Clinical outcomes of lung transplant recipients with pre-transplant Mycobacterium avium complex infection.

Background: Lung transplant recipients (LTRs) are at risk for Mycobacterium avium complex (MAC) infections, in part due to the presence of structural lung disease pre-transplant and relatively higher levels of immunosuppression post-transplant. There is a lack of data regarding outcomes of LTR with MAC infections pre-transplant.

Methods: This is a single-center retrospective analysis of patients who received lung transplants (LTs) from 2013 to 2020 with 1) evidence of MAC on culture or polymerase chain reaction before or at the time of transplant or 2) granulomas on explant pathology and positive acid-fast bacillus stains with no other mycobacteria identified. Patients were deemed to have MAC pulmonary disease (MAC-PD) if they met the American Thoracic Society/Infectious Disease Society of America criteria.

Results: Fourteen patients (14/882, 2%) met inclusion criteria. Seven patients (7/14, 50%) had pre-transplant MAC-PD, four of whom had cavitary disease. None of the 14 patients had smear-positive cultures at the time of transplant. Two patients in our cohort received treatment for MAC before transplant. Thirteen patients were bilateral LTR (13/14, 93%). One single LTR was the sole patient to receive MAC treatment post-transplant. No patients developed MAC-PD after transplant.

Conclusion: The bilateral LTR in our cohort did not develop MAC-PD despite not receiving MAC treatment post-transplant. It is possible source control was achieved with native lung explantation. Our observations suggest patients may not uniformly require pre- or post-transplant MAC treatment if they are smear-negative and undergo bilateral LT.