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

To examine in vitro susceptibility of bacterial keratitis pathogens to ciprofloxacin.

Retrospective review.

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.

Of 1558 corneal isolates, 478 (30.7%) were not sensitive to ciprofloxacin. Among the isolates, 355 (32.5%) of the 1091 gram-positive cocci were not sensitive to ciprofloxacin, and 2 (10%) of the 20 gram-positive bacilli, 22 (13.3%) of the 165 gram-negative organisms, and 99 (35.1%) of the 282 Actinomycetes and related organisms were not sensitive to ciprofloxacin. Results from chi-square for trends analysis showed a trend of significantly increasing ciprofloxacin insensitivity in bacteria between 1992 and 1997 (P = 0.011).

This is the first report of significantly increasing ciprofloxacin insensitivity among corneal pathogens. Although the lowered cost and convenience 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 this series, and the clinician should proceed with caution in the initial empiric treatment of bacterial keratitis with ciprofloxacin.