ABSTRACT
To evaluate the spectrum of organisms causing endophthalmitis and their resistance pattern to standard antimicrobial agents. Medical records of culture positive eyes treated at Rassoul Akram Hospital for endophthalmitis during the past 5 years were reviewed. Specimens were obtained during pars plana vitrectomy or vitreous tap. Sixty-five isolates including 36 [55.4%] gram-positive organisms, 28 gram-negative organisms [43.1%], and 1 [1.5%] fungus were studied. The most common organism identified was Coagulase-negative staphylococcus in 16 eyes [24.6%]. Among the antibiotics available for intravitreal injection, the least antibiotic resistance was for vancomycin in gram-positive organisms and amikacin and ceftazidime in gram-negative isolates. Gram-positive isolates were the most prevalent organisms; however, a high isolation rate for gram-negative organisms was obtained. Considering that no single antibiotic provides coverage for all of the organisms, a combination therapy using vancomycin/amikacin or vancomycin/ceftazidime seems to be useful as the initial empiric treatment of suspected bacterial endophthalmitis