Bacterial profile and antimicrobial susceptibility patterns from external ocular infections and associated risk factors at the All Africa Leprosy Rehabilitation and Training Center (ALERT), Addis Ababa, Ethiopia

Background: Bacteria are major causative agents that frequently cause infections of the eyes and loss of vision. Resistance of bacteria isolated from ocular infections to antimicrobial agents is a global concern. Objective: The aim of this study was to determine the prevalence of different bacterial isolates and their antimicrobial susceptibility pattern in patients with external ocular infections and to determine any associated risk factors. Methods: A cross sectional study was conducted from May to August 2015 in ALERT outpatient and inpatient department of Eye Clinic. A total of 288 samples were collected which were processed for bacterial culture according to standard procedures. Presumptive isolates were further identified by a series of biochemical tests. The antimicrobial susceptibility patterns of the isolates were determined by the disk diffusion method. The data were entered and analyzed using SPSS software version 20. Results: A total of 288 patients were enrolled. The overall prevalence of bacterial pathogens among external ocular samples was 171/288 (59.4%). Gram-positive bacteria were the most common isolates accounting for 70.2% (120/171). Staphylococcus aureus was present in 36.8% of the cases (63/171). Most (91.6%) of the bacteria isolated showed high resistance to Penicillin (120/131) and Tetracycline (70.4%; 119/169). Gentamicin was the most effective antibiotic against gram-positive and gram-negative bacteria (94%, 161/171). The overall prevalence of multiple drug resistance was 159/171 (93%): gram-positive 117/120 (97.5%) and gram-negative 42/51 (82%). Most variables did not have a statistically significant association with presence of ocular infection; only repeated infections were observed to have significant association. Conclusion: The prevalence of bacterial pathogens among external ocular samples was high. Most of the isolates were drug resistant to commonly used antibiotics. Gentamicin and Ciprofloxacin were the most effective antimicrobial agents for both gram-positive and gram-negative bacteria.