Hawaiian Volcanic Ash, an Airborne Fomite for Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause chronic lung disease. Within the U.S., Hawai'i shows the highest prevalence rates of NTM lung infections. Here, we investigated a potential role for active volcanism at the Kīlauea Volcano located on Hawai'i Island in promoting NTM growth and diversity. We recovered NTM that are known to cause lung disease from plumbing biofilms and soils collected from the Kīlauea environment. We also discovered viable Mycobacterium avium, Mycobacterium abscessus, and Mycobacterium intracellulare subsp. chimaera on volcanic ash collected during the 2018 Kīlauea eruption. Analysis of soil samples showed that NTM prevalence is positively associated with bulk content of phosphorus, sulfur, and total organic carbon. In growth assays, we showed that phosphorus utilization is essential for proliferation of Kīlauea‐derived NTM, and demonstrate that NTM cultured with volcanic ash adhere to ash surfaces and remain viable. Ambient dust collected on O'ahu concurrent with the 2018 eruption contained abundant fresh volcanic glass, suggestive of inter‐island ash transport. Phylogenomic analyses using whole genome sequencing revealed that Kīlauea‐derived NTM are genetically similar to respiratory isolates identified on other Hawaiian Islands. Consequently, we posit that volcanic eruptions could redistribute environmental microorganisms over large scales. While additional studies are needed to confirm a direct role of ash in NTM dispersal, our results suggest that volcanic particulates harbor and can redistribute NTM and should therefore be studied as a fomite for these burgeoning, environmentally acquired respiratory infections. Plain Language Summary Nontuberculous mycobacteria (NTM) can cause environmentally acquired lung infections in susceptible individuals. While NTM infections are linked to household exposures, there are likely non‐household routes of acquisition. Hawai'i is a geographic hotspot for NTM lung disease, but the island‐specific environmental niches for NTM remain poorly understood. Thus, a greater knowledge of where susceptible individuals acquire their infections is an important public health endeavor that may lead to actions to mitigate potential sources of NTM exposures. In the current work, we show that particulate matter collected from Kīlauea Volcano on Hawai'i Island harbors Mycobacterium avium, Mycobacterium abscessus, and Mycobacterium intracellulare subsp. c