ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF BACTERIAL AND FUNGAL OCULAR ISOLATES FROM TERTIARY CARE OPHTHALMIC HOSPITALS IN CHENNAI

BACKGROUND Infectious keratitis is an ophthalmic emergency that needs immediate institution of treatment. Recent studies have shown increasing evidence of resistance of microbes to antimicrobial agents, which have further added to the reasons for poor prognosis in microbial keratitis. Aims and Objectives- This study was carried out to understand the antimicrobial susceptibility pattern of bacterial and fungal isolates in keratitis. MATERIALS AND METHODS A total of 150 corneal scraping samples were collected and identified by standard protocol and were tested for antibiotic susceptibility as per CLSI guidelines with various groups of antibiotics. MIC for vancomycin, amphotericin B and itraconazole were determined for study isolates by agar dilution method. RESULTS Out of 150 corneal scraping samples, 97 (64.6%) showed culture positivity. Among bacterial, fungal and parasitic agents isolated fungi were the predominant aetiological agents. Staphylococcus aureus (26.4 %), Aspergillus sp. and (24.8 %) Acanthamoeba sp. were the most frequently isolated bacterial, fungal and protozoan aetiological agents respectively. Majority of the bacterial isolates were susceptible to amikacin (94.1%) and were least susceptible to cotrimoxazole (26.4%). All Staphylococcus sp. were found to be susceptible to vancomycin with MIC range of 0.25 - 0.5 mu g/mL. More than 50% of fungal isolates were susceptible to both amphotericin B and itraconazole and none of the fungal isolates were susceptible to fluconazole. About 85.9% of fungal isolates had MIC value of (MIC < 2 mu g/mL) for itraconazole. CONCLUSION This study suggests that the in vitro susceptibility testing of bacterial and fungal isolates of infectious keratitis is extremely useful in clinical management and should be performed as a routine diagnostic protocol.