Hospital-base epidemiology,risk factors and microbiological diagnosis of bacterial corneal ulcer / 国际眼科杂志(Guoji Yanke Zazhi)

ABSTRACT

AIM: To determine the predisposing factors, clinical and microbial characteristics of bacterial corneal ulcer.METHODS: Three hundred patients (300 eyes) of clinically suspected microbial corneal ulcer were included in the study. Data was collected through history and slit lamp examination. Using standard techniques, corneal scraping was performed. A portion of each scraping was examined by direct microscopy for the presence of bacteria, fungi and acanthamoeba by using 100g/L potassium hydroxideand also by Gramand staining. Another portion was inoculated directly on the surface of solid media such as blood agar, Mac-Conkey agar, chocolate agar and Sabouraud's agar. A bacterial corneal ulcer was defined as a suppurative corneal infiltrate and overlying epithelial defect associated with presence of bacteria on corneal scraping examination and cured with antibacterial therapy. RESULTS: Of the 300 patients, sixty were lost in follow up, they were excluded from study. Of the remaining 240, bacterial corneal ulcer was identified in 156 (65.0%) patients. The age of patients ranged from 14 to 74 (mean age of 48) years. Majority of them were male (102). Corneal localization of the ulcers was distributed as central in 96 (61.5%) patients and peripheral in 60 (38.5%) patients. Ulcer depth in 82 (52.6%) patients was less than 1/3 of corneal thickness. In 64 (41.0%) patients, anterior chamber inflammation was 1+ to 2+ Tyndall effect with 1+ to 2+ cells present. Bacteria were isolated in 125 (80.0%) patients from the corneal smears. Sixty-nine percent of isolated bacteria were Grams' positive, and 39% were Grams' negative. Gram negative bacteria were associated with severe anterior chamber inflammation (P=0.003) and depth more than 2/3 of cornea (P=0.001). The most frequent organism isolated was Staphylococcus aureus. Forty percent of patients had good visual outcome with visual acuity same or better than the level at admission. Among the others 60% patients, final outcome was poor.CONCLUSION: Bacterial corneal ulcer is aserious ocular infectious disease that remains a therapeutic challenge and vision threatening ocular condition. Rapid isolation of bacteria and treatment with intensive ocular antibiotics represent decisive steps in the management of such pathologies.