AVIAN PATHOGENIC ESCHERICHIA COLI IN DISEASED CHICKENS FROM COMMERCIAL FARMS IN NORTHWEST, NIGERIA

Abstract

Avian colibacillosis, which is caused by avian pathogenic Escherichia coli (APEC), is a major bacterial disease that affects birds of all ages worldwide, causing significant economic losses. APEC manifests in several clinical forms, including cellulitis, enteritis and several extra-intestinal diseases such as Colibacillosis, Airsacculitis, Omphalitis, Acute septicemia, Salpingitis. This study was carried out to investigate avian pathogenic Escherichia coli in diseased chickens from commercial farms in Sokoto and Kebbi States. A total of 450 cloacal swabs were collected, screened and analyzed using standard culture, isolation biochemical characterization, and molecular techniques. Three hundred and seventy 370 (82.2%) were positive to culture and isolation while one hundred and four 104 (23.1%) were positive to biochemical tests. Following polymerase chain reaction techniques only one hundred and one 101 (22.4%) isolates were confirmed Escherichia coli. Pathotyping of all the confirmed Escherichia coli isolates were carried out to determine the virulence types using the minimum number of virulence-associated genes (VGs) that could identify APEC (iutA, iss, ompT, iroN and hlyF). All isolates were found to be APEC. Among 101 confirmed Escherichia coli isolates, none of the strains contained one virulence gene, no strains contained only two virulence genes, four (4) strains contained three virulence genes, and 30 strains contained four virulence genes. All the five virulence genes iss, ompT, hlyF, and iroN were detected in 67 strains of the confirmed Escherichia coli isolates. Therefore, all the confirmed 101 (100%) Escherichia coli isolates have a minimum of either three (3), four (4), or five (5) VGs (iutA, iss, ompT, iroN and hlyF) which are the minimal predictors of APEC, are therefore confirmed to be all APEC pathotypes. Based on the study findings, avian pathogenic Escherichia coli in diarrhea chickens from commercial farms in the study areas has been established, therefore commercial farms in the study areas should implement stricter biosecurity practices to reduce the spread of E. coli and introducing vaccines specifically designed to target avian pathogenic E. coli (APEC) strains could significantly lower infection rates and reduce reliance on medications.