DISTRIBUTION OF ANTIBIOTIC-RESISTANT Enterococcus species AND Escherichia coli RECOVERED FROM SOME POULTRY FARMS IN EDO STATE, NIGERIA

Abstract

Enterococci and Escherichia coli serve as key indicator bacteria for several veterinary and human resistance surveillance systems. E. coli and Enterococcus species have been implicated in extra-intestinal and intestinal infections, gastrointestinal infections, urinary tract infections, meningitis, septicaemia, and peritonitis. The present study was carried out to determine the antibiotic resistant profiles of E. coli and Enterococcus species from poultry farms in Benin City, Nigeria.

A total of 73 samples were collected from five different poultry farms in Benin City between May and October 2017. Standard culture-based methods were adopted in the isolation and identification of Enterococcus species. Analytical profile index was used to identify the Enterococcus species. Antibiotic susceptibility profiles of the isolates were carried out using Kirby-Bauer disc diffusion method.

The range of population cell density of Escherichia coliand Enterococcus species from the farms are as follows [Drinker: E. coli 0.06 - 3.96 Log₁₀ cfu/mL, Enterococcus species 1.08 - 3.79 Log₁₀ cfu/mL; Tank: E. coli no cell growth - 0.06 Log₁₀ cfu/mL, Enterococcus species no cell growth - 1.86 Log₁₀ cfu/mL; Borehole: E. coli no cell growth, Enterococcus species no cell growth - 1.15 Log₁₀ cfu/mL]. The range of prevalence of E. coli and Enterococcus species based on proliferation on selective cultivation medium are as follows [Drinker: E. coli 16.3 - 100%, Enterococcus species 100%; Tank: E. coli 0 - 33%, Enterococcus species 0 - 100%; Borehole:E. coli 0%, Enterococcus species 0 - 16.3%]. Antibiotic resistance profile of Enterococcus species were as follows: erythromycin 19(66%), penicillin G 16(55%), piperacillin 14(48%), clindamycin 25(86%), vancomycin 13(45%), chloramphenicol 21(72%), and tetracycline 13(45%). Antibiotic susceptibility profiles of E. coli isolates revealed different resistant profiles such as piperacillin 16(76%), ceftazidime 13(62%), aztreonam 17(81%), and tetracycline 14(67%). A total of 2(20%) E. faecalis were resistant to 11 antibiotics (CIP^R-NOR^R-TET^R-IMI^R-CHL^R-KAN^R-VAN^R-CLI^R-PTZ^R-PEN^R-ERY^R) which belongs to 9 antimicrobial classes with a multiple antibiotic resistant index of 0.8. For E. coli, a total of 2(9.5%) were resistant to 13 antibiotics (PTZ^R-CTX^R-CRO^R-CXM^R-CAZ^R-ATM^R-ETP^R-IMI^R-MEM^R-GEN^R-KAN^R-TET^R-CIP^R) which belongs to 7 antimicrobial classes with a multiple antibiotic resistant index of 0.9. The biofilm formation profile of E. coli revealed that 3(14.3%) were non biofilm formers, 2(9.5%) were for weak biofilm formers, 7(33.3%) were for moderate biofilm formers and 9(42.9%) were for strong biofilm formers. Biofilm formation for E. faecalis is as follows[non biofilm formers 0(0%), weak biofilm formers 2(20%), moderate biofilm formers 3(30%), strong biofilm formers 5(50%)]; E. faecium [non biofilm formers 0(0%), weak biofilm formers 0(0%), moderate biofilm formers 3(42.9%), strong biofilm formers 4(57.1%)]. The occurrence of E. coli and enterococcal strains exhibiting antimicrobial resistance traits with virulence potential that represent potential threats to the health of poultry birds and associated humans, highlights the need for additional monitoring studies to elucidate the bacterial population structure and the dynamics of transmission of these microorganisms among animals, humans and the environment.