Epidemiology, Genetic Diversities and Antibiotic Resistance in Isolates of <em>E</em>. <em>coli</em>, ESBL- <em>E</em>. <em>coli</em> and <em>Salmonella </em>Species from Commercial Poultry Farms in Ibadan, Oyo State, Nigeria

Escherichia coli (E. coli) and Salmonella spp are bacteria commonly found in the intestinal flora of humans, other mammals, animals, and birds. These two pathogens are the most important food-borne pathogens of public health importance in poultry globally. This study was designed to determine the antibiotics resistance patterns, identify resistance genes and ESBL production in E. coli and Salmonella species isolated from commercial poultry farms across Nigeria. A subset of 101 isolates (24 putative Salmonella and 77 putative E. coli) from a collection obtained at poultry farms in Nigeria , were analysed in this study. Of the 24 confirmed Salmonella, 7 isolates were fully susceptible and had no resistance genes, these were the two Dugbe&rsquo;s and five Isangi serovars. The antimicrobial class with the highest prevalence of resistance was the quinolones with 71% of isolates having resistance to Ciprofloxacin and Nalidixic Acid. None of the Salmonella isolates had resistance to Amikacin, Azithromycin, Cephalosporins (2nd &ndash; 4th generation), Colistin, Meropenem, Tigecycline and Trimethoprim. There was a much higher resistance frequency in the E. coli compared to the Salmonella. Over 80% of isolates have resistance to Fluoroquinolones (Ciprofloxacin and Nalidixic Acid) with a similar percentage having resistance to tetracyclines. No isolates had an AmpC phenotype. The MIC distribution for the E. coli is also far greater than the Salmonella with a higher prevalence of MDR strains. Notable genes identified in isolates include: sul2, aph(3'')-Ib, aph(6)-Id, blaCTX-M, blaOXA, blaCTX-M-15, CTX-M-15, CTX-M-27, CTX-M-65 and the most prevalent been CTX-M-55. The study revealed that Salmonella and E. coli from in Oyo State are becoming more resistant to antibiotics.