Anti-microbial resistance of non-clinical E. coli isolates from a commercial layer poultry farm in Imo state, Nigeria

Abstract

The anti-microbial resistance profiles of non-clinical E. coli isolates were studied in an 8 years old commercial layer poultry farm in Imo state, Nigeria currently stocking about 6000 birds of different strains and ages, housed in 4 separate buildings. Isolates were screened against 12 antibiotics using the disc diffusion method. An overall 92% resistance was recorded against tetracycline and was followed by the 76, 72 and 70% recorded against ampicillin, nalidixic acid and cephalexin respectively. Resistance against ciprofloxacin, cotrimoxazole, pefloxacin and gentamycin on the other hand stood at 18, 18, 20 and 20% respectively, while 26% was recorded for oxfloxacin and chloramphenicol indicating these may still be effective in the treatment of E. coli infections in the farm. Across the different poultry pens, E. coli isolates from the Black Nera laying strain of 20 weeks of age (PA) and the Black Nera laying strain of less than one year in lay (PB) recorded 100% resistance to cephalexin, nalidixic acid and tetracycline. Resistance was exclusively high (100%) in isolates from the PB strains, while in those from the PA strain, resistance to streptomycin was also 100%. Isolates from the Bovan Brown laying strain of more than two years in lay (PC) did not show any resistance to oxfloxacin, pefloxacin, gentamycin, cotrimoxazole and chloramphenicol. Resistance rates in isolates from poultry attendants were relatively low with resistance occurring only against five out of the twelve drugs tested. Resistance against tetracycline was the only one above 50%. Dogs living in the farm also harbored isolates having relatively low resistance rates, with only ampicillin resistance reaching up to 100%. Thirty-eight resistance patterns were demonstrated, most of which occurred only once, while the most predominant one (CP-TE), occurred only thrice. Because of the wide variations in drug resistance patterns of the E. coli isolates, it is recommended that antibiotic use in the management of colibacillosis of poultry in the farm should be based on the result of susceptibility tests especially when the inexpensive broad-spectrum readily available first-line antibiotics are being considered.Keywords: anti-microbial resistance, non clinical E.coli, commercial layers, antibiotics, Nigeria International Journal of Natural and Applied Sciences Vol. 1(1) 2005: 68-77