Nasopharynx as a microbiologic reservoir in chronic suppurative otitis media: preliminary study

The present study was designed to identify the correlations of bacterial strains of the middle ear and the nasopharynx in chronic suppurative otitis media (CSOM) patients who were scheduled for operations.

Sixty-three patients with CSOM were enrolled in the study. Culture specimens were collected from the middle ear and nasopharynx of patients who were admitted for operation. Samples collections were performed 3 times; from the middle ear and nasophaynx at the admission day, from the middle ear during the operation, and from the external auditory canal post-operatively. Bacteria were identified by gram staining and biochemical tests. The correspondence rate of organisms which simultaneously exist in the middle ear and the nasopharynx was measured.

Sixty-eight organisms were isolated from the middle ear and 57 organisms from the nasopharynx among 63 patients. Of 68 bacteria identified in middle ear, 26.52% (18 bacteria) corresponded with those of nasopharynx. MRSA had the high correspondence rate, and of 18 methicillin-resistant Staphylococcus aureus (MRSA) isolated from middle ear, 33.3% (6 bacteria) corresponded with nasophaynx. Meanwhile, 3 organisms of MRSA were detected from the external auditory canal post-operatively, although they were only found in nasopharynx pre-operatively.

The current trend of middle ear swab alone for bacterial detection would be insufficient to identify the potent MRSA and impede early antibiotic intervention for the effective middle ear surgery. Therefore, it is necessary to perform nasopharynx cultures together with conventional middle ear culture to control potent risk for infection pre-operatively.