Multidrug resistance of common bacterial pathogens from wounds and otitis externa in small animals during a 10 year period in Kenya.

Abstract

Antimicrobial resistance is an increasing clinical challenge and a global public health concern. Emergence of resistant pathogens pose a threat to the patient due to the limitations and financial costs in managing them. Bacteriology laboratory records of clinical samples submitted from the University of Nairobi Small Animal Clinic between January 2004 and December 2013 were retrospectively reviewed with the aim to determine prevalence of common bacterial isolates from wound and otitis externa of dogs and cats and their antimicrobial susceptibility profiles The most prevalent bacterial isolates recovered from dogs diagnosed with wounds, surgical site infections and otitis externa were: Staphylococcus aureus constituting 50% (140/280) and Proteus spp. 14% (40/280) respectively. Other less frequently recovered isolates included Pseudomonas spp. constituting 10% (28/280), other Staphylococcus spp. 8.6% (24/280), Streptococcus spp. 7.5% (21/280) and E. coli 5.4% (15/280) respectively. Resistance to antimicrobial agents was observed in the majority of the isolates in the study, with 97% (276/285) of the isolates demonstrating antimicrobial resistance to at least one drug. Antimicrobial resistance to sulphonamides (95%), potentiated sulphonamides (88%), ampicillin (67%), amoxicillin (62%) and tetracycline (56%) was relatively high for all bacterial species examined. Staphylococcus aureus isolates showed 95% resistance to sulfamethoxazole, 55% to ampicillin, 52% to tetracycline and 52% to amoxicillin/clavulanic acid respectively. Pseudomonas spp. showed the highest resistance with all (100%) isolates showing multidrug resistance (MDR) to amoxicillin, amoxicillin/clavulinic acid and sulfamethoxazole. The isolates also showed high level multidrug resistance to cotrimoxazole (93%), ampicillin (93%) and tetracyclines (80%) respectively. Low resistances to gentamicin (9%), norfloxacin (24%) and chloramphenicol (33%) were observed in all bacterial isolates. This study confirms Staphylococcus aureus as the most prevalent bacterial isolate from wounds and otitis externa in small animals. Proteus spp., Pseudomonas spp., Staphylococcus spp., Streptococcus spp. and Escherichia coli in descending order, were also commonly isolated. Gentamicin and norfloxacin, in that order were the most effective antimicrobial agents in the management of wound infections and otitis externa in small animals.