Antibiotic Sensitivity Profiles of Salmonella enterica and some other Non-Lactose Fermenting Bacteria Isolated from Poultry Farms in Ibadan, Oyo State, Nigeria

Abstract

The roles of members of the Gram-negative non-lactose bacilli commonly isolated from animals, apart from the established pathogenic non-lactose bacilli like Salmonella enterica in infections have been variable, though some of them have been associated with various infections in humans. Members of the Gram-negative non-lactose bacilli are sometimes multidrug resistant in nature, thus suggesting the possibility of their involvement in the epidemiology of drug resistance in other pathogenic bacteria. In this investigation, the 29 non-lactose fermenting Gram-negative bacilli isolated by standard methods from a total of 400 cloaca swabs of asymptomatic poultry in Ibadan, identified as – Salmonella enterica 9/29(31.03%); and non-Salmonella enterica non-lactose fermenters (NSNLF) 20/29(68.97%) namely: five Buttiaxella brennerae, two Citrobacter farmeri, three Shigella dysenteriae, five Proteus penneri, three Morganella morganii, one Edwardsiella itulari, and one Yekonella reensburgei, were subjected to antibiotic sensitivity testing using aerobic growth in antibiotic breakpoint concentrations of cefepime, ciprofloxacin, chloramphenicol, tetracycline, ampicillin, kanamycin, nalidixic acid and streptomycin for the Salmonella enterica isolates, while for the other non lactose fermenters; agar-disc diffusion method according to the standard method by the Clinical Laboratory Standard Institute was used. Three of the nine Salmonella enterica, 3/9(33.33%) showed resistance to all the antibiotic tested, while a high level of antibiotic resistance were also observed in the other twenty non - lactose fermenters; three Buttiaxella brennerae; one Morganella morganii; and one Yekonella reensburgei showed resistance to at least ten of the antibiotics tested namely: chloramphenicol, ciprofloxacin, tetracycline, pefloxacin, streptomycin, augumentin, ceftriazone, nitrofurantoin, gentamicin, cotrimoxazole, ofloxacin and amoxicillin. The possible role of these multidrug resistant Gram-negative non lactose fermenting bacilli in the epidemiology of drug resistance among animal pathogens is discussed.

Keywords: Non-Salmonella, Non-lactose Fermenter, Antibiotic sensitivity profile