The microbiology of acute mastoiditis infections presenting to a large UK tertiary paediatric ENT centre in a post-pneumococcal conjugate vaccination era.

Abstract

Objectives: Mastoiditis commonly presents to ENT services. Following the UK introduction of the 13-valent conjugate pneumococcal vaccine in 2010, changes in the organisms of these infections were hypothesised. We aim to assess the microbiological profile of patients with acute mastoiditis in our centre.

Methods: Retrospective review of patients admitted to Alder Hey Children's Hospital for mastoiditis between January 2017-September 2022. Data was collected from electronic patient records, microbiology and biochemistry reports.

Results: A total of 108 patients were admitted: 61 males and 47 females with a median age of 2 years (with a range of 4 months-14 years). A total of 82 organisms were isolated from 50 (46 per cent) children. Streptococcus spp. (22 specimens; 27 per cent) and Staphylococcus spp. (13 specimens; 16 per cent) were most common. Other organisms included Pseudomonas aeruginosa (6; 7 per cent), anaerobes (4; 5 per cent), Haemophilus influenzae (4; 5 per cent), and Fusobacterium (4; 6 per cent).

Conclusion: Mastoiditis predominantly involves gram-positive, facultative anaerobic bacteria. Empirical cefotaxime and metronidazole provide adequate coverage. Culture and sensitivity testing is essential for antibiotic stewardship.