Antibiotics in chronic suppurative otitis media: A bacteriologic study

Objective: This study sought to determine causative microorganisms of chronic suppurative otitis media (CSOM) and to estimate their susceptibility to antibiotic agents. Materials and methods: One hundred sixty-four (164) patients with unilateral or bilateral active chronic suppurative otitis media were prospectively studied. They had chronic ear discharge and had not received any antibiotics for the previous 5. days. Swabs were taken from all patients, and sent to the Microbiology Department for processing. The specimens were cultured and the isolates were identified using standard microbiological techniques. The antibiotic susceptibilities of the isolates were determined with standard antibiotic discs using the Kirby-bauer disc diffusion method. Results: This study analyzes the causal organisms and their sensitivity to various antibiotics. The major organisms isolated were Methicillin sensitive Staphylococcus aureus [MSSA] (45.1%) followed by Pseudomonas aeruginosa (19.5%). The sensitivity of S. aureus (MSSA) was 79.7% to ciprofloxacin, 69% to cotrimoxazole, and 82.5% to gentamicin whereas the sensitivity of P. aeruginosa was 100% to ceftazidime, 84.4% to ciprofloxacin, 90.6% to gentamicin, and 78.1% to Piperacillin. Majority of the isolates of P. aeruginosa were completely resistant to polymixin B (71.9%) whereas 50% of S. aureus (MSSA) showed resistance to Ampicillin. All Methicillin resistant S. aureus (MRSA) isolates showed 100% resistance to Ampicillin, Augmentin and cephalothin. Among the available topical antibiotic preparations for use in the ear, we found gentamicin and ciprofloxacin as the best choices. Conclusion: The study of microbial pattern and their antibiotic sensitivity determines the prevalent bacterial organisms causing CSOM in the local area to start empirical treatment of otitis media and its complications for a successful outcome, and thus to prevent the emergence of resistant strains.