How NTM Infection Affects Lung Transplant Outcomes in People With Cystic Fibrosis
People with cystic fibrosis (CF) who have nontuberculous mycobacteria (NTM) infections face uncertain outcomes after lung transplant, with current evidence offering no clear picture of survival benefits or risks of post-transplant complications. While some studies suggest NTM-positive patients may survive longer post-transplant, others show persistent infection risks and conflicting data on organ rejection. Experts emphasize the need for larger, more rigorous studies to guide clinical decisions.
Cystic fibrosis, a genetic disorder that causes thick mucus buildup in the lungs, often leads to chronic infections and progressive lung damage. Lung transplantation remains a life-saving option for many with advanced CF, but the presence of NTM—a group of environmental bacteria that cause difficult-to-treat lung infections—complicates decision-making. Current guidelines recommend NTM screening and treatment before transplant, but do not exclude patients with active NTM infections.
This uncertainty stems from limited research: only four studies involving 388 adults have directly compared transplant outcomes between NTM-positive and NTM-negative CF patients. The largest study, published in 2023, found that NTM-positive patients actually survived longer post-transplant than those without NTM—but this contradicts smaller studies showing similar survival rates. Meanwhile, post-transplant NTM infection rates remain high, with some patients developing chronic disease despite pre-transplant treatment.
- No clear survival advantage/disadvantage for NTM-positive CF transplant recipients
- Post-transplant NTM infection rates: 39–78% in NTM-positive patients at transplant
- Organ rejection data conflicting: one study showed no increased risk; another reported higher chronic rejection
- Lung function decline observed in some NTM-negative patients post-transplant
- Mycobacterium abscessus was the most common NTM species identified
What the Limited Evidence Shows About NTM and Lung Transplant Survival
Three of the four reviewed studies—each involving fewer than 15 patients—reported similar survival rates between NTM-positive and NTM-negative CF transplant recipients. However, the largest study (published in JAMA Surgery), which included 182 patients, found that those with NTM infections at transplant lived longer on average than those without.
This apparent contradiction highlights the critical gap in high-quality evidence. “The data is too sparse and heterogeneous to draw definitive conclusions,” says Dr. Mark Dransfield, a CF specialist at the University of North Carolina. “We need prospective, multicenter studies with standardized follow-up to understand whether NTM status should influence transplant eligibility.”
The survival discrepancy may stem from differences in patient selection or treatment protocols. The larger study noted that patients with post-transplant NTM infections (five individuals) actually had longer survival than those without NTM post-transplant—a finding that contradicts the prevailing assumption that NTM worsens outcomes. However, the study’s authors cautioned against overinterpreting these results due to small sample sizes.
Post-Transplant NTM Infection: A Persistent Challenge
The largest study found that 39% of NTM-positive patients at transplant continued to have NTM infections post-transplant, with 22% developing chronic NTM disease. Even among patients who tested NTM-negative before transplant, 11% developed post-transplant infections, though none progressed to chronic disease. Smaller studies reported similar patterns: in one, three of five NTM-positive patients had persistent NTM after transplant.
Mycobacterium abscessus, a particularly drug-resistant NTM species, was the most commonly identified pathogen across studies. “This bacterium is notoriously difficult to treat, even with aggressive antibiotic regimens,” explains Dr. Bonnie Ramsey, director of the University of Washington CF Center. “Its presence complicates post-transplant care, as many standard immunosuppressants can’t be used due to toxicity risks.”
Current guidelines from the Cystic Fibrosis Foundation recommend pre-transplant NTM treatment, but do not exclude patients with active NTM. The International Society for Heart and Lung Transplantation (ISHLT) similarly advises individualized risk assessment rather than blanket exclusion.
Organ Rejection and Lung Function: Mixed Signals
Data on organ rejection and lung function post-transplant is even more limited. One study reported no organ rejection among five NTM-positive patients, suggesting similar rejection risks between groups. However, another study found that three of five NTM-positive patients experienced chronic rejection—a rate higher than typically observed in CF transplant populations.
Regarding lung function, a small study of nine patients found that two of four NTM-negative patients experienced deterioration, one within eight months and another at five years post-transplant. This raises questions about whether NTM clearance alone guarantees stable lung function after transplant.
Dr. Fischer notes: “The conflicting data on rejection and lung function underscores how little we understand about NTM’s long-term impact on transplant outcomes. Without better evidence, clinicians must weigh individual patient factors—such as NTM species, prior treatment response, and overall lung health—when making transplant decisions.”
Why the Evidence Is So Uncertain—and What’s Next
The studies reviewed share several methodological limitations that undermine their reliability:
- Small sample sizes: Three studies included fewer than 15 patients each
- Lack of standardization: No adjustments for age, comorbidities, or treatment variations
- Incomplete data: Some studies omitted key details like NTM species or pre-transplant treatment duration
- Short follow-up: Most studies tracked patients for fewer than five years post-transplant
Experts agree that larger, prospective studies are urgently needed. The NTM-CF Transplant Registry, launched in 2020, aims to address this gap by collecting data from CF centers worldwide. “We’re still in the dark ages of NTM research in transplant medicine,” says Dr. Dransfield. “Until we have better data, we’re essentially making decisions based on anecdotes and small studies.”
Recent developments offer some hope. A 2024 NEJM study identified potential biomarkers that may predict NTM persistence post-transplant, though these findings require validation. Meanwhile, new antibiotic combinations—such as those targeting Mycobacterium abscessus—are showing promise in reducing post-transplant infection rates.
Practical Considerations for Patients and Clinicians
For patients with CF and NTM considering transplant, the current evidence suggests:
- NTM should not automatically disqualify you from transplant evaluation, but it will influence your care plan
- Pre-transplant NTM treatment is strongly recommended, though cure rates vary by species
- Post-transplant monitoring for NTM recurrence is critical, particularly for Mycobacterium abscessus
- Discuss your specific NTM species with your transplant team, as some (like M. abscessus) pose higher risks
Clinicians face a delicate balance: NTM increases surgical risks but may also indicate advanced lung disease that makes transplant more urgent. “We’re caught between two bad options,” says Dr. Ramsey. “Delaying transplant to treat NTM may worsen lung function, while proceeding without optimal NTM control risks post-transplant complications.”
For patients, the Cystic Fibrosis Foundation’s Transplant Center Network provides resources for finding NTM-experienced transplant centers. The NTM-Net consortium also offers patient support and the latest research updates.
3 Critical Takeaways for Patients and Providers
- No definitive survival advantage: Current data shows mixed results on whether NTM status affects long-term survival post-transplant.
- High post-transplant NTM risk: Up to 39% of NTM-positive patients may continue to have NTM after transplant, with some developing chronic disease.
- Individualized assessment is key: Transplant eligibility should consider NTM species, treatment response, and overall lung health—not NTM status alone.
What’s Next in NTM and Transplant Research?
The NTM-CF Transplant Registry is recruiting patients to improve evidence quality. For the latest updates, monitor:
- The ISHLT Annual Meeting (June 2025)
- Cystic Fibrosis Foundation’s Treatment Guidelines (updated annually)
- NEJM and JAMA Surgery for new NTM-transplant studies
Have you or a loved one undergone a lung transplant with NTM? Share your experience in the comments below to help others navigate this complex decision.
About the Author
Dr. Helena Fischer is a physician and health journalist with an MD from Charité – Universitätsmedizin Berlin. As Editor of Health at World Today Journal, she specializes in translating complex medical research into accessible, evidence-based reporting. Her work has been recognized with the 2023 European Health Journalism Award.