Abstract
Objective: To assess the bacteriological profile of acute otitis externa in adults.
Methodology: This cross-sectional study was conducted at Ear, nose, and throat (ENT) department of Sindh Government Qatar Hospital Karachi, from 1st March 2024 to 31st December 2024. All cases of acute otitis externa (aged 18-50 years) were enrolled. A detailed medical history followed by comprehensive ENT examination was done for all patients. Aural swabs were sent for microbiological assessment. Statistical analysis was performed using SPSS version 23. A p-value of <0.05 was calculated using Chi square test.
Results: A total 139 participants were included, with a mean age of 32.5±7.3 years and 53.2% were females. The presenting symptoms were ear pain (86.33%) and ear blockage (79.1%). Pseudomonas aeruginosa (49.6%) and Staphylococcus aureus (30.93%) were the commonly isolated microbes. Ciprofloxacin showed 70% sensitivity for Pseudomonas aeruginosa, and 100% Staphylococcus aureus were sensitive to Vancomycin. A significant relationship was observed between prior antibiotic use and increased bacterial resistance (p=0.002).
Conclusion: Pseudomonas aeruginosa and Staphylococcus aureus were the most common pathogens isolated in acute otitis externa in adults. The efficacy of ciprofloxacin may have potential benefit of topical treatments in reducing systemic antibiotic use. Continual surveillance and public awareness programs are essential to combat antimicrobial resistance.

Key words: Ciprofloxacin, Pseudomonas aeruginosa, otitis externa, Staphylococcus aureus.