BACKGROUND. Nontuberculous mycobacteria (NTM) may colonize or infect lung transplant patients. Due to differences in populations studied and geographical diversity of NTM, risk factors for infection and its impact on patient/graft outcomes following lung transplant are conflicting in the literature. The goal of this study was to characterize the local epidemiology of NTM infection/colonization and assess the association between infection/colonization and the outcomes of mortality and chronic lung allograft dysfunction (CLAD). METHODS. This was a retrospective study including all adults undergoing first lung or heart-lung transplant at the University of Alberta (Edmonton, Canada) between January 2005 and December 2014. We extracted data on positive NTM cultures from the Alberta Provincial Laboratory mycobacteriology database, the only lab in the province that does mycobacterial culture. We compared cases with positive cultures pre- and post-transplant to those without. RESULTS. 375 patients underwent first lung transplant of which, 26 had NTM isolated before transplant. After transplant, 4 of these patients had the same strain of NTM isolated at a median of 5.5 days. An additional 12 patients had NTM isolated for the first time posttransplant at a median of 148.5 days. The most commonly isolated species was MAC (n=18), followed by M. abscessus (n=7). By Cox-regression, there was no significant difference in survival in those with or without NTM. Risk factors pre-transplant included a diagnosis of cystic fibrosis (CF) and lower body mass index (BMI); these were not associated posttransplant NTM isolation. There was no significant difference in CLAD between those with pretransplant NTM and those without. Isolation of NTM posttransplant was significantly associated with CLAD diagnosis at 5 years (p=0.037). This association was only significant with the obstructive, not the restrictive, phenotype of CLAD. Of the 16 with NTM isolation post, 10 developed CLAD; 5 had NTM isolated a median of 1073 days prior to CLAD onset while 5 had NTM isolated at a median of 287 days following CLAD onset. CONCLUSIONS. Risk factors for NTM pre-transplant were CF and BMI. NTM isolation, pre or post, was not associated with increased mortality after lung transplant. However, a diagnosis of obstructive CLAD at 5 years was significantly associated with posttransplant NTM isolation. Larger studies are needed to clarify the relationship between posttransplant NTM and CLAD.

CITATION INFORMATION: Friedman D., Cervera C., Halloran K., Tyrrell G., Doucette K. Nontuberculous Mycobacteria in Lung Transplant Recipients: Prevalence, Risk Factors and Impact on Survival and Graft Function Am J Transplant. 2017;17 (suppl 3).

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