Prevalence and Antibiogram of Generic Extended-Spectrum β-Lactam-Resistant Enterobacteria in Healthy Dogs

This study was conducted to isolate generic extended-spectrum β-lactam-resistant enterobacteria from household dogs in Nigeria, and to determine the antibacterial resistance profile of the isolates. Rectal swabs were collected from 100, randomly selected, apparently healthy household dogs. Isolation of ESBL-resistant enterobacteria was done using Mac Conkey agar supplemented with 4 µg/ml of ceftazidime. Phenotypic characterization of the isolates to generic level was done following standard biochemical methods. Phenotypic resistance of the isolates to antibacterial agents was determined using the disc diffusion method. Out of 27 ESBL-resistant enterobacterial isolates, 40.7% were Escherichia coli, 37% were Klebsiella species, 18.5% were Salmonella species, while 3.7% was Proteus species. Resistance of the E. coli isolates was 81.8% to ampicillin, 27.2% to streptomycin, 54.5% to ciprofloxacin and tetracycline, 45.4% to enrofloxacin, 90.9% to sulphamethoxazole/trimethoprim, 9.1% to amoxicillin/clavulanic acid and 0% resistant to gentamicin. Resistance of the Klebsiella isolates was 80% to ampicillin, 20% to streptomycin and amoxicillin/clavulanic acid, 30% to ciprofloxacin and enrofloxacin, 60% to tetracycline, 90% to sulphamethoxazole/trimethoprim and 10% to gentamicin. Resistance of the Salmonella isolates was 100% to sulphamethoxazole/trimethoprim, 80% to gentamicin and ampicillin, 60% to streptomycin and tetracycline, 20% to amoxicillin/clavulanic acid, and 0% to ciprofloxacin and enrofloxacin. The Proteus isolate was resistant to streptomycin and gentamycin. All the isolates were resistant to ceftazidime and cefotaxime. Resistance of the isolates to more than 3 classes of antibacterial agents tested was 81.8% for E. coli, 70% for Klebsiella and 100% for Salmonella, respectively. This study has shown that household dogs in Nigeria, are colonized by ESBL-resistant Enterobacteriaceae and are potential reservoirs and disseminators of these organisms