Significance of Nontuberculous Mycobacteria Detection in Liver Transplant Recipients: A Descriptive Epidemiology

Nontuberculous mycobacteria (NTM) disease is a significant morbidity in solid organ transplant recipients. Its management needs to be individualized based on factors including the potential drug-related adverse effects, which is a particular concern for liver transplant (LTx) recipients. We aim to investigate the incidence proportion, clinical presentation, management, and outcome of NTM isolation and NTM diseases in our LTx recipients.

We conducted a single-center retrospective study in Japan. We included all LTx recipients with age ≥ 18 who had posttransplant mycobacterial microbiological testing of any clinical specimens between April 2005 and March 2022. Participants with NTM isolation who satisfied the diagnostic criteria in American Thoracic Society/Infectious Disease Society of America (ATS/IDSA) guidelines were defined as having NTM diseases. We collected demographic, clinical, microbiological, and radiographic data of participants through chart reviews.

Of all 472 LTx recipients, 115 received at least one mycobacterial microbiological test, of whom 15 had positive test results. Six participants had an NTM disease, all of which were pulmonary infections (6/472: 1.3%). None of them received treatment for NTM diseases, even when alternative diagnoses were absent. Except for one patient who died of posttransplant lymphoproliferative disorder, five remained free of exacerbation of NTM disease and were alive at the end of the study period, with 1067-4825 days of follow-up periods.

Late-onset pulmonary NTM diseases meeting ATS/IDSA criteria may be safely observed without treatment in selected LTx recipients. Diagnostic criteria may need to be tailored for immunocompromised patients including LTx recipients to help guide the management.