Bacterial Pathogens and Antimicrobial Susceptibility Mapping in Patients with Chronic Suppurative Otitis Media

International Journal of Medicine and Medical Sciences | Vol. 15, No. 5, May 2025 | pp. 33–40

DOI: 10.46882/2025/IJMMS/150033

Original Research Article

Bacterial Pathogens and Antimicrobial Susceptibility Mapping in Patients with Chronic Suppurative Otitis Media

Elizabeth A. Cole¹, Moses Z. Tarawallie², Victoria N. Okoye¹*

¹Department of Medical Microbiology, College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown, Sierra Leone.

²Department of Otorhinolaryngology, Connaught Hospital, Freetown, Sierra Leone.

Abstract:

Chronic suppurative otitis media (CSOM) is a major cause of preventable hearing loss in developing areas, with treatment increasingly complicated by the emergence of multidrug-resistant pathogens. This prospective cross-sectional study identified the predominant bacterial pathogens and mapped their antimicrobial susceptibility profiles among patients presenting with symptomatic CSOM. Ear swabs collected from 200 patients presenting with persistent purulent ear discharge for > 12 weeks were cultured. Bacterial confirmation was achieved using standard automated methods, and susceptibility profiles were assessed using the disk diffusion technique. Significant bacterial growth was confirmed in 84.5% (169/200) of the participants. Pseudomonas aeruginosa was the most common isolate (38.5%), followed by Staphylococcus aureus (28.4%), Proteus mirabilis (14.2%), and Klebsiella pneumoniae (10.1%). Antibiogram mapping revealed high resistance rates among Gram-negative isolates to amoxicillin-clavulanic acid (84.4%) and cefuroxime (76.6%). Resistance to ciprofloxacin—the standard agent in topical ear drops—was detected in 24.6% of the P. aeruginosa isolates. Conversely, high susceptibility rates were observed for amikacin (91.5%) and piperacillin-tazobactam (88.7%). Methicillin resistance was confirmed in 29.2% of the S. aureus strains. Logistic regression showed that a history of topical antibiotic overuse within the past 6 months was strongly associated with a ciprofloxacin-resistant strain (OR = 3.2, 95% CI = 1.5–6.8, p < 0.01). Bacterial pathogens causing CSOM exhibit high resistance to common oral and topical antibiotics, highlighting the importance of guiding therapies by ear culture results rather than empirical protocols to avoid systemic complications.

Keywords: Chronic Suppurative Otitis Media, Pseudomonas aeruginosa, Staphylococcus aureus, Antimicrobial Resistance, Ciprofloxacin Resistance, Hearing Loss

Manuscript Timeline: Received: February 02, 2025; Revised: March 11, 2025; Accepted: April 05, 2025; Published: May 14, 2025.

Citation: Cole EA, Tarawallie MZ, Okoye VN. Bacterial Pathogens and Antimicrobial Susceptibility Mapping in Patients with Chronic Suppurative Otitis Media. International Journal of Medicine and Medical Sciences, 2025, 15(5): 33–40. DOI: 10.46882/2025/IJMMS/150033

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