Clinical and microbiological profile of patients with chronic otitis media - Squamosal disease with special reference to anaerobes.

OBJECTIVES

To assess the microbiological profile of chronic otitis media (COM)-squamosal disease with special reference to anaerobic bacteria, evaluate associations with clinical features, and determine antibiotic susceptibility of anaerobic isolates.

METHODS

A prospective observational study was conducted over one year at JIPMER, Puducherry, including 60 patients diagnosed with COM-squamosal disease. Intraoperative ear discharge samples were cultured using aerobic and anaerobic techniques. Bacterial isolates were identified by MALDI-TOF-MS, and anaerobes were confirmed by aerotolerance testing. Antibiotic susceptibility was performed according to EUCAST v.15 2025 guidelines.

RESULTS

Positive cultures were obtained in 76.6 % of cases; aerobes were isolated in 95.6 %, anaerobes in 21.7 %, and fungi in 4.3 %. Polymicrobial/Mixed growth infections were observed in 45.6 % of culture-positive specimens. The predominant aerobic isolate was Pseudomonas aeruginosa, while anaerobic isolates included Bacteroides fragilis, Finegoldia magna, and Peptoniphilus asaccharolyticus. Anaerobic isolates were largely susceptible to metronidazole and carbapenems, with variable resistance patterns.

CONCLUSION

Anaerobic bacteria significantly contribute to COM-squamosal infections but are often overlooked. Routine anaerobic culture and sensitivity testing should be incorporated into diagnostic protocols to guide effective antimicrobial therapy and prevent complications.