Potential bacterial pathogens of external ocular infections and their antibiotic susceptibility pattern at Hawassa University Teaching and Referral Hospital, Southern Ethiopia

Bacterial external ocular infection is a common health problem along with increase and spread of drug resistance in Ethiopia. The objective of this study was to identify potential bacterial isolate of external ocular infections and their antimicrobial susceptibility patterns in patients attending eye clinic of the Hawassa University Teaching and Referral Hospital, from December 2012 to April 2013. A total of 281 consecutive, non-repetitive ocular specimens were collected among conjunctivitis cases (n=140), blepharitis cases (n=55), keratitis cases (n=31), dacryocystitis cases (n=19), and other cases (n=36). All samples were processed for culture and identification by standard methods. Susceptibility testing was done by Kirby-Bauer method as per Clinical and Laboratory Standards Institute (CLSI) guideline. Out of 281 ocular specimens submitted to culture, 137 (48.8%) specimen were positive. The most common bacterial isolates were Gram positive cocci (n=88; 61.5%). The predominant bacterial species isolated was Staphylococcus aureus (n=30; 21.0%) followed by coagulase negative Staphylococci (CoNS) (n=26; 18.2%) and Streptococcus pneumoniae (n=20; 14.0%). In vitro ciprofloxacin was effective against 86% of isolated pathogen. Multi-drug resistance was observed in 69.9% of the bacterial isolates. Our study confirmed that S. aureus was the overall predominant isolated pathogen followed by CoNS, S. pneumoniae and Klebsiella spp. Gram positive isolates were more susceptible to amoxicillin-clavulanic acid and vancomycin, whereas Gram negative isolates were more susceptible to ciprofloxacin and gentamicin. Relatively, ciprofloxacin is effective against most isolated pathogen.