Outcome according to subspecies following lung transplantation in cystic fibrosis pediatric patients infected with Mycobacterium abscessus.

Background: Mycobacterium abscessus infection has been associated with variable outcomes following lung transplantation. M abscessus comprises three subspecies (M abscessus subsp abscessus, M abscessus subsp massiliense, and M abscessus subsp bolletii). We investigated whether lung transplantation outcome in cystic fibrosis (CF) patients in a single center was related to the M abscessus subspecies and genetic cluster.

Methods: CF patients with chronic M abscessus infection transplanted at Great Ormond Street Hospital between 2004 and 2017 were retrospectively examined. All M abscessus isolates were identified to subspecies level by polymerase chain reaction and sequencing. Genetic cluster was determined by variable number tandem repeat profiling and whole-genome sequencing (WGS), and sequence type inferred from WGS.

Results: Thirteen patients with chronic M abscessus infection underwent heart/lung or lung transplantation. Subspecies identification showed n = 1 with M abscessus bolletii, n = 5 with M abscessus massiliense, and n = 7 with M abscessus abscessus infection. Eight (62%) patients (one with M abscessus massiliense and seven with M abscessus abscessus) died post-lung transplant. The patient with M abscessus bolletii and three patients with M abscessus massiliense did well post-transplant. One patient with M abscessus massiliense is receiving ongoing treatment.

Conclusions: Dramatically worse outcomes are observed in patients infected with M abscessus subspecies abscessus, the majority of whom were infected with ST-1 and ST-26 strains. Patients infected with other M abcsessus strains can have acceptable outcomes.