Intestinal Tract of Broiler Chickens as a Reservoir of Potentially Pathogenic Curli Producing ESβL Escherichia coli

Abstract

Commensal enteric E. coli in healthy birds have virulence genes which enable them to be pathogenic under suitable conditions. A total of 80 E. coli isolates recovered from the intestine of healthy broiler chickens were tested for some virulence characters based on Congo red (CR) binding assay, hemolysis, serum resistance and biofilm formation. The virulent isolates were identified serologically by slide agglutination test and O1 (25%) was the most prevalent enteric E. coli serogroups. The antibiogram profile revealed that all isolates were resistant to at least three different antibiotics. Amoxicillin and ceftriaxone showed the highest resistance (100%), followed by lincomycin, kanamycin, streptomycin and sulfamethoxazole-trimethoprim (96%). In contrast, 80 and 52% of the isolates were sensitive to amikacin and fosfomycin, respectively. The PCR revealed that all isolates harbored virulence genes (int1, ampC, fimH, iss and eaeA), in addition to 91, 16 and 16% of isolates had mcr1, pic and tsh genes, respectively, proving that avian intestinal reservoir of potentially pathogenic curli producing ESβL Escherichia coli.