How does nontuberculous mycobacteria infection affect lung transplant in people with cystic fibrosis?

Key messages

• There is some very limited evidence to inform decision-making, but this is very uncertain.

• There are worries that people with cystic fibrosis (CF) and nontuberculous mycobacteria (NTM) might not live as long after transplant as those with CF without NTM, but we found no clear evidence about how NTM affects survival after lung transplant.

• Future studies are needed to show the effects of NTM in people with CF undergoing lung transplant on survival, the risk of later developing NTM disease, and organ rejection.

What is cystic fibrosis?

Cystic fibrosis (CF) is a common, inherited condition where mucus is not cleared well from the lungs. This leads to infection and a steady loss of lung function. People with CF may be considered for a lung transplant if their lung function is poor and rapidly declining. Transplant may improve a person's quality and duration of life.

What are nontuberculous mycobacteria?

Nontuberculous mycobacteria (NTM) are germs commonly found in the environment and cause lung disease in people with CF, which can be difficult to treat. NTM infection is thought to lead to worse outcomes for people undergoing lung transplant. Whilst guidelines recommend testing and treating people with CF for NTM before lung transplant, NTM infection should not be a reason not to transplant.

What did we want to find out?

We wanted to know the effects of NTM on lung transplant in people with CF.

What did we do?

We searched for studies of people with CF (of any age) with or without NTM lung infection who were being considered for lung transplant. We also looked for studies of people with CF and NTM who either did or did not undergo a lung transplant. Our main outcomes of interest were survival, post-transplant NTM infection, time to rejection of the transplanted lungs, and quality of life; additional outcomes of interest were lung function, flare-ups of disease, weight and height.

What did we find?

We included four studies reporting on 388 adults, three with fewer than 15 relevant participants each and one larger one. Mycobacterium abscessus was the most common NTM infection identified. All four studies compared people with CF and NTM infection to people with CF and no NTM infection undergoing lung transplant. All studies reported on survival and post-transplant NTM infection; two studies reported on organ rejection; and one commented on lung function in general. We are very uncertain of the effects of lung transplant on any of the outcomes listed below.

Main results

Survival

The three smaller studies all reported similar length of survival between people with CF and NTM infection and those without NTM at transplant. The larger study found that people with CF who had NTM infection when transplanted survived longer than those with no NTM infection at transplant. This study also reported that the five people who had post-transplant NTM infection survived longer on average than the 141 participants without NTM infection post-transplant.

Post-transplant NTM infection

The largest study found that seven out of 18 participants who had NTM infection at transplant continued to have infection post-transplant and four developed NTM disease (long-term infection); 10 of the 89 participants who did not have NTM infection at transplant went on to develop it after transplant (but none had NTM disease). There were 39 people transplanted for whom there was no information on NTM infection status at transplant; three of these people had NTM infection post-transplant, and one developed NTM disease. The remaining small studies reported that NTM was found post-transplant in three out of 13 participants in one study (four were positive before transplant); one out of five participants in a second study (all of whom were positive before transplant); and two out of nine participants in the third study (five participants had NTM disease at the time of transplant).

Time to rejection

One study reported that none of the five NTM-positive CF transplant recipients experienced organ rejection, with the risk of rejection appearing similar between the NTM and the non-NTM group. The second study only stated that three out of five transplant recipients with NTM disease were reported to have chronic organ rejection.

Lung function

One study (9 participants) reported that two out of the four participants who were NTM-negative at transplant had poor or deteriorating lung function, one at eight months and one at five years post-transplant.

What are the limitations of the evidence?

None of the studies we found reported any data we could analyse. The studies did not make any adjustments to allow for age, additional treatments, or any variation in severity of disease in the people they reported on. The characteristics of the people in the comparator groups were not always clear. For these reasons, we have very low confidence in the available evidence.

How up-to-date is this evidence?

The evidence is current to 17 February 2026.