Adenoid Microbiology: Expanded Role of Resistant S. Aureus

Abstract

Objective: 1) Learn the most common bacteria cultured from diseased adenoid tissue, 2) learn the resistance patterns of these bacteria, and 3) compare growth patterns between different patient diagnoses.

Method: Adenoid bacteriology has been implicated in multiple infectious diseases of the head and neck. We examined core adenoid tissue from patients undergoing adenoidectomy for chronic adenotonsillitis, hypertrophy with obstruction, or chronic/recurrent otitis media for aerobic and anaerobic bacteria. Further we compared the bacteria isolated (both qualitatively and quantitatively) between groups.

Results: Multiple potentially pathogenic organisms were grown, including S pneumoniae (22.4%), M catarrhalis (19.2%), and H influenzae (13.2%). Interestingly Staph aureus (32.4%) was grown in higher numbers than S pneumoniae, H influenzae, and M catarrhalis. 24.5% of S aureus isolates were methicillin resistant (MRSA, 7.8% of all patients), and 60% were penicillin resistant (19.2% of all patients). Therefore 84% of the S aureus cultured were MRSA or penicillin resistant. Qualitative and quantitative analysis of potentially pathogenic bacteria revealed no significant differences between groups. However, there was a trend for a higher number of MRSA in patients with chronic adenoiditis versus those with hypertrophy.

Conclusion: Knowledge of common bacteria and resistance patterns guides antimicrobial therapy. Amoxicillin is currently the first-line treatment for many conditions tied directly to adenoid microbiology. Therefore, the bacteria and resistance patterns of diseased adenoid tissue should be revisited with particular attention to the expanding role of resistant strains of S aureus.