Bacterial strain changes during chronic otitis media surgery

Area of Science:

• Otolaryngology
• Infectious Diseases
• Microbiology

Background:

• Antibiotic selection for chronic otitis media (COM) traditionally relies on pre-operative cultures.
• Understanding bacterial dynamics during COM surgery is crucial for effective treatment.

Purpose of the Study:

• To investigate the changes in bacterial strains within the middle ear during COM surgery.
• To assess the reliability of pre-operative cultures in guiding post-operative antibiotic choices.

Main Methods:

• Collected pre-operative bacterial cultures from middle ear swabs.
• Obtained peri-operative cultures from granulation tissue in the middle ear or mastoid cavity.
• Acquired post-operative cultures when otorrhoea developed after surgery.

Main Results:

• Bacterial growth was detected in 45.5% of pre-operative, 13.5% of peri-operative, and 4.5% of post-operative cultures.
• Methicillin-resistant Staphylococcus aureus (MRSA) was the predominant bacteria across all culture types, increasing from pre- to post-operative periods (32.4% to 71.4%).

Conclusions:

• Bacterial culture results from post-operative otorrhoea showed poor agreement with pre-operative or peri-operative findings.
• Strain re-identification is necessary for accurate post-operative treatment guidance in COM.