Abstract
Purpose: :
To report the spectrum, frequency and sensitivities of anaerobic bacteria causing endophthalmitis over the last 20 years.
Methods: :
From the Microbiology Laboratory Department records, all anaerobic bacterial vitreous isolates were reviewed between January 1, 1991 and September 30, 2011. All the vitreous isolates were tested for vancomycin, ceftazidime, gatifloxacin and moxifloxacin sensitivities at high and low dose.
Results: :
Anaerobic bacteria accounted for 115 of 1386 (8.3%) in vitreous culture-positive isolates from 1991 to 2011. The most common bacteria for the isolates was Propionibacterium acnes (89.4%). Other etiologies included, Bacteroides species (5.3%), Peptostreptococcus species (2.6%), Propionibacterium granulosum (0.9%), Propionibacterium avidum (0.9%), and Clostridum subterminale (0.9%). The sensitivities were as follows: 92% of the isolates were sensitive to vancomycin (222 µg/ml & 22 µg/ml), 66.7% were sensitive to high dose ceftazidime (5 µg/ml) and 33.3% were sensitives to low dose ceftazidime (0.5 µg/ml). The sensitivities to fluoroquinolones, was as follows: 41.7% of the isolates were sensitive to high dose moxifloxacin (1.1 mg/ml), 25% were sensitive to low dose moxifloxacin (0.11 mg/ml), 50% of the isolates were sensitive to high dose gatifloxacin (0.67 mg/ml), and 8.3% were sensitive to low dose gatifloxacin (0.07 mg/ml).
Conclusions: :
In the current study, anaerobic bacteria account for less than 10% of culture positive vitreous isolates. The most common etiology was Propionibacterium acnes. Regarding the sensitivities, vancomycin was the most effective antibiotic against anaerobes pathogens. The fluoroquinolones had a variable effect in the high dose group, but were not generally effective in the low dose group.
Keywords: endophthalmitis • vitreous