Antibiotic Susceptibility Pattern of Causative Organisms of Chronic Supp urative Otitis Media (CSOM) in a District General Hospital in Sri Lanka

Abstract

This study was carried out to determine the aerobic microorganisms involved in chronic suppurative otitis media (CSOM) and their antibiotic susceptibility patterns and to formulate empirical antibiotic guidelines for CSOM patients. Over a period of 1 year, ear swabs from patients with CSOM were submitted to the microbiology laboratory. Patients who had not received antibiotics for the past three days were recruited. All organisms were identified using the standard operating procedures given in the Microbiology Laboratory Manual. Antibiotic sensitivity testing was done using the Stokes disc diffusion method. Ear swabs were taken from 273 patients, of which 257 (94%) yielded positive cultures. Pseudomonas aeruginosa (52%) was the most frequent isolate, followed by methicillin sensitive Staphylococcus aureus (MSSA) (15.7%) and Klebsiellaspp (10.6%). Pseudomonas aeruginosa showed 95% sensitivity to ceftazidime and 74% to ciprofloxacin and gentamicin. MSSA was 100% susceptible to cloxacillinand 95% and 85% to cotrimoxazole and gentamicin respectively, but ciprofloxacin sensitivity was low (35%). We recommend gentamicin as the topical antibiotic of choice for empirical treatment of CSOM while ciprofloxacin and cloxacillin are for systemic therapy. Performing bacterial culture prior to antibiotics is necessary to decide on specific treatment.