Clinical associations with carriage of pulmonary Stenotrophomonas maltophilia.

Abstract

Stenotrophomonas maltophilia causes opportunistic respiratory infections and is associated with declining lung function in patients with cystic fibrosis (CF). Risk factors for carrying S. maltophilia remain unclear. We conducted a retrospective study of patients yielding ⩾1 respiratory S. maltophilia isolate at the Oxford University Hospitals Trust between 2014 and 2019 and a cohort study of S. maltophilia carriage in CF patients attending annual review in 2018. Seven hundred and forty isolates were identified from 238 patients (median 1.0 isolate/patient). Predisposing conditions included invasive ventilation (29.8%), CF (25.6%) and non-CF bronchiectasis (24.4%). The rates of Stenotrophomonas isolates and co-trimoxazole resistance were stable over time. About 10.8% of isolates were co-trimoxazole-resistant, with resistance more common in CF than in other diagnoses (29.5% vs 5.8%, p < 0.001). No clinical features were significantly associated with S. maltophilia carriage in the CF population. We present new insight into the epidemiology of Stenotrophomonas colonisation/infection and identify increased co-trimoxazole resistance in CF isolates.