In vitro activity of fluoroquinolones, vancomycin, and gentamicin against methicillin-resistant Staphylococcus aureus ocular isolates.
OBJECTIVE
To determine the antibacterial activity of fluoroquinolones, vancomycin, and gentamicin against methicillin-resistant Staphylococcus aureus (MRSA) ocular surface isolates.


METHODS
Retrospective review.


METHODS
MRSA isolates were obtained from 21 patients. The MIC(50) (mean inhibitory concentration)(microg/ml) values of 31 MRSA ocular surface isolates were determined for gatifloxacin, moxifloxacin, ciprofloxacin, ofloxacin, vancomycin, and gentamicin using the Etest (AB Biodisk, Solna, Sweden) or the VITEK system (bioMérieux, Inc, Durham, North Carolina, USA). Susceptibility data were interpreted based on criteria specified by the Clinical and Laboratory Standards Institute (CLSI).


METHODS
MIC(50) values in microg/ml and interpretation of susceptibility or resistance.


RESULTS
In vitro resistance rates and median MIC(50) in microg/ml for the MRSA isolates were: gatifloxacin (71%, 8.0), moxifloxacin (68%, 8.0), ciprofloxacin (94%, 8.0), ofloxacin (94%, 8.0), vancomycin (0%, 1.0), and gentamicin (3%, 0.5).


CONCLUSIONS
MRSA ocular isolates exhibited a relatively high rate of in vitro resistance to all fluoroquinolones tested, including the fourth generation. In contrast, MRSA isolates were found to be highly sensitive to vancomycin and gentamicin.
Kotlus
Brett S
BS
Long Island Jewish Medical Center, Albert Einstein College of Medicine, New Hyde Park, New York, USA. Kotlus@gmail.com
Wymbs
Richard A
RA
Vellozzi
Ernestine M
EM
Udell
Ira J
IJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024841:Fluoroquinolones / Q000494:pharmacology*; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D008712:Methicillin / Q000494:pharmacology; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D014640:Vancomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D005839:Gentamicins; D014640:Vancomycin; D008712:Methicillin