In Vitro Susceptibilities of Bacterial Ocular Isolates to... : Cornea (original) (raw)

Laboratory Science

Graves, Adrienne Ph.D.; Henry, Marrieta M.D.; O'Brien, Terrence P. M.D.; Hwang, David G. M.D.; Van Buskirk, Amy; Trousdale, Melvin D. Ph.D.

From Santen (A.G., A.V.B.), Napa, California; Covance Central Laboratory Services (M.H.), Indianapolis, Indiana; the Department of Ophthalmology (T.P.O.), Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland; Cornea Service (D.G.H.), Department of Ophthalmology, University of California, San Francisco, San Francisco, California; Keck School of Medicine of University of Southern California (M.D.T.), Los Angeles California; and Doheny Eye Institute (M.D.T.), Los Angeles, California, U.S.A.

Submitted June 15, 2000.

Revision received November 20, 2000.

Accepted November 22, 2000.

All susceptibility testing was conducted in accordance with the National Committee for Clinical Laboratory Standards (NCCLS).

Address correspondence and reprint requests to Dr. A. Graves, Santen, Inc., 555 Gateway Drive, Napa, CA 94558, U.S.A. E-mail: agraves@ santen-inc.com

Abstract

Purpose.

To evaluate and compare the in vitro antimicrobial activity of levofloxacin versus ciprofloxacin and ofloxacin against ocular isolates from patients with bacterial conjunctivitis.

Methods.

The in vitro antimicrobial susceptibilities of ocular isolates to levofloxacin, ofloxacin, and ciprofloxacin were determined using both the agar disk diffusion and broth dilution methods.

Results.

Disk diffusion susceptibility testing disclosed that 99% (100 of 101 isolates) of Gram-negative isolates and 98% (127 of 129 isolates) of Gram-positive isolates were susceptible to levofloxacin; 96% (97 of 101 isolates) of Gram-negative isolates and 78% (100 of 129 isolates) of Gram-positive isolates were susceptible to ofloxacin; and 94% (95 of 101 isolates) of Gram-negative isolates and 61% (79 of 129 isolates) of Gram-positive isolates were susceptible to ciprofloxacin. Broth dilution testing disclosed that 99% (72 of 73 isolates) of Gram-negative isolates and 98% (111 of 113 isolates) of Gram-positive isolates were susceptible to levofloxacin; 96% (70 of 73 isolates) of Gram-negative isolates and 92% (104 of 113 isolates) of Gram-positive isolates were susceptible to ofloxacin; and 95% (69 of 73 isolates) of Gram-negative isolates and 82% (93 of 113 isolates) of Gram-positive isolates were susceptible to ciprofloxacin.

Conclusions.

In this study, levofloxacin demonstrated superior in vitro activity against human bacterial conjunctival isolates compared with either ofloxacin or ciprofloxacin (levofloxacin > ofloxacin > ciprofloxacin).