Microbiology and drug sensitivity patterns of chronic suppurative otitis media

To identify the commonest microorganisms associated with chronic discharging ears and their antimicrobial sensitivities.

Descriptive study.

This study was carried out from August 2003 to February 2004 at the Department of Otorhinolaryngology and Head and Neck Surgery, Fauji Foundation Hospital, Rawalpindi.

A total of 124 patients with unilateral or bilateral active chronic suppurative otitis media attending the outpatient clinic were included in the study. All patients were evaluated through detailed history and clinical examination. Pus samples were collected from the discharging ear(s) and sent to the hospital laboratory where culture and sensitivity studies were done for aerobes, anaerobes and fungi and antibiotic sensitivity patterns.

Overall microbiology of 142 samples was studied. Among them, 108 (76%) were pure cultures and 34 (23.9%) were mixed. There were 186 isolates including 182 (97.8%) aerobes, nil anaerobes and only 4 (2.1%) fungi. Pseudomonas aeruginosa 94(50.5%) was the most common isolate, followed by Staphylococcus aureus 44 (23.6%). Drug sensitivities pattern of Pseudomonas aeruginosa showed that ciprofloxacin was active against majority 95.8% of isolates followed by amikacin 83.3%, gentamicin and tobarmycin 60% and cefotaxime 41.6%. Staphylococcus aureus isolates were resistant to penicillin, ampicillin and amoxicillin in 77.2% whereas majority was sensitive to coamoxiclav 81.8% and cephradine 86.3%.

Commonest organisms isolated from chronic discharging ears were Pseudomonas aeruginosa and Staphylococcus aureus. Majority of isolates of Pseudomonas aeruginosa were sensitive to ciprofloxacin. Majority of strains of Staphylococcus aureus were resistant to penicillin. Cephradine and coamoxiclav were effective against most of the isolates of Staphylococcus aureus.