Nontuberculous Mycobacterial Disease and Molybdenum in Colorado Watersheds

Abstract

Nontuberculous mycobacteria (NTM) are environmental bacteria that may cause chronic lung disease. Environmental factors that favor NTM growth likely increase the risk of NTM exposure within specific environments. We aimed to identify water-quality constituents (Al, As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Se, Na, Zn, and pH) associated with NTM disease across Colorado watersheds. We conducted a geospatial, ecological study, associating data from patients with NTM disease treated at National Jewish Health and water-quality data from the Water Quality Portal. Water-quality constituents associated with disease risk were identified using generalized linear models with Poisson-distributed discrete responses. We observed a highly robust association between molybdenum (Mo) in the source water and disease risk. For every 1- unit increase in the log concentration of molybdenum in the source water, disease risk increased by 17.0%. We also observed a statistically significant association between calcium (Ca) in the source water and disease risk. The risk of NTM varied by watershed and was associated with watershed-specific water-quality constituents. These findings may inform mitigation strategies to decrease the overall risk of exposure.

Nontuberculous mycobacterial infection and environmental molybdenum in persons with cystic fibrosis: a case–control study in Colorado

“…These county-level probabilities of infection suggest that potential sources of NTM exposure may come through municipal water systems that take water from these rivers as well as possibly from crop irrigation. The results shown in this map reflect the same high-risk regions that we have reported previously [11].…”

“…For every 1-log unit increase in molybdenum concentration in surface water among pwCF, the odds of NTM infection caused by M. abscessus species increased by 79% compared with those who were NTMnegative (Table 3; Model 2). As discussed previously [11], molybdenum is involved in the essential metabolism of M. tuberculosis [12][13][14], and, given the genetic relatedness of these organisms, it is biologically plausible that it may play a similar role in NTM metabolism [24]. In this study, we replicated the molybdenum-NTM infection association in a CF population with water-quality constituent median values calculated for county line boundaries (instead of watershed boundaries [11]).…”

“…As discussed previously [11], molybdenum is involved in the essential metabolism of M. tuberculosis [12][13][14], and, given the genetic relatedness of these organisms, it is biologically plausible that it may play a similar role in NTM metabolism [24]. In this study, we replicated the molybdenum-NTM infection association in a CF population with water-quality constituent median values calculated for county line boundaries (instead of watershed boundaries [11]). This study also goes a step further to suggest that molybdenum in surface water may increase the odds of acquiring NTM, specifically for M. abscessus infection, rather than for MAC infection, in a CF population.…”

“…We obtained water-quality data from the WQP [15], a water-quality database collected or hosted by the U.S. Geological Survey, the U.S. Environmental Protection Agency, and the National Water Quality Monitoring Council. Our water-quality dataset has been described previously [11]. Supplementary Table 2 presents the median and standard deviation values of the water-quality constituents obtained from the WQP that were used in our analyses.…”

“…In two previous studies, we explored the role of water exposure in NTM risk. We identified three high-risk watersheds in Colorado [10], and further used source water data [11] to identify factors potentially influencing the higher risk in these watershed regions. Molybdenum in surface water was a significant contributor to the risk of NTM infection; a 1-unit increase in the log concentration of molybdenum in surface water was associated with a 17% increased risk of NTM infection.…”