Antibiotic resistance in coagulase-negative staphylococci isolated from Cope's Gray Treefrog (Hyla chrysoscelis)

Abstract

Two hundred and twenty two Coagulase Negative Staphylococci (CoNS) were isolated from the feces of Cope's gray treefrogs (Hyla chrysoscelis). Seven species were identified with S. sciuri and S. xylosus being the most prevalent. Antibiotic susceptibility of all isolates was determined using the disk diffusion method. Our results indicated 99% of the isolates were resistant to penicillin G and 59% were resistant to oxacillin, a clinical substitute for methicillin. Ten randomly chosen isolates were analyzed for the presence of the mecA gene, which codes for methicillin resistance. The gene was detected in 4 of the 10 isolates. These data suggest the gray treefrog may be harboring inordinate amounts of methicillin resistant CoNS and the mechanism of resistance in some isolates may be mecA independent. The environmental impact of these microbes is unknown, especially due to the recommended use of frogs in elementary and secondary classrooms.