Pseudomonas Dermatitis/Folliculitis Associated With Pools and Hot Tubs — Colorado and Maine, 1999-2000

Morbidity and Mortality Weekly Report, Dec 8, 2000

Reported by: G Beckett, MPH, D Williams, G Giberson, KF Gensheimer, MD; State Epidemiologist, Maine Bur of Health. K Gershman, MD, P Shillam, MSPH, RE Hoffman, MD, State Epidemiologist, Colorado Dept of Public Health and Environment; R Merry, H Savalox, L Fawcett, Eagle County Environmental Health Div, Eagle, Colorado. Hospital Infections Program, and Div of Parasitic Diseases, National Center for Infectious Diseases; Div of Applied Public Health Training, Epidemiology Program Office; and EIS officers, CDC.

Editorial Note: Pseudomonas aeruginosa, a gram negative rod, is ubiquitous and can cause various mild to severe symptoms [1]. Pseudomonas dermatitis and otitis externa outbreaks associated with swimming pool and hot tub use are well described [2,3]; at least 75 cases during six outbreaks occurred during 1997-1998 [4]. Dermatitis outbreaks usually occur as a result of low water disinfectant levels [2,3], a condition that also increases the risk for transmission of other chlorine-sensitive pathogens (e.g., Escherichia coli 0157:H7 and Shigelia sonnei) that may cause severe health consequences.

In this report, factors that may have resulted in inadequate disinfectant levels included the use of an offsite contractor who could monitor and alert pool staff to low free chlorine or pH levels but could not change free chlorine or pH levels, and hotel employees with a minimal understanding of the offsite monitoring and alert system, pool maintenance, and the link between inadequate water disinfection and disease transmission. In addition, pools and hot tubs were not monitored routinely onsite to adjust to high bather loads that can lower free chlorine levels. In Maine, cyanuric acid was added to the indoor pool and hot tub. However, cyanuric acid, which is used to reduce chlorine loss as a result of ultraviolet light exposure, is not recommended for indoor pools or hot tubs [5,6] and is prohibited in two states [7]; adding this chemical reduces the antimicrobial capacity of free chlorine [8].

To reduce the risk for Pseudomonas dermatitis and the transmission of other waterborne pathogens, pool and hot tub operators should 1) adhere to pool and hot tub recommendations and regulatory requirements for pH and disinfectant levels (6,9,10); 2) have a thorough knowledge of basic aquatic facility operation; 3) provide training for pool staff on system capabilities, maintenance, and emergency alert procedures of remote monitoring systems; 4) closely monitor pool and hot tub free chlorine measurements during periods of heavy bather loading; 5) monitor hot tub disinfectant levels closely because the higher temperatures maintained serve to dissipate chlorine rapidly; and 6) understand appropriate use and effects of cyanurates on disinfection and testing. In addition, remote-monitoring companies should be timely in notifying swimming-facility staff about low disinfectant levels. Swimmers should be educated about the potential for waterborne disease transmission in pools and hot tubs, which could increase advo cacy for improved maintenance and monitoring by pool operators.