MICROBIOLOGY OF CHRONIC SUPPURATIVE OTITIS MEDIA - EXPERIENCE AT BAHAWALPUR

Microbiology of Chronic Suppurative Otitis Media

Abstract

Objective: To determine the aerobic microorganisms involved and their antibiotic sensitivity pattern in patients with chronic suppurative otitis media (CSOM) to provide a guideline for making a protocol for empirical antibiotic therapy.
Design: Descriptive study.
Place and Duration of study:  The study was conducted from Sept 2005 to April 2007 at the department of ENT and Microbiology, Combined Military hospital Bahawalpur. 
Patients and Methods:  A total of 178 patients with unilateral or bilateral active chronic suppurative otitis media attending the outpatient clinic were included in the study. All the patients were evaluated through detailed clinical history and clinical examination. Pus samples were collected from the discharging ear(s) and sent to microbiology section of hospital laboratory where aerobic cultures were done. Antibiotic sensitivity testing was done with standard antibiotic discs using Kirby-Bauer disk diffusion method as per National Committee for Clinical Laboratory Standards recommendations.
Results: From the clinical specimens of 178 patients enrolled in the study, microbiological culture was yielded from 130 (73%) specimens. There were 116, (89%) bacterial isolates and 14, (11%) fungi. Pseudomonas aeruginosa 58 (45%) was the most common isolate, followed by Staphylococcus aureus 52 (40%) including two isolates of Methicilliresistent Staphylococcus Aureus (MRSA). Antibiotic sensitivities of Pseudomonas aeruginosa showed that 100% isolates were sensitive to Piperacillin/Tazobactam, where as 86% isolates were sensitive to ceftazidime and 83% to ciprofloxacin. Only 45% of Pseudomonas aeruginosa isolates were sensitive to gentamicin and 48% to amikacin. For Staphylococcus aureus (other than MRSA), 100% isolates were sensitive to cloxacillin, 80% to ciprofloxacin and 68% to gentamicin. Only 60% isolates were sensitive to chloramphenicol and 32% to cotrimoxazole.
Conclusion: Pseudomonas aeruginosa was the most common isolate followed by Staphylococcus aureus. More than 80% of the two organisms were sensitive to quinolones. It is therefore concluded that the topical preparation of quinolones should be included in the formulary to cover the most common aerobic isolates involved in CSOM.