarios. Our results show that unlike established diagnostics, nanopore sequencing data analysis can accurately detect low-abundance plasmid-mediated resistance, which often remains undetected by conventional methods. This capability has direct implications for clinical practice, where such “hidden” resistance profiles can critically influence treatment decisions. Consequently, the rapid, in situ application of real-time genomics holds significant promise for improving clinical decision-making and patient outcomes.

The Presence and Antibiotic Resistance of Non-O157 STEC on Lamb Carcasses

There is an increasing trend in the prevalence of Hemolytic Uremic Syndrome (HUS) both in Türkiye and in the world. HUS might be caused by Shiga toxin (Stx)-producing Escherichia coli (STEC) O157 and strains of non-O157 STEC. The feces and fleece of lambs, and non-hygienic conditions present in the lamb slaughtering process are the main sources for STEC contaminations of lamb carcasses. In this study, the prevalence of STEC on lamb carcasses and, as an important global public health issue, the antibiotic resistance profiles of STEC strains isolated were aimed to be determined. The presence of stx was considered as STEC indicator. 16% of the carcasses (8/50) were found to be contaminated by E. coli. The analysis showed that none of the strains isolated were O157 serotype. But, 5 out of 8 strains isolated carried stx1 and stx2 genes so they were identified as non-O157 cytotoxigenic E. coli. Antibiotic resistance profiles of the isolates were determined by using Kirby Bauer method. All of the isolates were found to be resistant at least one antibiotics investigated, and as the most resistance rate found 87.5% of the isolates were resistant to both gentamycin and pefloxacine. In addition, 75% of the isolates were multidrug resistant (MDR), and overall MAR (Multi Antimicrobial Resistant) index of isolates was 0.4. As a result, STEC contamination on lamb carcasses was considered to be a risk for both children and adults for HUS, and high antibiotic resistance of the isolates observed also increased the public health hesitations. Reassessment of the slaughtering process based on the HACCP (Hazard Analysis and Critical Control Points) requirements and taking necessary actions/measures to control cross contaminations are thought to be crucial steps to reduce pathogenic bacteria incidence in food chain.

First Report on the Occurrence and Antibiotic Resistance Profile of Colistin-Resistant Escherichia coli in Raw Beef and Cow Feces in Vietnam.

Colistin-resistant Escherichia coli (COE) has been recently recognized as a serious threat to animal and human health. This study aimed to determine the prevalence and antibiotic resistance profile of COE isolated from raw beef and cow feces in Vietnam. Our results showed that 16% (16/100) and 32% (32/100) of raw beef and cow feces samples were positive for COE, respectively. A total of 48 COE strains were isolated, with 16 originating from raw beef and 32 from cow feces samples. The antibiotic susceptibility test revealed that the COE isolates were highly resistant to ampicillin, tetracycline, florfenicol, trimethoprim/sulfamethoxazole, streptomycin, and nalidixic acid, with resistance rates ranging from 66.67% to 87.5%. In addition, 87.5% of the isolates were identified to be multidrug-resistant strains. Further molecular characterization indicated that all COE isolates carried the mcr-1 gene, with 16 of them also harboring blaCTX-M-55 genes. Taken together, the findings in this study demonstrate that raw beef and cow feces are important sources of COE, which can be potentially transmitted to humans through the food chain.

Investigation of prevalence and antimicrobial resistance of Salmonella in pet dogs and cats in Turkey.

Although salmonellosis is considered to be a foodborne zoonotic disease, pets can play a significant role in the dissemination of antimicrobial-resistant Salmonella organisms to humans because of close contact with their owners. To determine the prevalence, risk factors, virulence factors, serotypes, and antimicrobial resistance profile of Salmonella in pet dogs and cats in Turkey and to assess the public health risk. Furthermore, to perform macroscopic comparison of lactic acid bacteria (LAB) in Salmonella-positive and Salmonella-negative animals. International Standards Organization (ISO) 6579-1:2017 and Food and Drug Administration (FDA) methods were used to compare the effectiveness of culture methods in the identification of Salmonella in 348 rectal swabs. Positive isolates were serotyped using the slide agglutination method according to the White-Kauffmann-Le Minor scheme and the presence of virulence genes (invA and stn) were evaluated by polymerase chain reaction (PCR). Antimicrobial activity was tested by Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Salmonella prevalence was 5.73% (9/157) in dogs and 0.0% (0/191) in cats. Eight (8/9) isolates were cultured with the ISO method and 5 (5/9) isolates were cultured with the FDA method. Macroscopic results revealed that Salmonella agents had no effect on LAB. Three different serotypes were detected and all isolates were positive for virulence genes. Antibiotic resistance profiling indicated that 11.1% of the isolates were MDR and the highest resistance was found for ciprofloxacin. MDR-resistant S. Virchow and carbapenem-resistant S. Enteritidis were detected from dog isolates. There was a significant difference between raw meat consumption and Salmonella carriage (p < 0.01). Dogs could be potential carriers of Salmonella infection. The isolation of Salmonella in healthy dogs instead of dogs suffering from diarrhoea indicates that attention should be paid to asymptomatic carriage. The emergence of resistance among zoonotic Salmonella isolates poses a significant threat to public health.

Metagenomic Investigation of the Short-Term Temporal and Spatial Dynamics of the Bacterial Microbiome and the Resistome Downstream of a Wastewater Treatment Plant in the Iskar River in Bulgaria.

Waste Water Treatment Plants (WWTP) aim to reduce contamination in effluent water; however, studies indicate antimicrobial resistance genes (ARGs) persist post-treatment, potentially leading to their spread from human populated areas into the environment. This study evaluated the impact of a large WWTP serving 125,000 people on the Iskar River in Bulgaria, by characterizing the spatial and short-term temporal dynamics in bacterial community dynamics and resistance profiles of the surface water. Pairs of samples were collected biweekly on four dates from two different locations, one about 800 m after the WWTP effluents and the other 10 km downstream. Taxonomic classification revealed the dominance of Pseudomonodota and Bacteriodota, notably the genera Flavobacterium, Aquirufa, Acidovorax, Polynucleobacter, and Limnohabitans. The taxonomic structure corresponded with both lentic and lotic freshwater habitats, with Flavobacterium exhibiting a significant decrease over the study period. Principal Coordinate Analysis revealed statistically significant differences in bacterial community composition between samples collected on different dates. Differential abundance analysis identified notable enrichment of Polynucleobacter and Limnohabitans. There were shifts within the enriched or depleted bacterial taxa between early and late sampling dates. High relative abundance of the genes erm(B), erm(F), mph(E), msr(E) (macrolides); tet(C), tet(O), tet(W), tet(Q) and tet(X) (tetracyclines); sul1 and sul2 (sulphonamides); and cfxA3, cfxA6 (beta-lactams) were detected, with trends of increased presence in the latest sampling dates and in the location closer to the WWTP. Of note, genes conferring resistance to carbapenems blaOXA-58 and blaIMP-33-like were identified. Co-occurrence analysis of ARGs and mobile genetic elements on putative plasmids showed few instances, and the estimated human health risk score (0.19) according to MetaCompare2.0 was low. In total, 29 metagenome-assembled genomes were recovered, with only a few harbouring ARGs. This study enhances our understanding of freshwater microbial community dynamics and antibiotic resistance profiles, highlighting the need for continued ARGs monitoring.