Droplet distribution and airborne bacteria in an experimental shower unit

Estrada-Pérez, Carlos E.; Kinney, Kerry A.; Maestre, Juan P.; Hassan, Yassin A.; King, Maria D.

doi:10.1016/j.watres.2017.11.039

Cited by 26 publications

(17 citation statements)

References 54 publications

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“…Our study shows similarities and complementarities with 2 other recent studies from Chattopadhyay et al (Chattopadhyay et al, 2017) and Estrada-Perez et al (Estrada-Perez et al, 2018) in term of aerosol samplers, Gram-negative bacillus targets, and detection methods. Table 4 shows that the concentrations of Legionella aerosols generated by the vibrating-mesh nebulizer (8.9 x 10 3 CFU.m 3 ) or by the jet nebulizer (1.4 x 10 3 CFU.m 3 .min -1 ) in our experimental setup effectively mimic an emitted dose of shower bacteria.…”

Section: Discussionsupporting

confidence: 79%

“…Regarding aerosol dispersion (quantity, size), the discrepancy between the results from the different studies is due to the different methods and apparatuses used to measure the air bacteria concentration and to numerous other factors, such as ambient humidity, type of shower stall, design of the showerhead, water temperature, piping materials, human occupants or bacterial communities and biofilm development. Several publications (Chattopadhyay et al, 2017;Cowen and Ollison, 2006;Estrada-Perez et al, 2018;O'Toole et al, 2009;Perkins et al, 2009;Zhou et al, 2007) have shown that (i) a shower with the low-flow showerhead generates a significantly higher number of aerosols than a high-flow shower. (ii) A hot shower (approximately 40°C) increases the rate of evaporation; therefore, the number of small particles within the breathable range is increased, and the culturability of cells is decreased with the turn off to the VBNC state, as shown for Pseudomonas and Legionella.…”

Section: Discussionmentioning

confidence: 99%

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A valuable experimental setup to model exposure to Legionella’s aerosols generated by shower-like systems

et al. 2020

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The mechanism underlying Legionella aerosolization and entry into the respiratory tract remains poorly documented. In previous studies, we characterized the aerodynamic behaviour of Legionella aerosols and assessed their regional deposition within the respiratory tract using a human-like anatomical model. The aim of this study was to assess whether this experimental setup could mimic the exposure to bioaerosols generated by showers. To achieve this objective we performed experiments to measure the mass median aerodynamic diameter (MMAD) as well as the emitted dose and the physiological state of the airborne bacteria generated by a shower and two nebulizers (vibrating-mesh and jet nebulizers). The MMADs of the dispersed bioaerosols were characterized using a 12-stage cascade low-pressure impactor. The amount of dispersed airborne bacteria from a shower was quantified using a Coriolis® Delta air sampler and compared to the airborne bacteria reaching the thoracic region in the experimental setup. The physiological state and concentration of airborne Legionella were assessed by qPCR for total cells, culture for viable and cultivable Legionella (VC), and flow cytometry for viable but noncultivable Legionella (VBNC). In summary, the experimental setup developed appears to mimic the bioaerosol emission of a shower in terms of aerodynamic size distribution. Compared to the specific case of a shower used as a reference in this study, the experimental setup developed underestimates by 2 times (when the jet nebulizer is used) or overestimates by 43 times (when the vibrating-mesh nebulizer is used) the total emitted dose of airborne bacteria. To our knowledge, this report is the first showing that an experimental model mimics so closely an exposure to Legionella aerosols produced by showers to assess human lung deposition and infection in well-controlled and safe conditions.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

A valuable experimental setup to model exposure to Legionella’s aerosols generated by shower-like systems

et al. 2020

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“…Despite these stressors, bacterial abundances often exceed 10 6 cells cm −2 inside shower plumbing ( 1 – 3 ). Thus, in the act of showering, we are exposed to elevated concentrations of showerhead-associated bacteria as they are dislodged and aerosolized ( 4 – 6 ).…”

Section: Introductionmentioning

confidence: 99%

Ecological Analyses of Mycobacteria in Showerhead Biofilms and Their Relevance to Human Health

Gebert

Delgado‐Baquerizo

Oliverio

et al. 2018

mBio

110

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Bacteria thrive in showerheads and throughout household water distribution systems. While most of these bacteria are innocuous, some are potential pathogens, including members of the genus Mycobacterium that can cause nontuberculous mycobacterial (NTM) lung infection, an increasing threat to public health. We found that showerheads in households across the United States and Europe often harbor abundant mycobacterial communities that vary in composition depending on geographic location, water chemistry, and water source, with households receiving water treated with chlorine disinfectants having particularly high abundances of certain mycobacteria. The regions in the United States where NTM lung infections are most common were the same regions where pathogenic mycobacteria were most prevalent in showerheads, highlighting the important role of showerheads in the transmission of NTM infections.

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“…For instance, virulence factors are not sufficiently characterized, there is a paradoxical dose-response relationship in connection with the internalization of Legionella by amoebae [ 1 ], and the role of aerosols formed during showering and the importance of exposure to this source in private homes are unclear [ 20 ], [ 21 ]. There are studies that deal experimentally with the formation and distribution of drops and aerosols formed during showering [ 27 ] as well as with mathematical exposure-risk models [ 28 ], [ 29 ], but due to the rather theoretical nature of the question, no pragmatic conclusions can be drawn from this. In Germany, unlike in other countries, air conditioning systems are of less importance as a reservoir in private households and thus as a source of infection.…”

Section: Resultsmentioning

confidence: 99%

Can mandatory monitoring in rental apartments effectively prevent legionellosis? A retrospective analysis of data from Regensburg with a review of the literature

Lampl¹,

Lang²,

Wodnick³

2020

GMS Hygiene and Infection Control; 15:Doc14

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Droplet distribution and airborne bacteria in an experimental shower unit

Cited by 26 publications

References 54 publications

A valuable experimental setup to model exposure to Legionella’s aerosols generated by shower-like systems

A valuable experimental setup to model exposure to Legionella’s aerosols generated by shower-like systems

Ecological Analyses of Mycobacteria in Showerhead Biofilms and Their Relevance to Human Health

Can mandatory monitoring in rental apartments effectively prevent legionellosis? A retrospective analysis of data from Regensburg with a review of the literature

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