Journal of Advances in Microbiology

Background: Blindness is and, apparently always has been, a problem in Egypt. Corneal blindness is a major public health problem in which; 1.5–2.0 million new cases of monocular blindness reported annually in developing countries is secondary to corneal ulceration. Bacterial keratitis is one of the most threatening ocular infectious pathologies that can lead to severe visual disability. To help avoiding the specific therapy risks of disease progression and the microbiological investigations being incomplete or misleading, other organisms as virus, fungi, and Acanthamoeba should be considered.

Aims: To isolate and identify different bacterial agents causing keratitis and identify factors associated with bacterial keratitis.

Study Design:  This cross-sectional study was carried out to identify causative pathogens and to determine the demographic characteristics, predisposing factors of keratitis (corneal ulcer).

Place and Duration of Study: Sample: Department of Microbiology, in High Institute of Public Health, and Department of Ophthalmology, Faculty of Medicine, Alexandria University, between; August, 2014 to May, 2015.

Methodology: A total of 100 cases were examined, samples (corneal swab and scrapings) were collected from clinically diagnosed corneal ulcer patients attending Ophthalmology outpatient clinic of Alexandria Main University Hospital. Samples were processed by corneal smear microscopy (potassium hydroxide and Gram stains) and culture examination (5% sheep blood agar, sheep blood chocolate agar, and Sabouraud dextrose agar and brain heart infusion).

Results: Out of 100 cases, 49 (52.1%) cases had bacterial growth, 32 (34%) patients showed fungal growth, 20 (21.3%) cases had viral keratitis and 24 (25.5%) cases had Acanthamoeba corneal infestation. The predominant bacterial isolates were Staphylococcus epidermidis 24 (48%) followed by Pseudomonas species 8 (16%). Aspergillus species 16 (50%) were the most common fungal isolates followed by Fusarium species 10 (31.2%). Common associated factors were diabetes mellitus (29%), and corneal trauma (17%).

Conclusions: Diabetes was the most common general risk factor while corneal trauma was the most common local cause. The main causative organism of microbial keratitis was bacteria, where Staphylococcus spp. the main agent followed by P. aeruginosa. Vancomycin and fluoroquinolones showed higher rates of sensitivities on bacteria compared to other antibacterial agents.