Stenotrophomonas maltophilia has uncertain clinical significance in bronchiectasis patients. This retrospective study describes the characteristics and outcomes of this patient group. Bronchiectasis patients with S. maltophilia were identified from microbiology records and demographic data was recorded from electronic patient information. Comparisons were made to a previously prospectively collected dataset of bronchiectasis patients without S. maltophilia growth.
There were 174 patients with S. maltophilia and bronchiectasis. Intravenous and oral antibiotics were taken by 38.7% and 48.1% of the cohort respectively in the 2 months prior to the first S. maltophilia culture. Patients were followed up for a median of 6 (2–11) years and the mortality was 28.7%. Infection resolved (3 negative sputa) in 119/174 patients with recurrence of infection in 32/119. Specific treatment for the S. maltophilia was given in 91/174 patients, however treatment did not significantly affect resolution. Failure of resolution was however significantly associated with mortality (p < 0.001) (Figure 1). In the year prior to S. maltophilia culture, 12.7% grew non-tuberculosis mycobacterium (NTM). In comparison with a separate bronchiectasis cohort, those with S. maltophilia had a lower FEV1 (59.2% vs 68.4%) and there was more immunodeficiency as the underlying aetiology (10.3% vs 2.38%).
Persistent S. maltophilia has a poor outcome in bronchiectasis. It may act as a marker of disease severity and the requirement for antibiotics, and acquisition frequently follows antibiotic use. It was also associated with the isolation of NTM. The resolution of infection is common but is not related to treatment directed against the organism, however persistent infection is associated with increased mortality.