Pathogens in Environmental Biofilms

Keevil, C. W.

doi:10.1002/0471263397.env202

Cited by 21 publications

(32 citation statements)

References 125 publications

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“…It has also been shown that bacteria attached to surfaces show greater resistance to disinfection (15,19,20,36). Biofilms in distribution systems may provide a favorable condition for some bacteria, such as opportunistic pathogens (e.g., Legionella spp., Pseudomonas aeruginosa, and Mycobacterium avium), to colonize it and may harbor pathogens, such as Salmonella enterica serovar Typhimurium, which have entered the distribution system (1,5,18,28). It has been shown in lab-scale experiments that E. coli can survive in biofilters (24) and even multiply in the biofilm (17,34,40), which again raises the question of its suitability as a drinking water quality indicator.…”

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confidence: 99%

Detection of Escherichia coli in Biofilms from Pipe Samples and Coupons in Drinking Water Distribution Networks

Juhna

Birzniece

Larsson

et al. 2007

Appl Environ Microbiol

103

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Fluorescence in situ hybridization (FISH) was used for direct detection of Escherichia coli on pipe surfaces and coupons in drinking water distribution networks. Old cast iron main pipes were removed from water distribution networks in France, England, Portugal, and Latvia, and E. coli was analyzed in the biofilm. In addition, 44 flat coupons made of cast iron, polyvinyl chloride, or stainless steel were placed into and continuously exposed to water on 15 locations of 6 distribution networks in France and Latvia and examined after 1 to 6 months exposure to the drinking water. In order to increase the signal intensity, a peptide nucleic acid (PNA) 15-mer probe was used in the FISH screening for the presence or absence of E. coli on the surface of pipes and coupons, thus reducing occasional problems of autofluorescence and low fluorescence of the labeled bacteria. For comparison, cells were removed from the surfaces and examined with culture-based or enzymatic (detection of ␤-D-glucuronidase) methods. An additional verification was made by using PCR. Culture method indicated presence of E. coli in one of five pipes, whereas all pipes were positive with the FISH methods. E. coli was detected in 56% of the coupons using PNA FISH, but no E. coli was detected using culture or enzymatic methods. PCR analyses confirmed the presence of E. coli in samples that were negative according to culture-based and enzymatic methods. The viability of E. coli cells in the samples was demonstrated by the cell elongation after resuscitation in low-nutrient medium supplemented with pipemidic acid, suggesting that the cells were present in an active but nonculturable state, unable to grow on agar media. E. coli contributed to ca. 0.001 to 0.1% of the total bacterial number in the samples. The presence and number of E. coli did not correlate with any of physical and/or chemical characteristic of the drinking water (e.g., temperature, chlorine, or biodegradable organic matter concentration). We show here that E. coli is present in the biofilms of drinking water networks in Europe. Some of the cells are metabolically active but are often not detected due to limitations of traditionally used culture-based methods, indicating that biofilm should be considered as a reservoir that must be investigated further in order to evaluate the risk for human health.The drinking water supplier has to provide the consumer potable water of a quality identical to that leaving the treatment plant. However, it has been well documented that water that reaches the consumer's tap is often of worse microbiological quality than that which left the plant (29). Therefore, the analyses used for monitoring the hygiene of potable water must be rapid to perform and able to detect the major microbial groups of concern. Escherichia coli is still used as the principle indicator for drinking water pollution monitoring (39) and is even considered a superior indicator (11), since enterotoxic and enterohemorrhagic forms are one of the major causes of water-related outbreaks (29...

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confidence: 99%

Detection of Escherichia coli in Biofilms from Pipe Samples and Coupons in Drinking Water Distribution Networks

Juhna

Birzniece

Larsson

et al. 2007

Appl Environ Microbiol

103

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“…The inclusion and persistence of naturally occurring L. pneumophila at cold-water temperatures and multiplication of these bacteria at warm-water temperatures in biofilms of autochthonous water bacteria have been observed on various plumbing materials including ethylene-propylene, PE-X, non-plasticized PVC and copper (Keevil 2003;Gião et al 2009a, b). Seeding experiments indicated that L. pneumophila could become integrated in pre-existing biofilms and survive or even multiply in these biofilms, depending on the environmental conditions (Armon et al 1997;Långmark et al 2005;Lehtola et al 2007;Benölken et al 2010).…”

Section: Pneumophila and P Aeruginosa Incorporated Into Drinking mentioning

confidence: 99%

“…Certain types of plastic and elastomeric materials can promote biofilm formation due to the release of biodegradable compounds such as monomers or additives like plasticizers, anti-oxidants, providing favorable nutrient conditions for microorganisms (Schoenen and Schoeler 1983;van der Wende et al 1989;Keevil 2003;Anonymous 2007). It has been estimated that about 95% of all microbial cells present in drinking water distribution systems exist as biofilms on pipe surfaces, only 5% occur in the water phase .…”

Section: Biofilms In Drinking Water Systemsmentioning

confidence: 99%

“…Drinking water biofilms are formed predominantly by microorganisms of the autochthonous aquatic microflora without any relevance to human health. However, biofilms have the potential to harbor microbial pathogens which can harm human health, especially in immunocompromised persons (Keevil 2003). Once integrated in a drinking water biofilm, these organisms can tolerate external stresses such as the action of disinfectants much better and can thus persist and possibly multiply inside the biofilm.…”

Section: Biofilms In Drinking Water Systemsmentioning

confidence: 99%

“…If starved drinking water bacteria meet materials which release nutrients, they settle, form biofilms and grow Keevil 2003;. Usual suspect materials in such cases are synthetic polymers which are not approved for use in drinking water.…”

Section: The Role Of Materialsmentioning

confidence: 99%

See 2 more Smart Citations

Microbial Growth in Drinking-Water Supplies: Problems, Causes, Control and Research Needs

Kooij¹,

Wielen²

2013

wio

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Understanding microbial ecology to improve management of drinking water distribution systems

et al. 2018

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Microorganisms in drinking water distribution systems (DWDS), and in particular the microbial communities that form biofilms on infrastructure surfaces, drive critical processes impacting water quality. This paper reviews knowledge, research approaches, and monitoring methods to consolidate understanding of the microbial ecology of DWDS. The review highlights how microbial characteristics and subsequent behavior can be broadly classified as common or complex. Common behavior relates to the ubiquitous and continual development of biofilms, consistent core communities, and mediated material accumulation. In contrast, the complex aspect relates to the shape, structure, and composition of the microbiome, defined by site‐specific properties such as supplied source water, pipe material, and hydraulic regimes. It is shown how the latest microbial tools and techniques can be applied to increase our understanding of DWDS ecology and how water utilities are starting to use this knowledge. This is not because of regulatory requirements, but in recognition that they provide valuable information facilitating proactive management and operation benefits to these critical yet aging systems, protecting water quality and public health in the process. This article is categorized under: Engineering Water > Sustainable Engineering of Water Water and Life > Nature of Freshwater Ecosystems

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Pathogens in Environmental Biofilms

Abstract: Biofilm Structure Autochthonous Biofilm Microflora Autochthonous Biofilm Pathogens Allochthonous Biofilm Pathogens Biofilm Safe Haven

Cited by 21 publications

References 125 publications

Detection of Escherichia coli in Biofilms from Pipe Samples and Coupons in Drinking Water Distribution Networks

Detection of Escherichia coli in Biofilms from Pipe Samples and Coupons in Drinking Water Distribution Networks

Microbial Growth in Drinking-Water Supplies: Problems, Causes, Control and Research Needs

Understanding microbial ecology to improve management of drinking water distribution systems

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