Incidence and outcomes of Mycobacterium abscesssus infections in non-Cystic Fibrosis patients

Over recent years the incidence of <i>Mycobacterium abscessus</i> infection has been increasing in patients with Cystic Fibrosis (CF). The reason for this increase is far from clear; in our patients with CF in Leeds ten per cent of all adult patients have cultured <i>M. abscessus</i>. We were keen to explore the incidence retrospectively in non-CF patients and whether any correlations could be identified. Between 2010 and 2018 we identified patients who had cultured positive for <i>M. abscessus</i> on respiratory samples. Seventeen patients were identified as having repeated positive cultures. There was no evidence of increasing incidence over this period. All seventeen patients presented with increased cough, five (29%) also had significant haemoptysis. On CT scan 4/15 (27%) had nodules or tree in bud changes and 6/15 (40%) cavitation. Two patients did not have a CT scan. Eight patients had a history of chronic respiratory disease (4 COPD, 2 pulmonary fibrosis, and 2 asthma). Three patients were immunocompromised (2 autoimmune disease and 1 leukaemia). Interestingly, 14/17 (82%) had a strong history of gastroesophageal reflux disease and were receiving proton pump inhibitors. Three patients (18%) had coeliac disease. Only three patients had evidence of progressive <i>M. abscessus</i> infection requiring treatment, one of these died. In the other 14 patients only 3 patients had long term positive samples with 11 (65%) clearing the <i>M. abscessus</i> without treatment. In conclusion, the incidence of <i>M abscessus</i> does not seem to be increasing in non-CF patients in our institution. There may be an epidemiological link with acid suppression and reflux disease, this hypothesis has been previously reported in patients with CF.