Virulence gene profiles, antimicrobial resistance and phylogenetic groups of fecal Escherichia coli strains isolated from broiler chickens in Algeria

The objective of the study was to determine the virulence and antimicrobial resistance traits of 100 fecal E. coli strains isolated from clinically healthy chickens in Algeria. Most of isolates belonged to phylogroups A (45%) and B1 (37%) and showed a great diversity in DNA profiles. The genes fimH, tsh, entB, iutA, irp2, fyuA, iroN, sitA, etsA, etsB, eitA, iss, traT, ompT, hlyF, vat, ibeA, cvaA, cvaB5; cvaB3; cvaC, cma and cbi were detected. Combinations of virulence genes defined 67 virulence profiles. High resistance rates (62-97%) were noted for amoxicillin, amoxicillin-clavulanic acid, cefazolin, fluoroquinolones, tetracycline, trimethoprim, sulfonamides and sulfamethoxazole/ trimethoprim, and 93% of strains were multidrug-resistant. Combinations of resistance phenotypes defined 59 resistance patterns. The genes bla(TEM), bla(SHV), bla(CTX-M-1),tetA, tetB, qnrB, qnrS1, sul1, sul2, sul3, dfrA1,dfrA7, dfrA12 and dfrA14 were identified and class 1 integrons were detected in 49% of isolates. A rate of 37% of strains was resistant to mercury, with the presence of merA gene. The study reports the presence in the avian strains isolated from fecal swabs of virulence genes of plasmid origin characteristic of ExPEC strains associated with high resistance to first-line antibiotics and class 1 integrons, this augurs a risk for human and animal health.