Ecological analyses of mycobacteria in showerhead biofilms and their relevance to human health

Abstract

45Bacteria within the genus Mycobacterium can be abundant in showerheads, and the inhalation of aerosolized mycobacteria while showering has been implicated as a mode of transmission in nontuberculous mycobacterial (NTM) lung infections. Despite their importance, the diversity, distributions, and environmental predictors of showerhead-50 associated mycobacteria remain largely unresolved. To address these knowledge gaps, we worked with citizen scientists to collect showerhead biofilm samples and associated water chemistry data from 656 households located across the U.S. and Europe. Our cultivationindependent analyses revealed that the genus Mycobacterium was consistently the most abundant genus of bacteria detected in residential showerheads, yet mycobacterial diversity 55 and abundances were highly variable. Mycobacteria were far more abundant, on average, in showerheads receiving municipal versus well water, and in U.S. households as compared to European households, patterns that are likely driven by differences in the use of chlorine disinfectants. Moreover, we found that water source, water chemistry, and household location also influenced the prevalence of specific mycobacterial lineages detected in 60 showerheads. We identified geographic regions within the U.S. where showerheads have particularly high abundances of potentially pathogenic lineages of mycobacteria and these 'hot spots' generally overlapped with those regions where NTM lung disease is most prevalent. Together these results emphasize the public health relevance of mycobacteria in showerhead biofilms. They further demonstrate that mycobacterial distributions in 65 showerhead biofilms are often predictable from household location and water chemistry, knowledge that advances our understanding of NTM transmission dynamics and the development of strategies to reduce exposures to these emerging pathogens.Introduction:

Global Environmental Nontuberculous Mycobacteria and Their Contemporaneous Man-Made and Natural Niches

“…In a recent large-scale study, researchers partnered with a network of citizen scientists to collect showerhead biofilm samples from 606 households across 49 of 50 U.S. states to simultaneously superimpose the identities of showerhead microbes over geographic areas where NTM-LD is most prevalent (Gebert et al, 2018). Multiple concluding findings were reported that reinforce known paradigms.…”

Exacerbation of Mycobacterium avium pulmonary infection by comorbid allergic asthma is associated with diminished mycobacterium-specific Th17 responses

“…Nontuberculous mycobacteria (NTMs) are a collection of mycobacterial species other than the Mycobacterium tuberculosis (Mtb) complex and Mycobacterium leprae. NTMs have emerged as representative opportunistic pathogens that are ubiquitous [1,2]. The global prevalence of NTM infection has recently increased, and the number of patients with NTM-associated pulmonary diseases (NTM-PDs) has gradually increased [3,4].…”

Human‐ and infrastructure‐associated bacteria in greywater

“…Amplicon sequencing has increasingly been adopted to gain a more comprehensive understanding of microbial communities in different environments. This technique has been used extensively with sewage (Shanks et al 2013) and drinking water infrastructure (Ji et al 2015), but only more recently used to characterize greywater (Callewaert et al 2015;Macedo et al 2017;Troiano et al 2018;Truu et al 2019) and associated biofilms (Feazel et al 2009;Dalahmeh et al 2014;Rodr ıguez-Mart ınez et al 2016;Gebert et al 2018). The 16S ribosomal RNA subunit gene is commonly used to characterize prokaryotic taxonomic diversity based on the variability present across ribosomal subunit prokaryotic genomes.…”