One-day application of topical moxifloxacin 0.5% to select for fluoroquinolone-resistant coagulase-negative Staphylococcus.
OBJECTIVE
To compare selection for fluoroquinolone-resistant bacteria between 1-day and 3-day application of topical moxifloxacin 0.5%.


METHODS
Department of Ophthalmology, Stanford University, Stanford, California, USA.


METHODS
After investigative review board approval, patients scheduled for ocular surgery were randomized to receive topical moxifloxacin 0.5% drops 4 times a day for 1 day or 3 days preoperatively. Conjunctival cultures were obtained at baseline and after antibiotic application. Bacteria were identified and tested for resistance to a battery of antibiotic agents using the Kirby-Bauer disk-diffusion method. The differences in resistance distributions for the most commonly isolated bacteria between baseline (T0) and after antibiotic administration (T1) were compared between the 2 treatment groups.


RESULTS
Coagulase-negative Staphylococcus (CNS) were the most common bacteria isolated at T0 and T1. At T0, the proportion of CNS isolated in the 1-day group (n = 63) that was resistant to fluoroquinolones ranged from 4% to 22% depending on the antibiotic agent tested. After 1-day treatment with moxifloxacin, the percentage of resistant bacteria increased significantly (range 13% to 67%) for all fluoroquinolones except gatifloxacin (P<.05). Resistance to gentamicin and tobramycin also increased significantly. However, patients treated for 3 days (n = 57) showed no differences in bacterial resistance rates to any antibiotic agent tested.


CONCLUSIONS
Prophylactic topical moxifloxacin 0.5% treatment starting 1 day before ocular surgery resulted in a significant increase in fluoroquinolone-resistant bacteria, while a 3-day antibiotic regimen did not select for resistant organisms.
Department of Ophthalmology, School of Medicine, Stanford University, Stanford, California 94304, USA.
Lingmin
L
He
Christopher N
CN
Ta
Herminia
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Miño de Kaspar
D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis; D001372:Aza Compounds / Q000008:administration & dosage / Q000627:therapeutic use*; D003228:Conjunctiva / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D000077266:Moxifloxacin; D013508:Ophthalmologic Surgical Procedures; D011804:Quinolines / Q000008:administration & dosage / Q000627:therapeutic use*; D012307:Risk Factors; D013210:Staphylococcus / Q000302:isolation & purification*
D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D000077266:Moxifloxacin