Antimicrobial susceptibility and genetic profiles of Escherichia coli isolated from poultry hatcheries in the state of Rio Grande do Sul, Brazil.

Escherichia coli is widely distributed in human and animals as part of commensal microbiota, but some isolates can act as major pathogens causing severe diseases. Data regarding the characterization of E. coli isolated from hatchery is limited. Extensive genetic similarity among isolates has been previously reported, including similar virulence and antimicrobial resistance genes, which make it difficult to differentiate between pathogenic and commensal bacteria. The aim of this study was to characterize 84 E. coli isolates from four hatcheries in Rio Grande do Sul state (Brazil) for antimicrobial susceptibility, detection of multidrug resistance (MDR) and extended-spectrum β-lactamases (ESBL) isolates, and phylogenetic groups. Most antimicrobial agents presented moderate (20-50%) or high (> 50%) resistance rates, and 58 phenotypic resistance profiles were observed. A total of 51.19% and 20.24% of isolates were classified as MDR and ESBL, respectively. The majority of the isolates (80.95%) were classified in the pathogenic phylogroups (B2 and D), regardless the hatchery establishment. The hatchery did not influence in any of the results. The results demonstrate the high antibiotic resistance demonstrated by E. coli isolated from hatcheries in southern Brazil. The dissemination of pathogenic isolates in all establishments evaluated is a matter of particular concern. In this context, the results found in this study are important and may be the first step on monitoring pathogenicity and antimicrobial resistance fluctuation in Brazilian hatcheries.