Clinical, microbiological, and molecular characterization of methicillin-resistant Staphylococcus aureus infections of cats.
OBJECTIVE
To compare clinical information obtained from medical records of cats with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S aureus (MSSA) infections, evaluate antibiograms of MRSA and MSSA for multiple-drug resistance (MDR), and characterize the strain type and staphylococcal chromosome cassette (SCC)mec type of each MRSA.


METHODS
70 S aureus isolates obtained from 46 cats.


METHODS
Clinical information obtained from medical records, including signalment, clinical signs, histologic examination of affected tissues, and outcomes, was compared between the 2 groups. Composite antibiograms of MRSA and MSSA were compared statistically. The MRSA strains were characterized by use of pulsed-field gel electrophoresis and SCCmec typing.


RESULTS
No statistical differences in signalment or subjective differences in clinical signs or outcomes were detected between groups with MRSA or MSSA infection. Significant differences in antimicrobial resistance were detected, with MRSA having complete resistance to fluoroquinolone and macrolide antimicrobials, whereas MSSA maintained a high frequency of susceptibility. Seven pulsed-field patterns were observed in 15 MRSA strains; all but 1 were highly related. All MRSA isolates contained a type II SCCmec element.


CONCLUSIONS
Because MDR cannot be predicted in staphylococcal infections in cats on the basis of clinical signalment, culture and susceptibility testing are recommended whenever initial empirical treatment is unsuccessful. Molecular characterization of MRSA strains suggests that there has been reverse-zoonotic transmission from humans.


CONCLUSIONS
The SCCmec type II element is typically associated with nosocomial MRSA infections of people. Cats may serve as reservoirs for MRSA infections in humans.
Morris
Daniel O
DO
Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, 19104, USA.
Mauldin
Elizabeth A
EA
O'Shea
Kathleen
K
Shofer
Frances S
FS
Rankin
Shelley C
SC
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002371:Cat Diseases / Q000382:microbiology*; D002415:Cats; D005260:Female; D008297:Male; D016106:Methicillin Resistance; D010802:Phylogeny; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics
D000900:Anti-Bacterial Agents