Recent studies indicated that some highly resistant strains of E. coli can be common contaminants of broiler meat, and resistance determinants can be of importance for the food production and human health. However, much less is known about their virulence determinants, and detailed genetic analyses of antimicrobial resistance and virulence are especially missing in E. coli from newly hatched broiler chicks.
We aimed to provide a comparative description of antimicrobial resistance and virulence of E. coli isolates from young chicks from farms and from fresh broiler meat.
A total of 70 E. coli isolates characterized here derived from different poultry sources: raw meat (28), young chicks from farms (represented by 11 intestinal- and 11 extraintestinal strains) and 20 E. coli isolates from newly hatched chicks. Resistance and virulence genotyping was performed using high throughput PCR microarray systems, AMR05 and Ec03 respectively.
The tetra-resistant phenotype of streptomycin-nalidixic acid-sulfonamide-tetracycline commonly occured among E. coli strains from different chicken sources. The antimicrobial resistance genotype of E. coli strains from raw meet showed the highest similarity with the intestinal strains from young chicks. The high prevalence of antimicrobial resistance genes related to the flexible genome indicate the commonly high distribution of certain mobile genetic elements in poultry E. coli. Obviously, the predominance of the virulence genes in the extraintestinal E. coli strains was not surprising, however some of the virulence genes (iss, tsh, iutA) showed high prevalence in commensal isolates from newly hatched chicks and from the meat.
Results indicate that E. coli from newly hathed chicks may represent a reservoir for multiresistance and virulence for both pathogenic and commensal E. coli strains of young chicks and of poultry meat.
Acknowledgement: This work was supported by EU FP7 Collaborative Project PROMISE. Ama Szmolka is a holder of János Bolyai Research Scholarship of the HAS
