• OPs in shower systems should be measured and managed integrally for biosafety. • Multi-phases should be considered, e.g., water, biofilms, and aerosols. • Multi-components should be considered, e.g., shower hoses, heads, and pipes. • Multi-OPs should be considered, e.g., Legionella, Mycobacterium, Pseudomonas . Shower systems are common in buildings, and their diverse components and usage patterns create ideal conditions for the growth of opportunistic pathogens (OPs). Legionella spp., Mycobacterium spp., and Pseudomonas aeruginosa can be transmitted through aerosols during showers, leading to respiratory and pulmonary infections, particularly in immunocompromised individuals, raising significant concerns. This article reviews the prevalence of OPs in shower systems, focusing on methods for sampling and analyzing water, biofilms, and aerosols, and assessing their applicability. While many studies examine specific components or phases of shower systems, an integral assessment is lacking. The article also explores key factors influencing OPs colonization, noting that control measures may not always be fully effective. For instance, disinfectants may have opposing effects on Legionella spp. and Mycobacterium spp., and the impact of metal ions on OPs can vary depending on water chemistry, usage duration, and patterns. Additionally, while raising temperature may control OPs in hot-water pipes, its effectiveness on other parts of the shower system, such shower hoses, showerheads, and cold-water pipes, remains unclear. This review points out that to effectively control the overall microbial risks in shower systems, it may be necessary to comprehensively apply a variety of control measures. Meanwhile, the article advocates conducting research on multi-components, multi-phases, and multi-OPs in shower systems, clarifying the distribution of microbial risks in shower systems, and then implementing targeted risk management strategies.
Ren et al. (Sun,) studied this question.