Nontuberculous Mycobacterial Infections at a National Cancer Institute-Designated Comprehensive Cancer Center in...

Nontuberculous mycobacteria (NTM) are environmental organisms that become opportunistic pathogens in certain populations. NTM prevalence has increased globally, likely due to increased diagnostic testing and the availability of population-based studies. Current literature on oncology patients is minimal and represents a unique study area. Here we present the epidemiology and treatment of NTM infection cases at a National Cancer Institute-designated comprehensive cancer center.

We performed a retrospective single-center cohort study of adults with microbiologically proven NTM infections presenting from 2020 to 2023. Epidemiologic and treatment-related data were retrieved from the electronic medical record and evaluated to illustrate institutional patterns.

A total of 93 patients met assessment criteria, with most (74 of 93 [80%]) having a past or active cancer. Mycobacterium avium complex (47 of 93 [51%]) and Mycobacterium abscessus group (28 of 93 [30%]) were the most common isolates. The majority were pulmonary infections (75 of 93 [81%]), with the integument accounting for most extrapulmonary sites (14 of 18 [78%]). Of 93 patients, 49 (53%]) received therapy, with many (41 of 49 [84%]) receiving ≥3 agents. Thirty-nine (80%]) required an initial regimen modification, and 13 (27%) received dual β-lactam therapy (frequently including meropenem). Of treated patients, 36 (73%) demonstrated improved symptoms, 18 (37%) improved or partially improved radiologic change, and 19 (39%]) sustained culture conversion to negative at the evaluation time point; 13 (27%) died or were lost to follow-up.

Our report offers one of the largest single-center epidemiologic perspectives on NTM infections in oncology patients. It offers unique insight into treatment practices in this population, particularly regarding dual β-lactam therapy.