Influence of temperature and plumbing material selection on biofilm formation and growth of Legionella pneumophila in a model potable water system containing complex microbial flora

Rogers, J; Dowsett, A. B.; Dennis, P. J.; Lee, J V; Keevil, C. W.

doi:10.1128/aem.60.5.1585-1592.1994

Cited by 240 publications

(120 citation statements)

References 23 publications

(17 reference statements)

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“…There was also little impact of the material on the numbers of cultivable attached bacteria. In an earlier study, Rogers et al (1994) highlighted the importance of this parameter by showing that numbers of Legionella pneumophila ranged from 0 CFU cm )2 for copper to 2132 CFU cm )2 for PVC at 20°C and under shear stress.…”

Section: Discussionmentioning

confidence: 99%

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Adhesion of water stressed Helicobacter pylori to abiotic surfaces

et al. 2006

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Aim: The main aim of this work was to study and compare the adhesion of water exposed Helicobacter pylori to six different substrata and correlate any changes in morphology, physiology, ability to form aggregates and cultivability when in the planktonic or in the sessile phase. Methods and Results: The number of total cells adhered for different water exposure times and modifications in the cell shape were evaluated using epifluorescence and scanning electron microscopy, and physiology assessed using Syto9 and propidium iodide (PI) cellular uptake. All abiotic surfaces were rapidly colonized by H. pylori, and colonization appeared to reach a steady state after 96 h with levels ranging from 2·3 × 106 to 3·6 × 106 total cells cm−2. Cell morphology was largely dependent on the support material, with spiral bacteria, associated with the infectious form of H. pylori, subsisting in a higher percentage on nonpolymeric substrata. Also, sessile bacteria were generally able to retain the spiral shape for longer when compared with planktonic bacteria, which became coccoid more quickly. The formation of large aggregates, which may act as a protection mechanism against the negative impact of the stressful external environmental conditions, was mostly observed on the surface of copper coupons. However, Syto9 and PI staining indicates that most of H. pylori attached to copper or SS304 have a compromised cell membrane after only 48 h. Cultivability methods were only able to detect the bacteria up to the 2 h exposure‐time and at very low levels (up to 500 CFU cm−2). Conclusions: The fact that the pathogen is able to adhere, retain the spiral morphology for longer and form large aggregates when attached to different plumbing materials appeared to point to pipe materials in general, and copper plumbing in particular, as a possible reservoir of virulent H. pylori in water distribution systems. However, the Syto9/PI staining results and cultivability methods indicate that the attached H. pylori cells quickly enter in a nonviable physiological state. Significance and Impact of the Study: This represents the first study of H. pylori behaviour in water‐exposed abiotic surfaces. It suggests that co‐aggregation with the autochthonous heterotrophic consortia present in water is necessary for a longer survival of the pathogen in biofilms associated to drinking water systems.

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Section: Discussionmentioning

confidence: 99%

“…Substratum material is one of the factors affecting the growth of biofilms. Abiotic surfaces have been shown to not only influence the attachment of total bacteria (Pedersen 1990;Kerr et al 1999), but also the attachment of particular pathogens (Rogers et al 1994).…”

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confidence: 99%

Adhesion of water stressed Helicobacter pylori to abiotic surfaces

et al. 2006

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“…Also the material of the piping system has been shown to in£uence the occurrence of high bacterial concentrations. In this respect the use of copper as plumbing material may help to minimize the risk of Legionnaires' disease whereas plastic materials support high numbers of L. pneumophila [15].…”

Section: Natural and Man-made Habitatsmentioning

confidence: 99%

Legionella pneumophila: an aquatic microbe goes astray

Steinert

2002

FEMS Microbiology Reviews

117

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Legionella pneumophila is naturally found in fresh water were the bacteria parasitize within protozoa. It also survives planctonically in water or biofilms. Upon aerosol formation via man-made water systems, L. pneumophila can enter the human lung and cause a severe form of pneumonia, called Legionnaires' disease. The pathogenesis of Legionnaires' disease is largely due to the ability of L. pneumophila to invade and grow within macrophages. An important characteristic of the intracellular survival strategy is the replication within the host vacuole that does not fuse with endosomes or lysosomes. In recent times a great number of bacterial virulence factors which affect growth of L. pneumophila in both macrophages and protozoa have been identified. The ongoing Legionella genome project and the use of genetically tractable surrogate hosts are expected to significantly contribute to the understanding of bacterium-host interactions and the regulation of virulence traits during the infection cycle. Since person-to-person transmission of legionellosis has never been observed, the measures for disease prevention have concentrated on eliminating the pathogen from water supplies. In this respect detection and analysis of Legionella in complex environmental consortia become increasingly important. With the availability of new molecular tools this area of applied research has gained new momentum.

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“…Bio®lms, which are widespread not only in nature but also in medical and dental devices, have been identi®ed as ecological niches in which L. pneumophila not only survives but proliferates and lies in wait for susceptible hosts (Barbeau et al, 1998). In water piping systems, L. pneumophila has been found to be most abundant in bio®lms on plastics at 408C, where it accounted for up to 50% of the total bio®lm¯ora; in contrast, pipes with copper surfaces were inhibitory to total biofouling and included only low numbers of L. pneumophila (Rogers et al, 1994). Iron limitation leads to greatly reduced virulence of Legionella (James et al, 1995).…”

Section: Environmental Sources Of Legionellosismentioning

confidence: 99%

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

Atlas

1999

Environmental Microbiology

210

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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Influence of temperature and plumbing material selection on biofilm formation and growth of Legionella pneumophila in a model potable water system containing complex microbial flora

Cited by 240 publications

References 23 publications

Adhesion of water stressed Helicobacter pylori to abiotic surfaces

Adhesion of water stressed Helicobacter pylori to abiotic surfaces

Legionella pneumophila: an aquatic microbe goes astray

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

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