Microbiological Investigation and Virulence Factor Characterization of Chronic Suppurative Otitis Media in A Nigerian Tertiary Hospital

Background: Chronic suppurative otitis media (CSOM) is a common cause of hearing loss with the attendant poor academic performance and low productivity in workplaces. Objectives: This study investigated the microbial aetiology and associated virulence mechanisms of CSOM in a Nigerian tertiary hospital.  Methods: This was a prospective study of 52 patients diagnosed with CSOM in either one or both ears who had not taken any antibiotics for at least the last seven (7) days. Ear swabs were taken by an otolaryngologist and sent to the Microbiology Department for processing. The specimens were cultured within 30 min of collection and the isolates identified using standard microbiological techniques. Selected virulence properties were characterised. Results: The most common organism isolated was Staphylococcus aureus 18 (34.6%) followed by Pseudomonas aeruginosa 14 (26.9%). Fungal isolates were recovered from 6 11.5%) of specimens; in 11 (21.15%) of cases no microbe was detected. Age did not significantly affect incidence of CSOM of microbial origin (p = 0.1742) although most cases were in the age 31-40 years group. Male and female patients were almost equally affected (M: F = 1:1.08), DNase followed by biofilm formation were the predominant virulence phenotypes identified while coagulase, followed by haemolysin production, were least common.  Conclusion: Staphylococcus aureus and Pseudomonas aeruginosa were the most common organisms among CSOM cases and recovered from all age-groups. Early detection and infection control are key to reducing incidence of CSOM.