Resistance to extended-spectrum cephalosporins in Escherichia coli and Salmonella enterica isolated from food-producing animals: Ecological study from selected national surveillance programs

Prevalence, serotype, antimicrobial susceptibility, contamination factors, and control methods of Salmonella spp. in retail fresh fruits and vegetables: A systematic review and meta-analysis

This research presents a comprehensive review of Salmonella presence in retail fresh fruits and vegetables from 2010 to 2023, utilizing data from recognized sources such as PubMed, Scopus, and Web of Science. The study incorporates a meta-analysis of prevalence, serovar distribution, antimicrobial susceptibility, and antimicrobial resistance genes (ARGs). Additionally, it scrutinizes the heterogeneous sources across various food categories and geographical regions The findings show a pooled prevalence of 2.90% (95% CI: 0.0180-0.0430), with an increase from 4.63% in 2010 to 5.32% in 2022. Dominant serovars include S. Typhimurium (29.14%, 95% CI: 0.0202-0.6571) and S. Enteritidis (21.06%, 95% CI: 0.0181-0.4872). High resistance rates were noted for antimicrobials like erythromycin (60.70%, 95% CI: 0.0000-1.0000) and amoxicillin (39.92%, 95% CI: 0.0589-0.8020). The most prevalent ARGs were blaTEM (80.23%, 95% CI: 0.5736-0.9692) and parC mutation (66.67%, 95% CI: 0.3213-0.9429). Factors such as pH, water activity, and nutrient content, along with external factors like the quality of irrigation water and prevailing climatic conditions, have significant implications on Salmonella contamination. Nonthermal sterilization technologies, encompassing chlorine dioxide, ozone, and ultraviolet light, are emphasized as efficacious measures to control Salmonella. This review stresses the imperative need to bolster prevention strategies and control measures against Salmonella in retail fresh fruits and vegetables to alleviate related food safety risks.

Beta-lactamase genes in bacteria from food animals, retail meat, and human surveillance programs in the United States from 2002 to 2021

The spread of beta-lactamase-producing bacteria is a global public-health concern. This study aimed to explore the distribution of beta-lactamases reported in three sampling sources (cecal, retail meat, and human) collected as part of integrated surveillance in the United States. We retrieved and analyzed data from the United States National Antimicrobial Resistance Monitoring Systems (NARMS) from 2002 to 2021. A total of 115 beta-lactamase genes were detected in E. coli, Salmonella enterica, Campylobacter, Shigella and Vibrio: including 35 genes from cecal isolates, 32 genes from the retail meat isolates, and 104 genes from the human isolates. Three genes in E. coli (blaCMY-2,blaTEM-1A, and blaTEM-1B), 6 genes in Salmonella enterica (blaCARB-2, blaCMY-2, blaCTXM-65, blaTEM-1A, blaTEM-1B, and blaHERA-3), and 2 genes in Campylobacter spp. (blaOXA-61 and blaOXA-449) have been detected across food animals (cattle, chicken, swine, and turkey) and humans over the study period. blaCTXM-55 has been detected in E. coli isolates from the four food animal sources while blaCTXM-15 and blaCTXM-27 were found only in cattle and swine. In Salmonella enterica, blaCTXM-2, blaCTXM-9, blaCTXM-14, blaCTXM-15, blaCTXM-27, blaCTXM-55, and blaNDM-1 were only detected among human isolates. blaOXAs and blaCARB were bacteria-specific and the only beta-lactamase genes detected in Campylobacter spp. and Vibrio spp respectively. The proportions of beta-lactamase genes detected varies from bacteria to bacteria. This study provided insights on the beta-lactamase genes detected in bacteria in food animals and humans in the United States. This is necessary for better understanding the molecular epidemiology of clinically important beta-lactamases in one health interface.

Characterization, estimation of virulence and drug resistance of diarrheagenic escherichia coli (DEC) isolated from Tibetan pigs

In this study, we collected feces of Tibetan piglets from Nyingchi area for isolation, culture, identification, virulence gene analysis and drug resistance analysis of Escherichia Coli. The results demonstrated a 41.3% isolation rate of Diarrheagenic Escherichia Coli from Tibetan pigs with the main phylogenetic groups: group A (68.6%) and group B2 (15.7%). Typical E.coli accounted for 76.5%. The highest detection rates of porcine virulence genes were E.coli heat-resistant enterotoxin STb (58.82%) and F107 fimbrial subunit (23.53%). The highest detection rates of virulence genes from Tibetan pigs were fimC (80.39%) and ompA (76.47%). A drug sensitivity test showed that Diarrheagenic Escherichia Coli from Tibetan pigs had high drug resistance rates to mezlocillin, doxycycline and gentamicin. This study comprehensively analyzed the species composition, virulence and drug resistance of Diarrheagenic Escherichia Coli from Tibetan pigs, which provided a clearer and more targeted idea for the prevention and treatment of yellow and white dysentery in Tibetan pigs in the future.