Legionella Contamination of a Preoperational Treatment Plant

Abstract

A study of the distribution of Legionella in a newly constructed water treatment facility found Legionella pneumophila (serogroup 1) in both hot‐ and cold‐water lines. The contamination was monitored by bacterial enumeration of samples collected from various sites in the building and from disassembled plumbing fixtures. Repeated flushing and hyperchlorination were inadequate as decontamination procedures, presumably because the organism had colonized interior spaces of valves and associated parts that are inaccessible to chlorine and unaffected by flushing.

WidespreadLegionella pneumophilacontamination of dental stations in a dental school without apparent human infection

“…However, it was not possible to demonstrate the presence of the organisms in the boosted mains supply during the course of this investigation and the apparent elimination of the organism from the plumbing system for 20 weeks after chlorination was not indicative of low level seeding from the mains supply. Although the role of the booster pumps as an amplification site could not be demonstrated, the temperature profile of the water was within the range which permits legionella colonization (Voss et al 1986).…”

Protocol for sampling environmental sites for legionellae

“…Although legionellae were not isolated from water before it entered either hospital property, periodic sampling would be needed to rule out intermittent entry of legionellae from outside sources such as municipal water reservoirs. Legionellae have been isolated from water treatment plants (17,18).…”

“…The first category (A), potable water outside and on the boundary of hospital property, is included to document external sources of municipal water that contain legionellae and may seed the water and plumbing systems of the building. The reports of other investigators such as Voss et al (17,18) have indicated that municipal water treatment plants harbor legionellae and emphasize the need to identify external contamination sources. The second category (B), the general potable water system for a hospital or facility, includes sites that can be very important for disease transmission.…”

Overview and comparison of Legionella regulations worldwide

“…Since 1985, studies have shown that Legionella is present in all segments of community water supplies, including treatment facilities. 5,6,7,8 The 1985 Legionella Criteria Document states that Legionella is widely distributed in the natural environment worldwide. 9 Legionella exhibits the ability to survive in an extremely wide range of conditions in natural and man-made aquatic habitats.…”