Antibiogram of Enterobacteriaceae isolated from free-range chickens in Abeokuta, Nigeria

Antimicrobial resistance in bacteria from the family Enterobacteriaceae is an important indicator of the emergence of resistant bacterial strains in the community. This study investigated the antimicrobial susceptibility of commensal Enterobacteriaceae from free-range chickens to antimicrobial agents using the broth microdilution. In all, 184 isolates (including 104 Escherichia coli, 44 Klebsiella spp, 20 Salmonella spp. and 16 Enterobacter aerogenes) were resistant to ampicillin (89.7%), chloramphenicol (73.9%), ciprofl oxacin (33.2%), enrofl oxacin (60.3%), neomycin (70.7%), norfl oxacin (45.7%), streptomycin (78.8%) and tetracycline (73.4%). Escherichia coli was resistant to ampicillin (92.3%), chloramphenicol (73.1%), ciprofl oxacin (34.6%), enrofl oxacin (61.5%), neomycin (76.9%), norfl oxacin (46.2%), streptomycin (80.8%) and tetracycline (76.9%). The rate of resistance in Klebsiella spp. was ampicillin (90.9%), chloramphenicol (72.7%), ciprofl oxacin (54.5%), enrofl oxacin (90.9%), neomycin (63.6%), norfl oxacin (63.6%), streptomycin (81.8%) and tetracycline (81.8%). Salmonella spp. showed resistance to ampicillin (80.0%), chloramphenicol (80.0%), enrofl oxacin (20.0%), neomycin (80.0%), norfl oxacin (20.0%), streptomycin (80.0%) and tetracycline (35.0%) but were completely susceptible to ciprofl oxacin. Enterobacter aerogenes was resistant to ampicillin (81.3%), chloramphenicol (75.0%), ciprofl oxacin (6.3%), enrofl oxacin (18.8%), neomycin (37.5%), norfl oxaci