Do CT findings of Mycobacterium abscessus infection in patients with Cystic Fibrosis predict outcome?

Acquisition of <i>Mycobacterium abscessus</i> is a major issue for a patient with Cystic Fibrosis (CF). Positive cultures are a contraindication for lung transplantation in the UK and recent evidence suggests substantial lung decline associated with infection. As a result of this attempts at eradication have been performed in the majority of patients. Unfortunately, <i>M. abscessus</i> is highly resistant and the success of eradication is very unpredictable. In this retrospective study we aimed to correlate the CT findings with the rates of eradication and overall outcome. All patients were cared for at the Regional Adult CF Unit in Leeds, UK. Patients were included if they were positive for <i>M. abscessus</i> on more than one occasion and had a CT scan performed. All information was collected from our electronic patient records (EMIS) system. In total 56 patients since 2008 were culture positive for <i>M. abscessus</i> on more than one occasion, of these 51 had CT scans performed. CT scan abnormalities included bronchiectasis (98%), nodules or tree-in-bud changes (76%), and cavities or pleural changes (12%). Forty-seven patients underwent eradication treatment and 24 (51%) of patients cleared the <i>M. abscessus</i> long term. In patients who had cavities or pleural changes only 17% were able to eradicate the infection. In keeping with this, patients with cavities or pleural changes appeared to have more marked clinical decline compared with patients with bronchiectasis and nodules. In conclusion, with advanced radiological changes the less likely it is to eradicate <i>M. abscessus</i> and the more rapid the clinical decline.