Assessing the impact of anti-microbial showerheads on the prevalence and abundance of opportunistic pathogens in shower water and shower water-associated aerosols

Abstract

Respiratory infections from drinking water-associated pathogens that can cause infections in the immunocompromised (DWPIs) are increasing, yet knowledge of DWPI aerosolization and if dynamics are DWPI-specific is lacking. Although there are several DWPI mitigation strategies, the use of antimicrobial showerheads is one of the easiest and most economical. There are many manufacturers and designs of antimicrobial showerheads that claim to remove microorganisms from shower water, yet all fail to assess efficacy in realistic conditions. In this study, a custom-built shower laboratory housing triplicates of three different showerheads (antimicrobial filter-based, antimicrobial silver-embedded and conventional acrylonitrile butadiene styrene plastic) were used to assess the physiochemical and microbial dynamics in shower water and respirable shower water-associated aerosols (1µm – 5 µm) over the course of 84 days. Collectively, findings from the study suggest that showerheads marketed as antimicrobial produce similar chemical and DWPI water quality to non-antimicrobial showerheads (p= >0.05) when operated under real-world conditions, however marked differences in the rare microbial community were present. In addition, although there were no differences in absolute DWPI abundance between showerhead type, each DWPI peaked in concentration at a different biofilm ages, suggesting that potential DWPI inhalation risk is DWPI- specific and influenced by the number of days of operation of the showerhead.

Moving beyond silver in point-of-use drinking water pathogen control

“…Of those POU devices that are studied under conditions reflective of actual use, only the impacts the technology on microbial water quality is explored; impacts on biofilms that develop within the fixture and microbial concentrations in aerosols generated by the product during use (i.e., the most likely exposure route for respiratory infections) have only recently begun to be addressed. 62 Thus, the critical research gaps and urgent research need identified herein is (1) POU device efficacy assessments in operating conditions, (2) the use of both culture-independent and culture-dependent strategies, and (3) the assessment of antimicrobial capabilities in matrices beyond the water exiting the fixture (e.g., biofilm within POU, aerosols generated). While the rapid response capabilities and adaptability of POU treatment and mitigation makes it an important strategy for continued DWPI control, the "silver bullet" solution likely does not involve silver after all.…”

“…, the most likely exposure route for respiratory infections) have only recently begun to be addressed. 62 Thus, the critical research gaps and urgent research need identified herein is (1) POU device efficacy assessments in operating conditions, (2) the use of both culture-independent and culture-dependent strategies, and (3) the assessment of anti-microbial capabilities in matrices beyond the water exiting the fixture ( e.g. , biofilm within POU, aerosols generated).…”