Pseudomonas aeruginosadose response and bathing water infection

Abstract

Pseudomonas aeruginosa is the opportunistic pathogen mostly implicated in folliculitis and acute otitis externa in pools and hot tubs. Nevertheless, infection risks remain poorly quantified. This paper reviews disease aetiologies and bacterial skin colonization science to advance dose-response theory development. Three model forms are identified for predicting disease likelihood from pathogen density. Two are based on Furumoto & Mickey's exponential 'single-hit' model and predict infection likelihood and severity (lesions/m2), respectively. 'Third-generation', mechanistic, dose-response algorithm development is additionally scoped. The proposed formulation integrates dispersion, epidermal interaction, and follicle invasion. The review also details uncertainties needing consideration which pertain to water quality, outbreaks, exposure time, infection sites, biofilms, cerumen, environmental factors (e.g. skin saturation, hydrodynamics), and whether P. aeruginosa is endogenous or exogenous. The review's findings are used to propose a conceptual infection model and identify research priorities including pool dose-response modelling, epidermis ecology and infection likelihood-based hygiene management.

The question of pathogen quantification in disinfected graywater

“…We found higher average quantities of these opportunistic bacteria in almost all tested samples in comparison with the enteric bacteria, as also reported by Zimmerman et al (2014). However, the infective dosages of P. aeruginosa and S. aureus (based on studies of oral intake or dermal exposure by healthy volunteers) are high, ranging from 10 4 to 10 8 for P. aeruginosa and 10 3 to 10 5 for S. aureus (Leggett et al, 2012;Roser et al, 2014;Rusin et al, 1997;Schmid-Hempel and Frank, 2007). On average these quantities were not found in the TGW or disinfected TGW.…”

“…According to our culturedependent data (Fig. 2), on average, both chlorine and UV were able to effectively inactivate these bacteria to below these levels (FDA, 2013;Leggett et al, 2012;Rusin et al, 1997;Roser et al, 2014;Schmid-Hempel and Frank, 2007). Interestingly, chlorine disinfection was more efficient than UV (Fig.…”

“…This is a complex issue as infective dose varies between people, type of contact (e.g. aerosols vs. ingestion), and specific pathogen properties (Leggett et al, 2012;Roser et al, 2014;Rusin et al, 1997;Schmid-Hempel and Frank, 2007). A complete inactivation of pathogens would be ideal but impractical.…”

Public health implications of Acanthamoeba and multiple potential opportunistic pathogens in roof-harvested rainwater tanks

“…P. aeruginosa was previously detected in 13% of rainwater samples (n ¼72) with concentrations up to 2 Â 10 3 gene copies per L of water (Ahmed et al, 2014), which is a lower prevalence and concentration compared to that reported in this study (9.6 Â 10 5 gene copies per L). P. aeruginosa is the most common opportunistic pathogen associated with infections acquired from recreational pools, hot tubs, and whirlpools, particularly due to folliculitis and acute otitis externa (Mena and Gerba, 2009;Roser et al, 2014). In the current study, rainwater was commonly used in pools, which could serve as an exposure route for this opportunistic pathogen.…”

Microbial Dose Response Modeling: Past, Present, and Future

“…• Pathogen survival in the upper GI tract • Establishment in the gut and attachment and take up by epithelium • Escape from phagosomes and transfer to phagocytes • Trans-placental transfer • Growth in fetus More recently, Roser et al 98 have developed a conceptual key events framework to the assessment of ear infections caused by Pseudomonas aeruginosa. The events identified in this case were:…”