Multiple antimicrobial resistance of <i>Escherichia coli</i> and <i>Salmonella</i> species isolated from broilers and local chickens retailed along the roadside in Zaria, Nigeria

Abstract

Pathogenic Escherichia coli and Salmonella species are the causative agents of various disease complexes in poultry such as colibacillosis, fowl typhoid, pullorum disease and salmonellosis. Some strains of E. coli and Salmonella spp. have been shown to be resistant to multiple antibiotics. We carried out a bacteriological investigation on 105 cloacal swabs from local and broiler chickens retailed along the roadside in Hanwa, Zaria for the occurrence of E. coli and Salmonella spp. by isolation through culture, and identification using biochemical and serotyping techniques. Serotyping of E. coli isolates was carried out with polyvalent E. coli O157:H7 antisera while Salmonella spp. isolates were serotyped using polyvalent antisera specific for all groups and type-factor for Salmonella spp. Presumptive isolates were subjected to antimicrobial susceptibility testing using 13 panels of antibiotics for both E. coli and Salmonella spp. Results showed that the overall isolation rate of Salmonella spp. was 12 (11.4%), broiler chickens had higher isolation rate 9 (12.0%) of Salmonella than local chickens. However, the isolation rate of E. coli from local chickens 15 (50.0%) was higher compared to broilers 6 (8.0%). Also, non-E. coli O157:H7 and E. coli O157:H7 were isolated from both broilers and local chickens at a frequency of 15 (14.3%) and 6 (5.7%) respectively. The overall isolation rate of E. coli was 21 (20.0%). Multiple antibiotic resistance was observed among local and broiler chickens. However, E. coli and Salmonella species were 100% susceptible to Enrofloxacin. We therefore concluded that E. coli and Salmonella species are prevalent in the cloacae of both broiler and local chickens retailed along the roadside in Hanwa, Zaria, Nigeria and could pose serious veterinary and public health risks.

Keywords: Escherichia coli, Isolation, Salmonella, Serotype, Zaria