Chickens continue to be an important reservoir of zoonotic multidrug-resistant illnesses. Antimicrobial resistance correlated with colistin has emerged as a critical concern worldwide in the veterinary field and the public health sector. The current study investigated the prevalence of multidrug-resistant avian pathogenic Escherichia coli among chicken farms in three Egyptian governorates, focusing on colistin resistance assessment. A total of 56 Escherichia coli isolates were recovered out of 120 pooled samples obtained from diseased chicken broilers (46.7%). The E. coli isolates were serotyped to nine different serotypes; the highest incidence was for O125 (n = 18). The E. coli isolates demonstrated multidrug-resistant patterns against 10 antibiotics, especially clindamycin, tetracycline, streptomycin and ampicillin, by 100, 100, 96.4 and 92.9%, respectively. On the other hand, colistin resistance was 41.1% using AST. All E. coli isolates displayed positive colistin resistance growth on chromogenic medium, but only 25% represented this positivity via MIC estimation and Sensititre kit. PCR results revealed that all isolates harbored mcr-1, but no isolates harbored the other 2–5 mcr genes. In conclusion, the study demonstrated the emergence of multidrug-resistant, especially colistin-resistant, E. coli among chicken broiler flocks, and mcr-1 is the master gene of the colistin resistance feature.

A total of (120) samples of aborted foeti, vaginal discharage and Placenta were collected from (70) aborted ewes and (50) aborted she goats from Menoufiea Governorate for bacteriological and mycological examination. Swabs from stomach and intestinal contents of aborted foeti as well as liver , spleen, and lungs were collected. The bacteriological examination of aborted foeti, vaginal discharage and Placenta of aborted sheep revealed the isolation of