Chapter 118 : Risk of Legionella in the Spa Industry: Inadequacy of Current Legislation Covering Thermal Waters used for Medicinal Purposes

Abstract:

This chapter investigates the overall Legionella colonization of thermal water and cold and hot water of particular hotels, including the detailed identification and typing of species and serogroups. The aim was also to evaluate the risk of particular hydrotherapy procedures, to identify the source of the Philadelphia strain in the spa complex, and to propose corrective actions to minimize the risk of future Legionella infections. Permanent chlorine dioxide disinfection was recommended for the hot water systems of the two hotels. A dilemma caused by the legislation has arisen as to how to treat the thermal water and its distribution system. Oxidizing biocides and ionizers are not permitted by law. Regular thermal disinfection is recommended, but its application is often unfeasible for the rapid settling of mineral deposits and scale, which usually clog pipes and valves. The bath equipment (mostly very sophisticated) contained many different kinds of tubing and hoses and air and water jets that were almost all colonized with biofilms harboring Legionella. Thermal and hot water distribution systems and hydrotherapy procedures present the sources, while aerosol inhalation and drinking water appear to be the transmission.