Microbiology of recreational and therapeutic whirlpools

Over half of the reported outbreaks of whirlpool‐associated dermatitis and folliculitis have been caused by Pseudomonas aeruginosa, serotype 011. Illness caused by Staphylococcus aureus, Legionella pneumophila, Mycobacterium, Streptococci, and Acanthamoeba have been infrequently reported. The presence of microorganisms in water is not the only factor involved in infection transmission. Other factors in disease may be individual host susceptibility, immersion time, bather load, gender, and use of clothing. A bather's risk for P. aeruginosa dermatitis or folliculitis appears to depend on immersion in water colonized by P. aeruginosa, skin hydration with altered skin flora, and toxic reactions to extracellular enzymes or exotoxins produced by P. aeruginosa. Outbreaks of illness appear to be directly related to inadequate operational and maintenance procedures. Chemical and physical parameters should be routinely monitored. Microbiologic sampling of whirlpool water is not advised except in outbreak investigations.