Isolates and antibiotic sensitivity of eighty culture-proven endophthalmitis cases from Istanbul

To investigate the spectrum of organisms causing endophthalmitis and their sensitivity to commonly used antimicrobial agents.

Medical records of 80 consecutive patients treated at Beyoglu Eye Hospital for endophthalmitis from January 2001 to April 2006 were reviewed. Specimens were obtained from either the vitreous (93%, 81/87) or anterior chamber (7%, 6/87) during pars plana vitrectomy or vitreous tap, and were inoculated into blood culture bottles. A Kirby-Bauer disk diffusion test was performed to determine antibiotic susceptibility. The outcome measures included isolates identified and antibiotic sensitivity of the specimens.

Fifty-six of 87 (64.4%) isolates were Gram-positive organisms, 29 (33.3%) were Gram-negative organisms, and 2 (2.3%) were fungi. The most common organism group identified was coagulase-negative staphylococci in 26.4% (23/87). While vancomycin was active against all Gram-positive isolates tested (100%), ceftazidime had the highest susceptibility rate (100%) for Gram-negative organisms isolated.

Although coagulase-negative micrococci predominated in this series, a high isolation rate for Gram-negative organisms was obtained. High susceptibility rates for ofloxacin make it an alternative to ceftazidime and vancomycin in both Gram-negative- and Gram-positive-derived endophthalmitis, respectively. Studies with larger series and additional antibiotics are needed to confirm these findings.