Abstract
Objectives: To identify the sensitivity of antibiotics against Pseudomonas aeruginosa and Staphylococcus aureus in Chronic suppurative otitis media (CSOM).

Methodology: A total of 100 patients with CSOM were selected for the study at the Department of Otorhinolaryngology, Civil Hospital and Dow Medical College, Karachi, Pakistan from December 2015 to May 2016. Specimens were collected with sterilized cotton swabs and were sent to the central laboratory of Civil Hospital, Karachi for culture and sensitivity. Minimal inhibitory concentration (MIC) was done for Pseudomonas aeruginosa and Staphylococcus auerus.

Results: Monomicrobial growth was present in 95 (95%) samples; five (5%) were sterile. Pseudomonas aeruginosa (38%) and Staphylococcus aureus (28%) were the most common bacterial agents found. Sensitivity pattern of Pseudomonas aeruginosa showed that piperacillin/tazobactem and imipenem was 100% sensitive, followed by ceftazidime, 73%, ciprofloxacin, 63%, amikacin 60%, aztreonam, 59% and gentamicin 50%.
Staphylococcus aureus showed 100% sensitivity to vancomycin followed by amoxicillin/clavulanate, 71.4%; doxycycline, 57%; ciprofloxacin, 50%; clindamycin, 50% and 50% gentamicin, while resistance was found against clarithromycin and erythromycin.

Conclusions: Pseudomonas aeruginosa and Staphylococcus aureus were the most common bacteria isolated from chronic discharging ears. Piperacillin/tazobactem and imipenem were the most sensitive drugs followed by ciprofloxacin and gentamicin.

Key words: Ear infections, otitis media, CSOM.