Free-living amoebae: Biological by-passes in water treatment

Loret, Jean-François; Greub, Gilbert

doi:10.1016/j.ijheh.2010.03.004

Cited by 101 publications

(88 citation statements)

References 55 publications

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“…Acanthamoeba is a Trojan horse for microorganisms such as Escherichia coli O157, Legionella pneumophila, Coxiella burnetii, Helicobacter pylori, Chlamydophila pneumoniae, Vibrio cholerae, Listeria monocytogenes, Campylobacter jejuni, Mycobacterium leprae and Pseudomonas aeruginosa (Axelsson-Olsson et al 2005;Greub and Raoult 2004;Winiecka-Krusnell and Linder 2001). Prevalence of Acanthamoeba is correlated with the amount of organic matter present in the water, and its frequency is high in sediments and biofilms, which constitute ecological niches where they can feed on bacteria (Loret and Greub 2010). Two developmental stages of Acanthamoeba species can be found in their life cycle including a trophozoite stage that is vegetative and active with a size of about 13-23 lm, and a resistant cyst with a diameter about 13-23 lm (Siddiqui and Khan 2012).…”

Section: Introductionmentioning

confidence: 99%

Isolation of Acanthamoeba spp. from different water sources in Isfahan, central Iran, 2014

et al. 2016

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Acanthamoeba spp. are free-living amoeba found in a wide variety of natural habitats. The high percentage of the presence of Acanthamoeba in different environmental sources represents a sanitary risk for public health, especially immunocompromised patients and contact lens wearers. Acanthamoeba can cause granulomatous amoebic encephalitis, otitis, lung lesions, and skin infections in individuals with immune deficiencies. In the present study, the status of contamination of water sources in Isfahan, central Iran is analyzed through parasitological method. Totally 93 samples were utilized consisting of 59 samples of tap water and 34 samples of environmental water collected from Isfahan in May and June 2014. After filtering, cultivation was done in non-nutrient agar medium, and then the cultured media were kept at 25-30°C. The samples were analyzed based on the morphological criteria. Acanthamoeba spp. were found in 25 (73.53 %) out of 34 environmental water samples and 17 (28.8 %) out of 59 tap water. Generally, Acanthamoeba spp. were found in 42 (45.16 %) of the samples. The results of the present study showed that the water contamination with Acanthamoeba spp. in different regions of Isfahan can be a potential infection source for at high risk people. It could be suggested that public education and precaution are quiet necessary.

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Section: Introductionmentioning

confidence: 99%

Isolation of Acanthamoeba spp. from different water sources in Isfahan, central Iran, 2014

et al. 2016

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“…Intracellular L. pneumophila is more resistant to biocides (3,4,14). Consequently, free-living amoebae, such as Acanthamoeba, have been recently described as important targets in water treatment (19,30). Common biocides used in water treatment (i.e., chlorine, monochloramine, and chlorine dioxide) were assessed against pathogenic protozoa such as Giardia, Cryptosporidium, and to a lesser extent Entamoeba histolytica (20).…”

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confidence: 99%

Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments

Mogoa

Bodet

Morel

et al. 2011

Appl Environ Microbiol

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Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii.

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“…The samples were collected over different days for a total in a month/season. Along the treatment plant, samples (500 mL each) were collected from influent (16), bioreactor feed (20), anaerobic zone of the bioreactor (16), anoxic zone of the bioreactor (16), the two aerators (32), bioreactor effluent (16), bioreactor final effluent (11), and the maturation ponds (45).…”

Section: Sample Collectionmentioning

confidence: 99%

Comparative Study of Three Two-Stage Hybrid Ecological Wastewater Treatment Systems for Producing High Nutrient, Reclaimed Water for Irrigation Reuse in Developing Countries

2015

Water Treatment in Developed and Developing Nations

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Free-living amoebae pose a potential health risk in water systems as they may be pathogenic and harbor potential pathogenic bacteria known as amoebae resistant bacteria. Free-living amoebae were observed in 150 (87.2%) of the environmental water samples. In particular, Acanthamoeba sp. was identified in 22 (12.8%) using amoebal enrichment and confirmed by molecular analysis. FLA were isolated in all 8 stages of the wastewater treatment plant using the amoebal enrichment technique. A total of 16 (9.3%) samples were positive for FLA from influent, 20 (11.6%) from bioreactor feed, 16 (9.3%) from anaerobic zone, 16 (9.3%) from anoxic zone, 32 (18.6%) from aerators, 16 (9.3%) from bioreactor effluent, 11 (6.4%) from bioreactor final effluent, and 45 (26.2%) from maturation pond. This study provides baseline information on the occurrence of amoebae in wastewater treatment plant. This has health implications on receiving water bodies as some FLA are pathogenic and are also involved in the transmission and dissemination of pathogenic bacteria.

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Free-living amoebae: Biological by-passes in water treatment

Cited by 101 publications

References 55 publications

Isolation of Acanthamoeba spp. from different water sources in Isfahan, central Iran, 2014

Isolation of Acanthamoeba spp. from different water sources in Isfahan, central Iran, 2014

Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments

Comparative Study of Three Two-Stage Hybrid Ecological Wastewater Treatment Systems for Producing High Nutrient, Reclaimed Water for Irrigation Reuse in Developing Countries

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