Antimicrobial resistance and virulence factors in chicken-derived E. coli isolates

Abstract

A total of 180 samples were taken from diseased and freshly dead broiler chickens of various ages from various farms in El-Minya and Beni-Suef governorates and transferred to the lab for bacterial isolation and further molecular examination targeting E. coli. The results showed that 91 of 180 samples (50.6%) tested positive for E. coli. The   prevalence of some in vitro virulence markers of avian pathogenic E. coli was Congo red binding (CRB) (95.6% positivity) and moderate to strong biofilm production (92%). On 5% sheep blood agar, (67%) of examined isolates showed alpha hemolysis, while (27%) showed gamma hemolysis  and (5.5%) showed beta hemolysis. All the tested isolates exhibited a multidrug resistance (MDR) pattern. E. coli isolates demonstrated various degrees of resistance against, amoxicillin–sulbactam (82%) followed by streptomycin (76%), cefotaxime and trimethoprim/sulphamethoxazole (73%), tetracycline and ciprofloxacin (68%), chloramphenicol (66%), cefaclor (65%), cefixime (62%) respectively. Five MDR selected isolates were examined using PCR. The intended virulence genes were iss, tsh, fimH, and iroN genes. The genes iss and fimH were detected in all of the isolates investigated, whereas iroN was present in four isolates but tsh was found in only one isolate.