Methicillin resistance among staphylococci isolated from dogs.
OBJECTIVE
To determine whether methicillin-resistant staphylococci from dogs expressed the mecA gene and to determine what proportion of canine staphylococcal isolates positive for the mecA gene were resistant to oxacillin and other antibiotics.


METHODS
25 methicillin-resistant (10 coagulase-positive and 15 coagulase-negative) and 15 methicillin-susceptible (8 coagulase-positive and 7 coagulase-negative) staphylococci isolated from dogs.


METHODS
All strains were tested for methicillin resistance by use of oxacillin agar screening and identified by use of standard techniques. Minimum inhibitory concentrations of 16 antibiotics were determined for all 40 isolates. A polymerase chain reaction method targeting a 533-basepair fragment of the mecA gene was used to detect mecA gene expression.


RESULTS
23 of the 25 methicillin-resistant isolates and none of the methicillin-susceptible isolates possessed the mecA gene. For 10 of 16 antibiotics, the proportion of mecA-positive isolates that were resistant or of intermediate susceptibility was significantly higher than the proportion of mecA-negative isolates that were resistant or of intermediate susceptibility. Only 1 methicillin-resistant coagulase-positive isolate was identified as Staphylococcus intermedius; the other 9 were identified as S. aureus.


CONCLUSIONS
Results confirm that staphylococci isolated from dogs may have methicillin resistance mediated by the mecA gene. Isolates positive for the mecA gene were more likely to be resistant to various antibiotics than were isolates negative for the mecA gene. Results suggest that in dogs, infections caused by staphylococci that have the mecA gene may be difficult to treat because of resistance to antibiotics.
Gortel
K
K
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA.
Campbell
K L
KL
Kakoma
I
I
Whittem
T
T
Schaeffer
D J
DJ
Weisiger
R M
RM
D000668:Ampicillin Resistance; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D003030:Coagulase / Q000378:metabolism; D004285:Dogs / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D006602:Hexosyltransferases; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics; D010068:Oxacillin / Q000494:pharmacology; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000494:pharmacology; D010458:Peptidyl Transferases; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013210:Staphylococcus / Q000187:drug effects* / Q000235:genetics*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D003030:Coagulase; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010068:Oxacillin