Prevalence and antimicrobial susceptibility of staphylococci isolated from the skin surface of clinically normal cats

Samples were collected from 148 adult cats, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, amoxycillin, ampicillin, cephalexin and rifampin. Methicillin resistance was also determined. Ninety-eight isolates were obtained (66% of samples). Coagulase-negative species were most common, and the most frequently isolated species (37 samples) was Staph. felis . Other coagulasenegative species, such as Staph. simulans , Staph. epidermidis and Staph. Saprophyticus were also isolated. Coagulase-positive species were obtained from 40 cats; the most frequent was Staph. intermedius (26 samples), followed by Staph. aureus (14 samples). Resistance to antibiotics was frequently observed, with 58·2% of the isolates showing resistance to at least one drug. Resistance to Penicillin G was observed in 49 of the 98 isolates (50%), 22 samples were resistant to oxacillin (22·4%) and 12 to rifampin (12·2%). Resistance to amoxycillin and ampicillin was very similar to that observed to Penicillin G. Gentamicin was the most active antimicrobial agent. Three MRSA (methicillin-resistant Staphylococcus aureus ) were isolated, which represents 21·4% of the isolates of that species. Nineteen MRS (methicillin resistant staphylococci) were also observed, distributed among Staph. intermedius (eight), Staph. simulans (six) and Staph. felis (five) isolates. The role of these micro-organisms on the skin of cats is discussed.