Antibiotic Resistance in <i>Salmonella sp</i> and <i>Escherichia coli</i> Isolated From Poultry in Ibadan, Nigeria

Abstract

Antibiotic therapy is the most important factor that promotes the emergence, selection and spread of antibioticresistant microorganisms in both veterinary and human medicine. In this study, eighty cloacal samples were collected from eight farms in different locations within Ibadan, southwest Nigeria. The cloacal samples were taken for bacterial isolation, characterization and antibiotics susceptibility test. Nutrient agar was used as the growth medium for aerobic organisms, while MacConkey agar (MAC), Desoxycholate citrate agar (DCA), and eosin methylene blue (EMB) agar were used to isolate enterobacteriaceae organisms. From the lactose and non lactose fermenters isolated, 16 Salmonella sp and 45 Escherichia coli isolates were identified by colonial morphology on agars, Gram staining, and biochemical tests. The highest mean total aerobic counts of the organism population isolated were obtained from farms C (6.52±0.17logcfu/ml) and D (6.24±0.10logcfu/ml), while the least counts were from farms G (4.63±0.78logcfu/ml) and H (4.16±0.70logcfu/ml). The highest mean enterobacteriaceae counts were also obtained from farms C and D (4.70±0.56logcfu/ml and 5.79±0.14logcfu/ml) and the least count was from farm H (2.76±0.75 logcfu/ml). Strains of Salmonella sp and E. coli isolated were significantly resistant to gentamicin, erythromycin, chloramphenicol, tetracycline, streptomycin, cefixine and ampicillin. Resistance to gentamicin was the least with 33-71% in Salmonella sp and 25-80% in E. coli. The level of drug resistance in these organisms is ascribed to frequent exposure of the birds to antibiotics which may have generated genomic selective pressure that enabled the organisms to adapt and acquire a resistance.

Keywords: Antibiotic resistance, Salmonella sp, E. coli, poultry, Nigeria.