Effects of metals on Legionella pneumophila growth in drinking water plumbing systems

States, Stanley; Conley, L F; Ceraso, M; Stephenson, Tom; Wolford, R S; Wadowsky, Robert M.; McNamara, A M; Yee, Robert B.

doi:10.1128/aem.50.5.1149-1154.1985

Cited by 64 publications

(38 citation statements)

References 38 publications

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“…Additionally, among the four metals examined, only iron concentration significantly correlated with Legionella contamination. This promotive activity of iron agrees well with the findings of States et al. (1985), who showed that a high concentration of iron (>1·0 mg l −1 ) in hot water tanks enhanced Legionella growth 2‐ to 100‐fold.…”

Section: Discussionsupporting

confidence: 91%

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Edagawa

Kimura

Doi

et al. 2008

Journal of Applied Microbiology

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Aims: To investigate the prevalence of culturable and nonculturable Legionella species in hot water systems of public buildings in Japan and assess the risk factors associated with Legionella contamination in hot water systems. Methods and Results: Legionella species were detected by conventional culture and molecular methods in 130 water samples collected from 40 buildings. A total of 26 (20·0%) water samples from 17 (42·5%) buildings were positive by culture, qualitative PCR or both methods: Legionella pneumophila and Leg. anisa were detected in four samples by a culture method, whereas 23 samples were positive by qualitative PCR, with the presence of various Legionella species confirmed by sequencing. Of these 23 samples, bacterial counts were quantifiable in 21 by real‐time PCR (from 1·7 × 105 to 2·6 × 1011 cells per litre). Phylogenetic analysis of amplified partial 16S rRNA gene showed close relations to various species of Legionella, including Leg. anisa and Leg. micdadei, all of which have been associated with respiratory diseases or increased antibody titres in human sera. Assessment of risk factors showed that turbidity, free chlorine concentration, iron concentration and heterotrophic plate count (HPC) were significantly associated with Legionella contamination (P < 0·05). Conclusions: Contamination of hot water systems of public buildings with culturable and nonculturable Legionella species may be a potential risk factor for Legionella infection in Japan. Adequate levels of chlorine, low levels of iron and HPC are important maintenance measures in the reduction of Legionella contamination in hot water systems. Significance and Impact of the Study: More than 40% of hot water systems in the Japanese public buildings examined were contaminated by not only culturable Leg. pneumophila and Leg. anisa but also by nonculturable pathogenic species. To our knowledge, this is the first report of both culturable and nonculturable Legionella contamination in hot water systems of public buildings in Japan.

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Section: Discussionsupporting

confidence: 91%

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Edagawa

Kimura

Doi

et al. 2008

Journal of Applied Microbiology

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“…The concentration of metals in hot-water tanks was shown previously to influence the multiplication of L. pneumophila. Low concentrations of iron and zinc, for example, enhanced the growth of L. pneumophila inoculated into hot-water tank samples and in tap water supplemented with other metals (28). The high levels of sulfide and/or the high pH at sites 1F and 1H may have contributed to the inhibition of growth or survival of Legionella spp.…”

Section: Discussionmentioning

confidence: 99%

Distribution of Legionella spp. in hydrothermal areas in continental Portugal and the island of São Miguel, Azores

Veríssimo

Marrão

Silva

et al. 1991

Appl Environ Microbiol

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Nineteen aquatic environment sites from three hydrothermal areas on continental Portugal and one area on the island of Sao Miguel, Azores, were examined for the recovery of Legionella spp. Physicochemical and bacteriological parameters were also determined for each site. Water temperatures varied between 22 and 67.5°C, although the majority had temperatures above 40°C; the pH varied between 5.5 and 9.2. The number of Legionella spp. recovered varied between 5.0 x 102 and 2.3 x 106 CFU/liter. A total of 288 isolates from 14 sites were identified by indirect immunofluorescence assay. The majority of the isolates belonged to Legionella pneumophila (74.3%), of which most belong to serogroup 1, but the relative proportion of L. pneumophila serogroups varied considerably. L. pneumophila serogroup 1 constituted 96.2% of the isolates in area 2 from central Portugal, but no isolates of this serogroup were recovered from Sao Miguel, where serogroup 6 strains were the predominant isolates. Ninety-six percent of the L. pneumophila serogroup 1 isolates belonged to monoclonal antibody subgroups OLDA and Bellingham. Other species identified were L. bozemanii serogroup 2, L. dumoffii, L. micdadei, L. moravica, L. oakridgensis, L. sainticrucis, and L. sainthelensi. Two undescribed species, which react by indirect immunofluorescence assay to antisera to "L. londoniensis" and "L. nautarum" and a group of isolates with strong cross-reaction to L. cincinnatiensisiL. sainticrucisiL. longbeachae by indirect immunofluorescence assay were also recovered. The latter were the only isolates recovered from area 3, in east central Portugal, over a period of 1 year.

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“…Iron limitation leads to greatly reduced virulence of Legionella (James et al, 1995). Metal plumbing components and associated corrosion products are important factors in providing iron and other metals that support the survival and growth of L. pneumophila in plumbing systems and may also be important in related habitats, such as cooling towers and air-conditioning systems (States et al, 1985).…”

Section: Environmental Sources Of Legionellosismentioning

confidence: 99%

Legionella: from environmental habitats to disease pathology, detection and control

Atlas

1999

Environmental Microbiology

213

148

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Studies on Legionella show a continuum from environment to human disease. Legionellosis is caused by Legionella species acquired from environmental sources, principally water sources such as cooling towers, where Legionella grows intracellularly in protozoa within biofilms. Aquatic biofilms, which are widespread not only in nature, but also in medical and dental devices, are ecological niches in which Legionella survives and proliferates and the ultimate sources to which outbreaks of legionellosis can be traced. Invasion and intracellular replication of L. pneumophila within protozoa in the environment play a major role in the transmission of Legionnaires' disease. Protozoa provide the habitats for the environmental survival and reproduction of Legionella species. L. pneumophila proliferates intracellularly in various species of protozoa within vacuoles studded with ribosomes, as it also does within macrophages. Growth within protozoa enhances the environmental survival capability and the pathogenicity (virulence) of Legionella. The growth requirements of Legionella, the ability of Legionella to enter a viable non‐culturable state, the association of Legionella with protozoa and the occurrence of Legionella within biofilms complicates the detection of Legionella and epidemiological investigations of legionellosis. Polymerase chain reaction (PCR) methods have been developed for the molecular detection of Legionella and used in environmental and epidemiological studies. Various physical and chemical disinfection methods have been developed to eliminate Legionella from environmental sources, but gaining control of Legionella in environmental waters, where they are protected from disinfection by growing within protozoa and biofilms, remains a challenge, and one that must be overcome in order to eliminate sporadic outbreaks of legionellosis.

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Effects of metals on Legionella pneumophila growth in drinking water plumbing systems

Cited by 64 publications

References 38 publications

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Distribution of Legionella spp. in hydrothermal areas in continental Portugal and the island of São Miguel, Azores

Legionella: from environmental habitats to disease pathology, detection and control

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