Nosocomial sinusitis with isolation of anaerobic bacteria in ICU patients

Objective: To determine the frequency and the eventual clinical characteristics of nosocomial sinusitis with anaerobic bacteria isolation in patients in the intensive care unit (ICU). Design: Retrospective study. Setting: A 12-bed medical ICU in a teaching hospital. Patients: 30 adult patients with documented nosocomial maxillary sinusitis. Interventions: None. Measurements and results: Using appropriate microbiological techniques, 33 anaerobic bacterial strains were isolated in 18/30 patients (60 %) with nosocomial sinusitis. Anaerobic bacteria were associated with aerobic strains in 13 patients (72 %), whereas in 5 patients (28 %) only anaerobic strains were isolated in sinus puncture cultures. The most frequently isolated species were Prevotella sp. (n = 20, 60 %) and Fusobacterium nucleatum (n = 5, 15 %). The production of beta-lactamase was demonstrated in 13/27 gram-negative anaerobic bacteria. All patients in whom anaerobic bacteria were isolated from transnasal punctures had had a nasogastric tube. Patients in whom anaerobic bacteria were isolated more frequently had neurological disorders upon admission (p < 0.02). Ten patients (30 %) had nosocomial pneumonia, 8 of whom had at least one identical strain in both lung and sinus cultures, including 2 patients with anaerobic bacteria isolation. Conclusions: Using appropriate microbiological techniques, anaerobic bacteria were frequently isolated in nosocomial sinusitis. If necessary, the empirical choice of antimicrobial therapy in patients with nosocomial sinusitis should take into account these results.