Prevalence of Environmental Nontuberculous Mycobacteria at a Hawai'i Cystic Fibrosis Center

Abstract Rationale: Within the United States (US), Hawai'i has both the highest incidence and prevalence of pulmonary nontuberculous mycobacteria (NTM) infections. NTM colonize soil, dust, and water and form fastidious biofilms on surrounding surfaces. The modes of human acquisition of NTM are under continued investigation, but inhalation of NTM-enriched soil particulates, dust fomites, and aerosolized water droplets are recognized sources of concern. Identification of healthcare-associated transmission and acquisition has been reported, including within cystic fibrosis (CF) care centers. The CF Foundation (CFF) recommends annual surveillance for NTM, as people with cystic fibrosis (pwCF) are especially vulnerable and infections are associated with a rapid decline in pulmonary function. NTM in the healthcare system may be a source of environmental acquisition for pwCF. Our study begins to characterize the risk of NTM exposure and acquisition at Tripler Army Medical Center (TAMC), Hawai'i's only CFF-accredited care center, compared to previously observed community exposure. The primary study endpoint is to identify the prevalence and diversity of NTM species in dust and water biofilms within a Hawai'i-based CFF care center. Methods: From September 3-17, 2023, 292 samples were collected from patient rooms and clinical spaces where pwCF receive care at TAMC, as well as from common areas with which they might interact. Vent dust (n=152) and water biofilms (n=140; including sinks, showers, faucets, water fountains) were sampled and microbiologically cultured for viable NTM. Isolates were identified through amplification and sequencing of the RNA polymerase beta subunit (rpoB) gene. Results: Of 292 samples collected, 31 were positive for NTM (10.6%, 31/292). M. chimaera and M. gordonae were the most frequently isolated species, with both isolated from 9 of the 31 positive samples (29%, 9/31). 13 of the positive samples (42%, 13/31) speciated to clinically relevant NTM (9 M. chimaera, 1 M. abscessus, 3 M. chelonae). All positive samples for clinically relevant species were exclusively from water biofilms. The following NTM species were only identified in Hawai'i: M. alvei, M littorale, and M. timonense.Conclusions: TAMC's NTM recovery was lower than previous results from non-healthcare and natural environmental sampling in Hawai'i but with a similar species distribution. However, the NTM recovery rate at TAMC was similar to CF centers from the continental US. TAMC's prevalence is higher than healthcare-based sampling done in Colorado and Vermont and lower than data from Texas (Figure 1). Future studies will investigate the relatedness between healthcare environmental and respiratory NTM collected at TAMC.