TOPLINE

Among lung transplant recipients, isolating nontuberculous mycobacteria (NTM) from the lungs within the first year after a transplant was linked to higher risks for death or a repeat transplant, and to a higher risk for chronic lung allograft dysfunction, with the former driven by rapid-growing species and the latter by slow-growing species.

METHODOLOGY

• Researchers conducted a cohort study to assess whether early isolation of NTM from lungs was associated with a higher risk for death or a repeat transplant and with chronic lung allograft dysfunction in lung transplant recipients.
• They analyzed 1766 adult recipients (median age at transplant, 60 years; 41% women) who underwent a lung transplant between 2007 and 2022 at five US centers.
• Early NTM isolation was defined as NTM growth from lung samples within 365 days of transplantation; species were classified as rapid-growing (culture growth of 7 days or less) or slow-growing (culture growth of more than 7 days).
• The primary outcome was the time from transplant to death or a repeat transplant. The secondary outcome was the time to development of chronic lung allograft dysfunction, assessed using spirometry.
• The median follow-up duration was 5 years.

TAKEAWAY

• Overall, 13% (n = 223) of the recipients had NTM isolated in the first year, with a median time to first isolation of 61 days.
• Early NTM isolation was linked to a 30% higher risk for death or a repeat transplant (adjusted hazard ratio [aHR], 1.30; 95% CI, 1.05-1.60). Fast-growing species carried a markedly higher risk (aHR, 2.17; 95% CI, 1.42-3.31).
• Chronic lung allograft dysfunction was developed in 44% (n = 718) of the recipients. Early NTM isolation was also associated with a greater risk for the condition (aHR, 1.29; 95% CI, 1.03-1.62).
• The association with chronic lung allograft dysfunction was statistically significant only for slow-growing species (aHR, 1.33; 95% CI, 1.04-1.69) and appeared strongest among recipients with interstitial lung disease.

IN PRACTICE

"Better characterization of pretransplant NTM susceptibility may improve risk stratification and inform posttransplant surveillance and management," the authors wrote.

SOURCE

The study was led by Gabrielle Mezochow, MD, University of Pennsylvania, Philadelphia. It was published online on August 31, 2026, in The Journal of Heart and Lung Transplantation.

LIMITATIONS

The reasons for sampling and how often cultures were taken varied across patients. Imaging and clinical symptom data were not available, so the researchers could not determine who had clinical disease. Moreover, long-term information on immunosuppressive therapy, antibiotic treatment, and gastroesophageal reflux were unavailable.

DISCLOSURES

The study was supported by grants from the National Heart, Lung, and Blood Institute. Several authors reported receiving institutional funding and consulting fees from various organizations, including the Cystic Fibrosis Foundation, Gift of Life Transplant Foundation, and pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.