In vitro susceptibility of bacterial keratitis pathogens to ciprofloxacin - Emerging resistance

Objective: To examine in vitro susceptibility of bacterial keratitis pathog ens to ciprofloxacin. Design: Retrospective review. Participants: The authors examined in vitro susceptibility of 1558 corneal isolates from 1303 patients with culture-proven bacterial keratitis seen at the LV Prasad Eye Institute in Hyderabad, India, during the 6-year period between March 1, 1991, and June 30, 1997, Results: Of 1558 corneal isolates, 478 (30.7%) were not sensitive to ciprof loxacin. Among the isolates, 355 (32.5%) of the 1091 gram-positive cocci we re not sensitive to ciprofloxacin, and 2 (10%) of the 20 gram-positive baci lli, 22 (13.3%) of the 165 gram-negative organisms, and 99 (35.1%) of the 2 82 Actinomycetes and related organisms were not sensitive to ciprofloxacin. Results from chi-square for trends analysis showed a trend of significantl y increasing ciprofloxacin insensitivity in bacteria between 1992 and 1997 (P = 0.011). Conclusion: This is the first report of significantly increasing ciprofloxa cin insensitivity among corneal pathogens. Although the lowered cost and co nvenience of dispensing a single, commercially available antibiotic such as ciprofloxacin in the initial treatment of bacterial keratitis is desirable , the emergence of ciprofloxacin resistance is a significant finding in thi s series, and the clinician should proceed with caution in the initial empi ric treatment of bacterial keratitis with ciprofloxacin.