Characterization of antibiotic resistance and species diversity of staphylococci isolated from apparently healthy farm animals

Abstract

Background: Staphylococcus species are adaptable commensals usually involved in a diverse multiplicity of ailments in animals and humans. This study surveyed the occurrence, antibiotic-resistance profile and putative resistant genetic elements of staphylococci isolates from apparently healthy farm animals

Methodology: Nasal and rectal samples were collected from a total of 400 cows and pigs in Benin City between May and December 2017. Staphylococci were isolated following aerobic cultures of samples using standard microbiological methods. Susceptibility profiles of the isolates to eighteen selected antimicrobials were determined using the Kirby-Bauer disk diffusion test. Species of staphylococci were established and antibiotic resistance genes detected by the polymerase chain reaction using species-specific and antibiotic-resistant primers respectively

Result: A total of 139 staphylococci isolates were phenotypically and genotypically identified from the food-producing animals; 87 (62.6%) from pigs and 52 (37.4%) from cows. The most frequent Staphylococcus species were Staphylococcus haemolyticus 38 (27.3%), Staphylococcus aureus 27 (19.4%) and Staphylococcus capitis 21 (15.1%). Antibiotic resistance profile showed 120 (86.3%) isolates to be resistant to penicillin G, 100 (71.9%) to nalidixic acid and 99 (71.2%) to minocycline. The prevalence of antibiotic resistance genes assessed were mecA 78 (56.1%), mphC 23 (16.6%), and ermA 20 (14.4%).

Conclusion: Our finding indicates that food animals are potential reservoirs of antibiotic resistant staphylococci which pose a significant threat to food security and public health.

Keywords: food animals; antibiotic-resistant; foodborne pathogen; staphylococci; resistance elements