Bacteriology and Risk Factors of Bacterial Keratitis in Jimma, Southwest Ethiopia.

BACKGROUND In East Africa, particularly in Ethiopia, bacterial keratitis is a major cause of blindness. OBJECTIVE The aims of this study were to identify risk factors of bacterial keratitis and the spectrum of bacterial etiologies, and to assess the in-vitro antimicrobial susceptibility of these bacterial isolates at Jimma University Specialized Hospital, Southwest Ethiopia. METHODS A prospective study was employed from January 2012 to June 2012 from which a total of 24 patients with bacterial keratitis were included in the study. Corneal scrapings were collected, transported and microbiologically processed using standard operating procedures. RESULTS Four different predisposing factors for bacterial keratitis were identified: corneal trauma 9 (37.5%), blepharitis 7 (29.2%), herpetic keratitis, and use of contaminated medications 4. Bilateral corneal infection was found in 5 (20.8%) of the cases. A total of 24 corneal scrapings were collected for microbiological evaluation, of which 20 (83%) had bacterial growth. The isolated bacterial pathogens were Pseudomonas aeruginosa 10 (41.7%), Staphyloccus aureus 5 (20.8%), Serratia marcescens 3 (12.5%), followed by Streptococcus pneumoniae 2 (8.3%). Antimicrobial susceptibility testing revealed that 85% of Gram-negative bacilli were susceptible to gentamicin and ciprofloxacin, while 86% of Gram-positive cocci were susceptible to vancomycin and Ciprofloxacin. CONCLUSIONS Corneal trauma was the most common risk factor for bacterial keratitis followed by blepharitis. Bacteriological analysis of corneal scrapings also revealed that P. aeruginosa was the most common isolate followed by S. aureus; the antibiotic with the highest susceptibility was ciprofloxacin. As drug resistance among bacterial pathogens is an evolving process, routine surveillance and monitoring studies should be conducted to provide an update and most effective empirical treatment for bacterial keratitis.