The aim of this study was to investigate the presence of shiga toxin-producing Escherichia coli (STEC) and atypical enteropathogenic Escherichia coli (aEPEC) in frozen chicken carcasses sold at stores in southern Brazil. Typical E. coli colonies were enumerated in 246 chicken carcasses, and the presence of stx1, stx2, eae genes was investigated in their rinse liquid and in E. coli strains isolated from those carcasses.Strains of E. coli were also investigated for the presence of bfp gene. A median of 0.6 cfu.g -1 (ranging from <0.1 to 242.7 cfu.g -1 ) of typical E. coli colonies was found in the carcasses. Shiga toxin-encoding genes (stx1 and stx2) were not detected, indicating that the chicken carcasses were negative for STEC. The intimin protein gene (eae) was detected in E.coli isolated from 4.88% of the carcasses; all tested strains were negative for the bfp gene and were classified as aEPEC. Twenty-two aEPEC strains were tested for resistance to ten antimicrobials and subjected to macrorestriction (PFGE). All the tested aEPEC strains were fully susceptible to cephalosporins, ciprofloxacin and colistin. Resistance to sulfonamide (65%), ampicillin (55%), tetracycline (50%) and gentamicin (45%) were the most frequent. The PFGE profile demonstrated a low level of similarity among the resistant strains, indicating that they were epidemiologically unrelated. The results indicate that aEPEC strains can contaminate chicken meat, and their association with strains implicated in human diarrhea needs to be further investigated.
Knowledge about antimicrobial resistance in Salmonella is relevant due to its importance in foodborne diseases. We gathered data obtained over 16 years in the southern Brazilian swine production chain to evaluate the temporal evolution of halo for carbapenem, and the MIC for third-generation cephalosporins, fluoroquinolone, and polymyxin in 278 Salmonella Derby and Typhimurium isolates. All antimicrobial resistance assays were performed in accordance with EUCAST. To assess the diameter halo, we used a mixed linear model, and to assess the MIC, an accelerated failure time model for interval-censored data using an exponential distribution was used. The linear predictor of the models comprised fixed effects for matrix, serovar, and the interaction between year, serovar, and matrix. The observed halo diameter has decreased for ertapenem, regardless of serovars and matrices, and for the serovar Typhimurium it has decreased for three carbapenems. The MIC for ciprofloxacin and cefotaxime increased over 16 years for Typhimurium, and for Derby (food) it decreased. We did not find evidence that the MIC for colistin, ceftazidime, ciprofloxacin (Derby), or cefotaxime (food Typhimurium and animal Derby) has changed over time. This work gave an overview of antimicrobial resistance evolution from an epidemiological point of view and observed that using this approach can increase the sensitivity and timeliness of antimicrobial resistance surveillance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.