Increasing Resistance of Endophthalmitis Isolates To Fluorquinolones– A Sixteen Year Review

Abstract

Abstract: : Purpose: To evaluate the changes in resistance of bacterial endophthalmitis isolates to fluoroquinolones over the past 16 years. Methods: All endophthalmitis culture specimens at the New York Eye and Ear Infirmary microbiology lab collected between January 1, 1987 and December 31, 2002 were restrospectively reviewed. The age, gender, organism, and resistance profiles were recorded and analyzed. Results: Cultures from 1063 consecutive cases of endophthalmitis were reviewed. 54% were female and 46% were male with a mean age of 75 years. Cultures were positive in 57% (606) of which 94% had a single isolate, 5% had 2 isolates, and 1% had 3 isolates. The most common isolates were coagulase negative Staphylococci (42%) and Staphylococcus Aureus (13%). Both organisms demonstrated increasing resistance to ciprofloxacin (introduced for ophthalmic use in 1990) with peaks in resistance in 1994 (32%) and 1997 (48%) for coagulase negative Staphylococci. Comparable peaks in resistance for Staphylococcus Aureus were noted in 1994 (29%), 1997 (42%), and 2000 (67%). Similar resistance patterns were noted to ofloxacin and levofloxacin. Conclusions: The most common endophthalmitis isolates, coagulase negative Staphylococci and Staphylococcus Aureus have demonstrated increasing resistance to fluoroquinolone antibiotics which took on a sinusoidal pattern with progressive increasing peaks of resistance over the course of the study. The importance of this pattern is unknown.

Keywords: endophthalmitis • bacterial disease • pharmacology