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Nisar MA, Ros KE, Brown MH, Bentham R, Best G, Xi J, Hinds J, Whiley H. Stagnation arising through intermittent usage is associated with increased viable but non culturable Legionella and amoeba hosts in a hospital water system. Front Cell Infect Microbiol 2023; 13:1190631. [PMID: 37351181 PMCID: PMC10282743 DOI: 10.3389/fcimb.2023.1190631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/18/2023] [Indexed: 06/24/2023] Open
Abstract
Hospital water systems are a significant source of Legionella, resulting in the potentially fatal Legionnaires' disease. One of the biggest challenges for Legionella management within these systems is that under unfavorable conditions Legionella transforms itself into a viable but non culturable (VBNC) state that cannot be detected using the standard methods. This study used a novel method (flow cytometry-cell sorting and qPCR [VFC+qPCR] assay) concurrently with the standard detection methods to examine the effect of temporary water stagnation, on Legionella spp. and microbial communities present in a hospital water system. Water samples were also analyzed for amoebae using culture and Vermamoeba vermiformis and Acanthamoeba specific qPCR. The water temperature, number and duration of water flow events for the hand basins and showers sampled was measured using the Enware Smart Flow® monitoring system. qPCR analysis demonstrated that 21.8% samples were positive for Legionella spp., 21% for L. pneumophila, 40.9% for V. vermiformis and 4.2% for Acanthamoeba. All samples that were Legionella spp. positive using qPCR (22%) were also positive for VBNC Legionella spp.; however, only 2.5% of samples were positive for culturable Legionella spp. 18.1% of the samples were positive for free-living amoebae (FLA) using culture. All samples positive for Legionella spp. were also positive for FLA. Samples with a high heterotrophic plate count (HPC ≥ 5 × 103 CFU/L) were also significantly associated with high concentrations of Legionella spp. DNA, VBNC Legionella spp./L. pneumophila (p < 0.01) and V. vermiformis (p < 0.05). Temporary water stagnation arising through intermittent usage (< 2 hours of usage per month) significantly (p < 0.01) increased the amount of Legionella spp. DNA, VBNC Legionella spp./L. pneumophila, and V. vermiformis; however, it did not significantly impact the HPC load. In contrast to stagnation, no relationship was observed between the microbes and water temperature. In conclusion, Legionella spp. (DNA and VBNC) was associated with V. vermiformis, heterotrophic bacteria, and stagnation occurring through intermittent usage. This is the first study to monitor VBNC Legionella spp. within a hospital water system. The high percentage of false negative Legionella spp. results provided by the culture method supports the use of either qPCR or VFC+qPCR to monitor Legionella spp. contamination within hospital water systems.
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Affiliation(s)
- Muhammad Atif Nisar
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Kirstin E. Ros
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
- Australian Research Council Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Giles Best
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
- Flow Cytometry Facility, Flinders University, Bedford Park, SA, Australia
| | - James Xi
- Enware Australia Pty Ltd., Caringbah, NSW, Australia
| | - Jason Hinds
- Enware Australia Pty Ltd., Caringbah, NSW, Australia
| | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
- Australian Research Council Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, Australia
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Köstlbacher S, Collingro A, Halter T, Schulz F, Jungbluth SP, Horn M. Pangenomics reveals alternative environmental lifestyles among chlamydiae. Nat Commun 2021; 12:4021. [PMID: 34188040 PMCID: PMC8242063 DOI: 10.1038/s41467-021-24294-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/10/2021] [Indexed: 02/07/2023] Open
Abstract
Chlamydiae are highly successful strictly intracellular bacteria associated with diverse eukaryotic hosts. Here we analyzed metagenome-assembled genomes of the "Genomes from Earth's Microbiomes" initiative from diverse environmental samples, which almost double the known phylogenetic diversity of the phylum and facilitate a highly resolved view at the chlamydial pangenome. Chlamydiae are defined by a relatively large core genome indicative of an intracellular lifestyle, and a highly dynamic accessory genome of environmental lineages. We observe chlamydial lineages that encode enzymes of the reductive tricarboxylic acid cycle and for light-driven ATP synthesis. We show a widespread potential for anaerobic energy generation through pyruvate fermentation or the arginine deiminase pathway, and we add lineages capable of molecular hydrogen production. Genome-informed analysis of environmental distribution revealed lineage-specific niches and a high abundance of chlamydiae in some habitats. Together, our data provide an extended perspective of the variability of chlamydial biology and the ecology of this phylum of intracellular microbes.
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Affiliation(s)
- Stephan Köstlbacher
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Tamara Halter
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | | | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
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Shyrobokov V, Poniatovskyi V, Chobotar A, Sałamatin R. Applying of bacteria Cellulosimicrobium sp. for cultivation protozoa of genus Acanthamoeba. Ann Parasitol 2020; 66:61–67. [PMID: 32198996 DOI: 10.17420/ap6601.238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The aim of this study was identification features of cultivation representatives of genus Acanthamoeba isolated from bentonite using Cellulosimicrobium sp. as a bacteria-feeders. Identification of isolated bacteria was conducted by morphological, cultural and molecular-genetic methods. The cultivation of free-living „bentonite” amoeba on the lawn of Cellulosimicrobium sp. have gained significant advantages than using Escherichia coli as a bacteriafeeders was shown. “Bentonite” amoeba form crateroid plaques, which fit to the quantitative characteristic materials which contains amoeba, during deep co-cultivation Acanthamoeba sp. and Cellulosimicrobium sp. on 1% glucose meet-peptone agar.
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Affiliation(s)
- Volodymyr Shyrobokov
- Department of Microbiology, Virology and Immunology, Bogomolets National Medical University, Peremogy av. 34, 03056 Kyiv, Ukraine
| | - Vadym Poniatovskyi
- Department of Microbiology, Virology and Immunology, Bogomolets National Medical University, Peremogy av. 34, 03056 Kyiv, Ukraine
| | - Anastasiia Chobotar
- Department of Microbiology, Virology and Immunology, Bogomolets National Medical University, Peremogy av. 34, 03056 Kyiv, Ukraine
| | - Rusłan Sałamatin
- Department of General Biology and Parasitology, Medical University of Warsaw, Chałubińskiego 5, 02-004 Warsaw, Poland
- Department of Parasitology and Vector-Borne Diseases, National Institute of Public Health – National Institute of Hygiene, Chocimska 24, 00-791 Warsaw, Poland
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Okubo T, Matsushita M, Nakamura S, Matsuo J, Nagai H, Yamaguchi H. Acanthamoeba S13WT relies on its bacterial endosymbiont to backpack human pathogenic bacteria and resist Legionella infection on solid media. Environ Microbiol Rep 2018; 10:344-354. [PMID: 29611898 DOI: 10.1111/1758-2229.12645] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Soil-borne amoeba Acanthamoeba S13WT has an endosymbiotic relationship with an environmental Neochlamydia bacterial strain. However, regardless of extensive experiments in liquid media, the biological advantage of the symbiosis remained elusive. We therefore explored the role of the endosymbiont in predator-prey interactions on solid media. A mixed culture of the symbiotic or aposymbiotic amoebae and GFP-expressing Escherichia coli or Salmonella Enteritidis was spotted onto the centre of a LB or B-CYE agar plate preinoculated with a ring of mCherry-expressing Legionella pneumophila (Legionella 'wall'). The spread of the amoebae on the plate was assessed using a fluorescence imaging system or scanning electron microscopy. As a result, in contrast to the aposymbiotic amoebae, the symbiotic amoebae backpacked these GFP-expressing bacteria and formed flower-like fluorescence patterns in an anticlockwise direction. Other bacteria (Pseudomonas aeruginosa and Stenotrophomonas maltophilia), but not Staphylococcus aureus, were also backpacked by the symbiotic amoebae on LB agar, although lacked the movement to anticlockwise direction. Furthermore, in contrast to the aposymbiotic amoebae, the symbiotic amoebae backpacking the E. coli broke through the Legionella 'wall' on B-CYE agar plates. Thus, we concluded that Acanthamoeba S13WT required the Neochlamydia endosymbiont to backpack human pathogenic bacteria and resist Legionella infection on solid agar.
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Affiliation(s)
- Torahiko Okubo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Mizue Matsushita
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Shinji Nakamura
- Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Junji Matsuo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroki Nagai
- Department of Microbiology, Gifu University School of Medicine, Yanagido 1-1, Gifu, Gifu 501-1194, Japan
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan
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Dobrowsky PH, Khan S, Khan W. Resistance of Legionella and Acanthamoeba mauritaniensis to heat treatment as determined by relative and quantitative polymerase chain reactions. Environ Res 2017; 158:82-93. [PMID: 28609649 DOI: 10.1016/j.envres.2017.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/11/2017] [Accepted: 06/04/2017] [Indexed: 06/07/2023]
Abstract
Legionella and Acanthamoeba spp. persist in harvested rainwater pasteurized at high temperatures (> 72°C) and the interaction mechanisms exhibited between these organisms need to be elucidated. The resistance of two Legionella reference strains (Legionella pneumophila ATCC 33152 and Legionella longbeachae ATCC 33462), three environmental strains [Legionella longbeachae (env.), Legionella norrlandica (env.) and Legionella rowbothamii (env.)] and Acanthamoeba mauritaniensis ATCC 50676 to heat treatment (50-90°C) was determined by monitoring culturability and viability [ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR)]. The expression of metabolic and virulence genes of L. pneumophila ATCC 33152 (lolA, sidF, csrA) and L. longbeachae (env.) (lolA) in co-culture with A. mauritaniensis ATCC 50676 during heat treatment (50-90°C) was monitored using relative qPCR. While the culturability (CFU/mL) and viability (gene copies/mL) of the Legionella strains reduced significantly (p < 0.05) following heat treatment (60-90°C), L. longbeachae (env.) and L. pneumophila ATCC 33152 were culturable following heat treatment at 50-60°C. Metabolically active trophozoites and dormant cysts of A. mauritaniensis ATCC 50676 were detected at 50°C and 60-90°C, respectively. For L. pneumophila ATCC 33152, lolA expression remained constant, sidF expression increased and the expression of csrA decreased during co-culture with A. mauritaniensis ATCC 50676. For L. longbeachae (env.), while lolA was up-regulated at 50-70°C, expression was not detected at 80-90°C and in co-culture. In conclusion, while heat treatment may reduce the number of viable Legionella spp. in monoculture, results indicate that the presence of A. mauritaniensis increases the virulence of L. pneumophila during heat treatment. The virulence of Legionella spp. in co-culture with Acanthamoeba spp. should thus be monitored in water distribution systems where temperature (heat) is utilized for treatment.
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Affiliation(s)
- Penelope H Dobrowsky
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
| | - Sehaam Khan
- Faculty of Health and Applied Sciences, Namibia University of Science and Technology,13 Storch Street, Private Bag 13388, Windhoek, Namibia.
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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Azumah BK, Addo PG, Dodoo A, Awandare G, Mosi L, Boakye DA, Wilson MD. Experimental demonstration of the possible role of Acanthamoeba polyphaga in the infection and disease progression in Buruli Ulcer (BU) using ICR mice. PLoS One 2017; 12:e0172843. [PMID: 28329001 PMCID: PMC5362167 DOI: 10.1371/journal.pone.0172843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 02/10/2017] [Indexed: 11/18/2022] Open
Abstract
The transmission of Buruli ulcer (BU), caused by Mycobacterium ulcerans (MU), remains puzzling although a number of hypothesis including through bites of infected aquatic insects have been proposed. We report the results of experiments using ICR mice that give credence to our hypothesis that Acanthamoeba species may play a role in BU transmission. We cocultured MU N2 and MU 1615 which expresses red fluorescent protein (RFP) and Acanthamoeba polyphaga (AP), and confirmed infected AP by Ziehl-Neelsen (ZN) staining. We tested for viability of MU inside AP and observed strong RFP signals inside both trophozoites and cysts after 3 and 42 days of coculturing respectively. ICR mice were topically treated, either on shaved intact or shaved pinpricked rumps, with one of the following; MU N2 only (2.25 x 106 colony forming units [CFU] / ml), MU N2:AP coculture (2.96 x 104 CFU: 1.6 x 106 cells/ml), AP only (1.6 x 106 cells/ml), PYG medium and sterile distilled water. Both MU N2 only and MU N2:AP elicited reddening on day (D) 31; edema on D 45 and D 44 respectively, and ulcers on D 49 at pinpricked sites only. To ascertain infectivity and pathogenicity of MU N2 only and MU N2:AP, and compare their virulence, the standard mouse footpad inoculation method was used. MU N2:AP elicited reddening in footpads by D 3 compared to D 14 with MU N2 only of the same dose of MU N2 (2.96 x 104 CFU). ZN-stained MU were observed in both thin sectioned and homogenized lesions, and aspirates from infected sites. Viable MU N2 were recovered from cultures of the homogenates and aspirates. This study demonstrates in ICR mice MU transmission via passive infection, and shows that punctures in the skin are prerequisite for infection, and that coculturing of MU with AP enhances pathogenesis.
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Affiliation(s)
- Bright K. Azumah
- Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Phyllis G. Addo
- Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- * E-mail: (PGA); (MDW)
| | - Alfred Dodoo
- Department of Electron Microscopy and Histopathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Gordon Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Lydia Mosi
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Daniel A. Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Michael D. Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- * E-mail: (PGA); (MDW)
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Fukumoto T, Matsuo J, Okubo T, Nakamura S, Miyamoto K, Oka K, Takahashi M, Akizawa K, Shibuya H, Shimizu C, Yamaguchi H. Acanthamoeba containing endosymbiotic chlamydia isolated from hospital environments and its potential role in inflammatory exacerbation. BMC Microbiol 2016; 16:292. [PMID: 27978822 PMCID: PMC5160005 DOI: 10.1186/s12866-016-0906-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 11/29/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Environmental chlamydiae belonging to the Parachlamydiaceae are obligate intracellular bacteria that infect Acanthamoeba, a free-living amoeba, and are a risk for hospital-acquired pneumonia. However, whether amoebae harboring environmental chlamydiae actually survive in hospital environments is unknown. We therefore isolated living amoebae with symbiotic chlamydiae from hospital environments. RESULTS One hundred smear samples were collected from Hokkaido University Hospital, Sapporo, Japan; 50 in winter (February to March, 2012) and 50 in summer (August, 2012), and used for the study. Acanthamoebae were isolated from the smear samples, and endosymbiotic chlamydial traits were assessed by infectivity, cytokine induction, and draft genomic analysis. From these, 23 amoebae were enriched on agar plates spread with heat-killed Escherichia coli. Amoeba prevalence was greater in the summer-collected samples (15/30, 50%) than those of the winter season (8/30, 26.7%), possibly indicating a seasonal variation (p = 0.096). Morphological assessment of cysts revealed 21 amoebae (21/23, 91%) to be Acanthamoeba, and cultures in PYG medium were established for 11 of these amoebae. Three amoebae contained environmental chlamydiae; however, only one amoeba (Acanthamoeba T4) with an environmental chlamydia (Protochlamydia W-9) was shown the infectious ability to Acanthamoeba C3 (reference amoebae). While Protochlamydia W-9 could infect C3 amoeba, it failed to replicate in immortal human epithelial, although exposure of HEp-2 cells to living bacteria induced the proinflammatory cytokine, IL-8. Comparative genome analysis with KEGG revealed similar genomic features compared with other Protochlamydia genomes (UWE25 and R18), except for a lack of genes encoding the type IV secretion system. Interestingly, resistance genes associated with several antibiotics and toxic compounds were identified. CONCLUSION These findings are the first demonstration of the distribution in a hospital of a living Acanthamoeba carrying an endosymbiotic chlamydial pathogen.
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Affiliation(s)
- Tatsuya Fukumoto
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648 Japan
| | - Junji Matsuo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812 Japan
| | - Torahiko Okubo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812 Japan
| | - Shinji Nakamura
- Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421 Japan
| | - Kentaro Miyamoto
- Miyarisan Pharmaceutical Co., Ltd., 2-3-13-209, Minami, Wako-shi, Saitama 351-0104 Japan
| | - Kentaro Oka
- Miyarisan Pharmaceutical Co., Ltd., 2-3-13-209, Minami, Wako-shi, Saitama 351-0104 Japan
| | - Motomichi Takahashi
- Miyarisan Pharmaceutical Co., Ltd., 2-3-13-209, Minami, Wako-shi, Saitama 351-0104 Japan
| | - Kouji Akizawa
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648 Japan
| | - Hitoshi Shibuya
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648 Japan
| | - Chikara Shimizu
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648 Japan
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812 Japan
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Guimaraes AJ, Gomes KX, Cortines JR, Peralta JM, Peralta RHS. Acanthamoeba spp. as a universal host for pathogenic microorganisms: One bridge from environment to host virulence. Microbiol Res 2016; 193:30-38. [PMID: 27825484 DOI: 10.1016/j.micres.2016.08.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/02/2016] [Accepted: 08/01/2016] [Indexed: 10/21/2022]
Abstract
Free-living amoebas (FLA) are ubiquitous environmental protists that have enormously contributed to the microbiological contamination of water sources. FLAs have displayed resistance to environmental adversities and germicides and have played important roles in the population control of microbial communities due to its predatory behavior and microbicidal activity. However, some organisms have developed resistance to the intracellular milieu of amoebas, as in the case of Acanthamoebas, which in turn, have been functioning as excellent reservoirs for amoeba-resistant microorganisms (ARMs), such as bacteria, viruses and fungi. Little is known about these relationships and interaction mechanisms, but it is speculated that the FLAs need a very broad repertoire or universal class of receptors to bind and recognize these diverse species of microorganisms. By harboring these organisms as a "Trojan Horse", the Achantamoeba has been working as an excellent vector for pathogens. Moreover, studies have demonstrated that the interaction of pathogens with Acanthamoeba results in environmental selective pressure responsible for induction and maintenance of virulence factors and increase in microbial pathogenicity. This phenomenon is correlated to the observation of higher gene number and DNA content of ARMs, when compared to their relatives which are adapted to other hosts, due to allopatric or sympatric gene transfer and acquisition, contradicting the overall genome reduction theory for intracellularly adapted pathogens. Thus, adaptation to FLAs indirectly provided a "learning" environment for pathogens to resist later to macrophages; besides the evolutionary distance, these phagocytes share similar predatory mechanisms, such as phagocytosis and phagolysossomal degradation. In this mini-review, we cover the most important aspects of Acanthamoeba biology and their interactions with endemically important human pathogens.
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Affiliation(s)
- Allan J Guimaraes
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil.
| | - Kamilla Xavier Gomes
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil
| | - Juliana Reis Cortines
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil
| | - José Mauro Peralta
- Departamento de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil.
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Popov NV, Udovikov AI, Eroshenko GA, Karavaeva TB, Yakovlev SA, Porshakov AM, Zenkevich ES, Kutyrev VV. [IMPACT OF CASPIAN SEA LEVEL FLUCTUATIONS ON THE EPIZOOTIC ACTIVITY OF THE CASPIAN SANDY NATURAL PLAGUE FOCUS]. Med Parazitol (Mosk) 2016:12-17. [PMID: 27029140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There is evidence that in 1923-2014 the sharp aggravations of the epizootic situation of plague in the area of its Caspian sandy natural focus after long interepizootic periods are in time with the ups of the Caspian Sea in the extrema of 11-year solar cycles. There were cases of multiple manifestations of plague in the same areas in the epizootic cycles of 1946-1954, 1979-1996, 2001, and 2013-2014. The paper considers the possible role of amebae of the genus Acanthamoeba and nematodes, the representatives of the orders Rhabditida and Tylenchida in the microfocal pattern of plague manifestations.
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Cervero-Aragó S, Rodríguez-Martínez S, Puertas-Bennasar A, Araujo RM. Effect of Common Drinking Water Disinfectants, Chlorine and Heat, on Free Legionella and Amoebae-Associated Legionella. PLoS One 2015; 10:e0134726. [PMID: 26241039 PMCID: PMC4524690 DOI: 10.1371/journal.pone.0134726] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/13/2015] [Indexed: 12/12/2022] Open
Abstract
Chlorine and thermal treatments are the most commonly used procedures to control and prevent Legionella proliferation in drinking water systems of large buildings. However, cases of legionellosis still occur in facilities with treated water. The purpose of this work was to model the effect of temperature and free chlorine applied in similar exposure conditions as in drinking water systems on five Legionella spp. strains and two amoebal strains of the genera Acanthamoeba. Inactivation models obtained were used to determine the effectiveness of the treatments applied which resulted more effective against Legionella than Acanthamoeba, especially those in cystic stages. Furthermore, to determine the influence of the relationship between L. pneumophila and Acanthamoeba spp. on the treatment effectiveness, inactivation models of the bacteria-associated amoeba were also constructed and compared to the models obtained for the free living bacteria state. The Legionella-amoeba association did not change the inactivation models, but it reduced the effectiveness of the treatments applied. Remarkably, at the lowest free chlorine concentration, 0.5 mg L-1, as well as at the lowest temperatures, 50°C and 55°C, the influence of the Legionella-amoeba associate state was the strongest in reducing the effectiveness of the treatments compared to the free Legionella state. Therefore, the association established between L. pneumophila and amoebae in the water systems indicate an increased health risk in proximal areas of the system (close to the tap) where lower free chlorine concentrations and lower temperatures are commonly observed.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Water Hygiene, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Sarah Rodríguez-Martínez
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, 36006, Tivon, Israel
| | - Antoni Puertas-Bennasar
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Rosa M. Araujo
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- * E-mail:
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11
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Karaś MA, Turska-Szewczuk A, Trapska D, Urbanik-Sypniewska T. Growth and Survival of Mesorhizobium loti Inside Acanthamoeba Enhanced Its Ability to Develop More Nodules on Lotus corniculatus. Microb Ecol 2015; 70:566-75. [PMID: 25779926 PMCID: PMC4494150 DOI: 10.1007/s00248-015-0587-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 02/16/2015] [Indexed: 05/12/2023]
Abstract
The importance of protozoa as environmental reservoirs of pathogens is well recognized, while their impact on survival and symbiotic properties of rhizobia has not been explored. The possible survival of free-living rhizobia inside amoebae could influence bacterial abundance in the rhizosphere of legume plants and the nodulation competitiveness of microsymbionts. Two well-characterized strains of Mesorhizobium: Mesorhizobium loti NZP2213 and Mesorhizobium huakuii symbiovar loti MAFF303099 were assayed for their growth ability within the Neff strain of Acanthamoeba castellanii. Although the association ability and the initial uptake rate of both strains were similar, recovery of viable M. huakuii MAFF303099 after 4 h postinfection decreased markedly and that of M. loti NZP2213 increased. The latter strain was also able to survive prolonged co-incubation within amoebae and to self-release from the amoeba cell. The temperature 28 °C and PBS were established as optimal for the uptake of Mesorhizobium by amoebae. The internalization of mesorhizobia was mediated by the mannose-dependent receptor. M. loti NZP2213 bacteria released from amoebae developed 1.5 times more nodules on Lotus corniculatus than bacteria cultivated in an amoebae-free medium.
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Affiliation(s)
- Magdalena A Karaś
- Department of Genetics and Microbiology, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland,
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12
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Cervero-Aragó S, Sommer R, Araujo RM. Effect of UV irradiation (253.7 nm) on free Legionella and Legionella associated with its amoebae hosts. Water Res 2014; 67:299-309. [PMID: 25306486 DOI: 10.1016/j.watres.2014.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 09/15/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
Water systems are the primary reservoir for Legionella spp., where the bacteria live in association with other microorganisms, such as free-living amoebae. A wide range of disinfection treatments have been studied to control and prevent Legionella colonization but few of them were performed considering its relation with protozoa. In this study, the effectiveness of UV irradiation (253.7 nm) using low-pressure lamps was investigated as a disinfection method for Legionella and amoebae under controlled laboratory conditions. UV treatments were applied to 5 strains of Legionella spp., 4 strains of free-living amoeba of the genera Acanthamoeba and Vermamoeba, treating separately trophozoites and cysts, and to two different co-cultures of Legionella pneumophila with the Acanthamoeba strains. No significant differences in the UV inactivation behavior were observed among Legionella strains tested which were 3 logs reduced for fluences around 45 J/m(2). UV irradiation was less effective against free-living amoebae; which in some cases required up to 990 J/m(2) to obtain the same population reduction. UV treatment was more effective against trophozoites compared to cysts; moreover, inactivation patterns were clearly different between the genus Acanthamoeba and Vermamoeba. For the first time data about Vermamoeba vermiformis UV inactivation has been reported in a study. Finally, the results showed that the association of L. pneumophila with free-living amoebae decreases the effectiveness of UV irradiation against the bacteria in a range of 1.5-2 fold. That fact demonstrates that the relations established between different microorganisms in the water systems can modify the effectiveness of the UV treatments applied.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - Regina Sommer
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - Rosa M Araujo
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain.
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13
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Lagkouvardos I, Shen J, Horn M. Improved axenization method reveals complexity of symbiotic associations between bacteria and acanthamoebae. Environ Microbiol Rep 2014; 6:383-388. [PMID: 24992537 DOI: 10.1111/1758-2229.12162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/30/2014] [Indexed: 06/03/2023]
Abstract
Bacteria associated with free-living amoebae have attracted considerable attention because of their role in human disease and as models for studying endosymbiosis. However, the identification and analysis of such novel associations are hindered by the limitations of methods for isolation and axenization of amoebae. Here, we replaced the heat-inactivated Escherichia coli, which is typically used as food source during axenization, with a live E. coli tolC knockout mutant strain hypersensitive to antibiotics. Together with the addition of otherwise sublethal amounts of ampicillin, this approach tripled the success rate and reduced the time required for axenization by at least 3 days. Using this method for two environmental samples, 10 Acanthamoeba strains were isolated, seven of which contained bacterial symbionts. In three cases, amoebae harbouring two phylogenetically distinct symbionts were recovered, supporting a more widespread occurrence of multi-partner symbiotic associations among free-living amoebae.
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Affiliation(s)
- Ilias Lagkouvardos
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
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14
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Vromman F, Laverrière M, Perrinet S, Dufour A, Subtil A. Quantitative monitoring of the Chlamydia trachomatis developmental cycle using GFP-expressing bacteria, microscopy and flow cytometry. PLoS One 2014; 9:e99197. [PMID: 24911516 PMCID: PMC4049595 DOI: 10.1371/journal.pone.0099197] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/12/2014] [Indexed: 02/06/2023] Open
Abstract
Chlamydiae are obligate intracellular bacteria. These pathogens develop inside host cells through a biphasic cycle alternating between two morphologically distinct forms, the infectious elementary body and the replicative reticulate body. Recently, C. trachomatis strains stably expressing fluorescent proteins were obtained. The fluorochromes are expressed during the intracellular growth of the microbe, allowing bacterial visualization by fluorescence microscopy. Whether they are also present in the infectious form, the elementary body, to a detectable level has not been studied. Here, we show that a C. trachomatis strain transformed with a plasmid expressing the green fluorescent protein (GFP) accumulates sufficient quantities of the probe in elementary bodies for detection by microscopy and flow cytometry. Adhesion of single bacteria was detected. The precise kinetics of bacterial entry were determined by microscopy using automated procedures. We show that during the intracellular replication phase, GFP is a convenient read-out for bacterial growth with several advantages over current methods. In particular, infection rates within a non-homogenous cell population are easily quantified. Finally, in spite of their small size, individual elementary bodies are detected by flow cytometers, allowing for direct enumeration of a bacterial preparation. In conclusion, GFP-expressing chlamydiae are suitable to monitor, in a quantitative manner, progression throughout the developmental cycle. This will facilitate the identification of the developmental steps targeted by anti-chlamydial drugs or host factors.
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Affiliation(s)
- François Vromman
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- Centre National de la Recherche Scientifique, URA 2582, Paris, France
- Université Pierre et Marie Curie, Cellule Pasteur UPMC, Paris, France
| | - Marc Laverrière
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- Centre National de la Recherche Scientifique, URA 2582, Paris, France
| | - Stéphanie Perrinet
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- Centre National de la Recherche Scientifique, URA 2582, Paris, France
| | - Alexandre Dufour
- Centre National de la Recherche Scientifique, URA 2582, Paris, France
- Institut Pasteur, Unité d’Analyse d’images biologiques, Paris, France
| | - Agathe Subtil
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- Centre National de la Recherche Scientifique, URA 2582, Paris, France
- * E-mail:
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15
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Wang Y, Ogawa M, Fukuda K, Miyamoto H, Taniguchi H. Isolation and Identification of Mycobacteria from Soils at an Illegal Dumping Site and Landfills in Japan. Microbiol Immunol 2013; 50:513-24. [PMID: 16858142 DOI: 10.1111/j.1348-0421.2006.tb03821.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In order to study the diversity and community of genus Mycobacterium in polluted soils, we tried to isolate mycobacteria from 11 soil samples collected from an illegal dumping site and 3 landfills in Japan. Using culture methods with or without Acanthamoeba culbertsoni, a total of 19 isolates of mycobacteria were obtained from 5 soil samples and 3 of them were isolated only by the co-culture method with the amoeba. Conventional biochemical tests and sequencing of the hsp65, rpoB, and 16S rRNA genes were performed for species identification of 17 of the 19 isolates. Among the 17 isolates, there was one isolate each of Mycobacterium vanbaalenii, Mycobacterium mageritense, Mycobacterium frederiksbergense, M. vanbaalenii or Mycobacterium austroafricanum, and Mycobacterium chubuense or Mycobacterium chlorophenolicum. The remaining 12 isolates could not be precisely identified at the species level. A phylogenic tree based on the hsp65 sequences indicated that 2 of the 12 isolates were novel species. In addition, 4 isolates were phylogenically close to species that degrade polycyclic aromatic hydrocarbons, which induce some cancers in humans. These results demonstrated that there were many hitherto-unreported mycobacteria in the polluted soils, and suggested that some mycobacteria might play roles in the natural attenuation and engineered bioremediation of contaminated sites with other microorganisms.
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Affiliation(s)
- Yan Wang
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan
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16
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Olofsson J, Axelsson-Olsson D, Brudin L, Olsen B, Ellström P. Campylobacter jejuni actively invades the amoeba Acanthamoeba polyphaga and survives within non digestive vacuoles. PLoS One 2013; 8:e78873. [PMID: 24223169 PMCID: PMC3819376 DOI: 10.1371/journal.pone.0078873] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 09/16/2013] [Indexed: 11/18/2022] Open
Abstract
The Gram-negative bacterium Campylobacter jejuni is able to enter, survive and multiply within the free living amoeba Acanthamoeba polyphaga, but the molecular mechanisms behind these events are still unclear. We have studied the uptake and intracellular trafficking of viable and heat killed bacterial cells of the C. jejuni strain 81–176 in A. polyphaga. We found that viable bacteria associated with a substantially higher proportion of Acanthamoeba trophozoites than heat killed bacteria. Furthermore, the kinetics of internalization, the total number of internalized bacteria as well as the intracellular localization of internalized C. jejuni were dramatically influenced by bacterial viability. Viable bacteria were internalized at a high rate already after 1 h of co-incubation and were observed in small vacuoles tightly surrounding the bacteria. In contrast, internalization of heat killed C. jejuni was low at early time points and did not peak until 96 h. These cells were gathered in large spacious vacuoles that were part of the degradative pathway as determined by the uptake of fluorescently labeled dextran. The amount of heat killed bacteria internalized by A. polyphaga did never reach the maximal amount of internalized viable bacteria. These results suggest that the uptake and intracellular survival of C. jejuni in A. polyphaga is bacterially induced.
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Affiliation(s)
- Jenny Olofsson
- Department of Medical Sciences, Infectious Diseases, Uppsala University, Uppsala, Sweden
- Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
- * E-mail:
| | - Diana Axelsson-Olsson
- Marine Microbiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Lars Brudin
- Department of Clinical Physiology, Kalmar County Hospital, Kalmar, Sweden
- Department of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Björn Olsen
- Department of Medical Sciences, Infectious Diseases, Uppsala University, Uppsala, Sweden
- Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Patrik Ellström
- Department of Medical Sciences, Clinical Bacteriology, Uppsala University, Uppsala, Sweden
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17
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Buse HY, Donohue MJ, Ashbolt NJ. Hartmannella vermiformis inhibition of Legionella pneumophila cultivability. Microb Ecol 2013; 66:715-726. [PMID: 23764733 DOI: 10.1007/s00248-013-0250-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/27/2013] [Indexed: 06/02/2023]
Abstract
Hartmannella vermiformis and Acanthamoeba polyphaga are frequently isolated from drinking water and permissive to Legionella pneumophila parasitization. In this study, extracellular factor(s) produced by H. vermiformis and A. polyphaga were assessed for their effects on cultivability of L. pneumophila. Page's amoeba saline (PAS) was used as an encystment medium for H. vermiformis and A. polyphaga monolayers, and the culture supernatants (HvS and ApS, respectively) were assessed against L. pneumophila growth. Compared to PAS and ApS, HvS significantly inhibited L. pneumophila strain Philadelphia-1 (Ph-1) cultivability by 3 log(10) colony forming unit (CFU) mL(-1) after 3 days of exposure compared to <0.5 log(10) CFU mL(-1) reduction of strain Lp02 (P < 0.001). Flow cytometric analysis revealed changes in the percentage and cultivability of three bacterial subpopulations: intact/slightly damaged membrane (ISM), undefined membrane status (UD), and mixed type (MT). After 3 days of HvS exposure, the MT subpopulation decreased significantly (31.6 vs 67.2 %, respectively, P < 0.001), while the ISM and UD subpopulations increased (+26.7 and +6.9 %, respectively) with the ISM subpopulation appearing as viable but nonculturable (VBNC) cells. HvS was separated into two fractions based on molecular weight, with more than 99 % of the L. pneumophila inhibition arising from the <5 kDa fraction (P < 0.001). Liquid chromatography indicated the inhibitory molecule(s) are likely polar and elute from a Novapak C18 column between 6 and 15 min. These results demonstrate that H. vermiformis is capable of extracellular modulation of L. pneumophila cultivability and probably promote the VBNC state for this bacterium.
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Affiliation(s)
- Helen Y Buse
- Dynamac c/o US Environmental Protection Agency, 26 W Martin Luther King Dr, Cincinnati, OH, 45268, USA,
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18
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Sixt BS, Siegl A, Müller C, Watzka M, Wultsch A, Tziotis D, Montanaro J, Richter A, Schmitt-Kopplin P, Horn M. Metabolic features of Protochlamydia amoebophila elementary bodies--a link between activity and infectivity in Chlamydiae. PLoS Pathog 2013; 9:e1003553. [PMID: 23950718 PMCID: PMC3738481 DOI: 10.1371/journal.ppat.1003553] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 06/28/2013] [Indexed: 01/07/2023] Open
Abstract
The Chlamydiae are a highly successful group of obligate intracellular bacteria, whose members are remarkably diverse, ranging from major pathogens of humans and animals to symbionts of ubiquitous protozoa. While their infective developmental stage, the elementary body (EB), has long been accepted to be completely metabolically inert, it has recently been shown to sustain some activities, including uptake of amino acids and protein biosynthesis. In the current study, we performed an in-depth characterization of the metabolic capabilities of EBs of the amoeba symbiont Protochlamydia amoebophila. A combined metabolomics approach, including fluorescence microscopy-based assays, isotope-ratio mass spectrometry (IRMS), ion cyclotron resonance Fourier transform mass spectrometry (ICR/FT-MS), and ultra-performance liquid chromatography mass spectrometry (UPLC-MS) was conducted, with a particular focus on the central carbon metabolism. In addition, the effect of nutrient deprivation on chlamydial infectivity was analyzed. Our investigations revealed that host-free P. amoebophila EBs maintain respiratory activity and metabolize D-glucose, including substrate uptake as well as host-free synthesis of labeled metabolites and release of labeled CO2 from 13C-labeled D-glucose. The pentose phosphate pathway was identified as major route of D-glucose catabolism and host-independent activity of the tricarboxylic acid (TCA) cycle was observed. Our data strongly suggest anabolic reactions in P. amoebophila EBs and demonstrate that under the applied conditions D-glucose availability is essential to sustain metabolic activity. Replacement of this substrate by L-glucose, a non-metabolizable sugar, led to a rapid decline in the number of infectious particles. Likewise, infectivity of Chlamydia trachomatis, a major human pathogen, also declined more rapidly in the absence of nutrients. Collectively, these findings demonstrate that D-glucose is utilized by P. amoebophila EBs and provide evidence that metabolic activity in the extracellular stage of chlamydiae is of major biological relevance as it is a critical factor affecting maintenance of infectivity. The Chlamydiae are a group of bacteria that strictly rely on eukaryotic host cells as a niche for intracellular growth. This group includes major pathogens of humans and animals as well as symbionts of protists. Unlike most other bacteria, chlamydiae alternate between two distinct developmental stages. Here we provide novel insights into the infective stage, the elementary body (EB), which has been described almost a century ago and is commonly referred to as an inert spore-like particle. Our analyses of EBs of the amoeba symbiont Protochlamydia amoebophila provide a detailed overview of their metabolism outside of, and independent from, their natural host cells. We demonstrated that these EBs are capable of respiration and are active in the major routes of central carbon metabolism, including glucose import, biosynthetic reactions, and catabolism for energy generation. Glucose starvation resulted in a rapid decline of metabolic activity in P. amoebophila EBs and a concomitant decrease in their potential to infect new host cells. The human pathogen Chlamydia trachomatis was also dependent on nutrient availability for extracellular survival. The extent of metabolic activity in chlamydial EBs and its consequences for infectivity challenge long-standing textbook knowledge and demonstrate that the infective stage is far more dependent on its environment than previously recognized.
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Affiliation(s)
- Barbara S. Sixt
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Alexander Siegl
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Constanze Müller
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Margarete Watzka
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Anna Wultsch
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Dimitrios Tziotis
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jacqueline Montanaro
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- * E-mail:
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19
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Kao PM, Tung MC, Hsu BM, Hsu SY, Huang JT, Liu JH, Huang YL. Differential Legionella spp. survival between intracellular and extracellular forms in thermal spring environments. Environ Sci Pollut Res Int 2013; 20:3098-3106. [PMID: 23054762 DOI: 10.1007/s11356-012-1159-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/27/2012] [Indexed: 06/01/2023]
Abstract
Legionella are commonly found in natural and man-made aquatic environments and are able to inhabit various species of protozoa. The relationship between the occurrence of Legionella spp. within protozoa and human legionellosis has been demonstrated; however, the proportions of intracellular and extracellular Legionella spp. in the aquatic environment were rarely reported. In this study, we developed a new method to differentiate intracellular and extracellular Legionella spp. in the aquatic environment. Water samples from three thermal spring recreational areas in southeastern Taiwan were collected and analyzed. For each water sample, concurrent measurements were performed for Legionella spp. and their free-living amoebae hosts. The overall detection rate was 32 % (16/50) for intracellular Legionella spp. and 12 % (6/50) for extracellular Legionella spp. The most prevalent host of Legionella spp. was Hartmannella vermiformis. The identified Legionella spp. differed substantially between intracellular and extracellular forms. The results showed that it may be necessary to differentiate intracellular and extracellular forms of Legionella spp.
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Affiliation(s)
- Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, Republic of China
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20
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Messi P, Bargellini A, Anacarso I, Marchesi I, de Niederhäusern S, Bondi M. Protozoa and human macrophages infection by Legionella pneumophila environmental strains belonging to different serogroups. Arch Microbiol 2013; 195:89-96. [PMID: 23135482 DOI: 10.1007/s00203-012-0851-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/11/2012] [Accepted: 10/29/2012] [Indexed: 12/01/2022]
Abstract
Three Legionella pneumophila strains isolated from municipal hot tap water during a multicentric Italian survey and belonging to serogroups 1, 6, 9 and the reference strain Philadelphia-1 were studied to determine the intracellular replication capability and the cytopathogenicity in human monocyte cell line U937 and in an Acanthamoeba polyphaga strain. Our results show that both serogroups 1 and Philadelphia-1 were able to multiply into macrophages inducing cytopathogenicity, while serogroup 6 and ever more serogroup 9 were less efficient in leading to death of the infected macrophages. Both serogroups 1 and 6 displayed a quite good capability of intracellular replication in A. polyphaga, although serogroup 1 was less cytopathogenic than serogroup 6. Serogroup 9, like Philadelphia-1 strain, showed a reduced efficiency of infection and replication and a low cytopathogenicity towards the protozoan. Our study suggests that bacterial pathogenesis is linked to the difference in the virulence expression of L. pneumophila serogroups in both hosts, as demonstrated by the fact that only L. pneumophila serogroup 1 shows the contextual expression of the two virulence traits. Serogroup 6 proves to be a good candidate as pathogen since it shows a good capacity for intracellular replication in protozoan.
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Affiliation(s)
- Patrizia Messi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
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21
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Raftery TD, Lindler H, McNealy TL. Altered host cell-bacteria interaction due to nanoparticle interaction with a bacterial biofilm. Microb Ecol 2013; 65:496-503. [PMID: 23052925 DOI: 10.1007/s00248-012-0128-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 09/15/2012] [Indexed: 06/01/2023]
Abstract
Nanoparticle (NP) use in everyday applications creates the potential for NPs to enter the environment where, in aquatic systems, they are likely to settle on substrates and interact with microbial communities. Legionella pneumophila biofilms are found as part of microbial communities in both natural and man-made environments, especially in man-made cooling systems. The bacterium is the causative agent of Legionnaires' disease. Legionella requires a host cell for replication in the environment, and amoebae commonly serve as this host cell. Our previous work demonstrated significant changes in Legionella biofilm morphology after exposure to 0.7 μg/L gold NPs (AuNPs). Here, we investigate how these morphology changes alter host-bacteria interactions using Acanthamoeba polyphaga as a model. Host-bacteria-NP interactions are affected by NP characteristics. Biofilms exposed to 4- and 18-nm, citrate-capped, spherical AuNPs significantly altered the grazing ability of A. polyphaga, which was not observed in biofilms exposed to 24-nm polystyrene beads. Uptake and replication of NP-exposed planktonic L. pneumophila within A. polyphaga were not altered regardless of NP size or core chemistry. Nanomaterial effects on the interaction of benthic organisms and bacteria may be directly or, as shown here, indirectly dependent on bacterial morphology. NP contamination therefore may alter interactions in a normal ecosystem function.
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Affiliation(s)
- Tara D Raftery
- Institute of Environmental Toxicology (CU-ENTOX), Clemson University, Clemson, SC 29634, USA.
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Abstract
Although the study of protozoology has been active for centuries, very few current academic curricula incorporate requirements or even options for coursework on the study of protists; yet, protozoa are becoming widely recognized by investigators as organisms that play a significant role in the evolution, pathogenicity, protection and amplification of human pathogens in the environment. This is particularly true for the study of Legionella, as this accidental human pathogen has naturally evolved to infect protozoa in fresh water environments. Researchers have made great progress in the study of pathogenicity, evolution, and ecology of Legionella and its protozoan hosts, which include amoebae and ciliated protozoa. Our own collaboration in this field has been active for over a decade, and we have gained a valuable experience working with these protozoa, particularly aspects of their biology and the methods needed to address new experimental concepts. Therefore, in this chapter we provide the most effective procedures that we have developed or modified through our years of practice. We also offer notes on what procedures, in our opinion, should be avoided; and we provide the rationale for such precautions.
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Affiliation(s)
- Sharon G Berk
- Center for Management, Utilization and Protection of Water Resources, Tennessee Technological University, Cookeville, TN, USA.
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23
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Ensminger AW, Yassin Y, Miron A, Isberg RR. Experimental evolution of Legionella pneumophila in mouse macrophages leads to strains with altered determinants of environmental survival. PLoS Pathog 2012; 8:e1002731. [PMID: 22693450 PMCID: PMC3364954 DOI: 10.1371/journal.ppat.1002731] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 04/19/2012] [Indexed: 12/03/2022] Open
Abstract
The Gram-negative bacterium, Legionella pneumophila, is a protozoan parasite and accidental intracellular pathogen of humans. We propose a model in which cycling through multiple protozoan hosts in the environment holds L. pneumophila in a state of evolutionary stasis as a broad host-range pathogen. Using an experimental evolution approach, we tested this hypothesis by restricting L. pneumophila to growth within mouse macrophages for hundreds of generations. Whole-genome resequencing and high-throughput genotyping identified several parallel adaptive mutations and population dynamics that led to improved replication within macrophages. Based on these results, we provide a detailed view of the population dynamics of an experimentally evolving bacterial population, punctuated by frequent instances of transient clonal interference and selective sweeps. Non-synonymous point mutations in the flagellar regulator, fleN, resulted in increased uptake and broadly increased replication in both macrophages and amoebae. Mutations in multiple steps of the lysine biosynthesis pathway were also independently isolated, resulting in lysine auxotrophy and reduced replication in amoebae. These results demonstrate that under laboratory conditions, host restriction is sufficient to rapidly modify L. pneumophila fitness and host range. We hypothesize that, in the environment, host cycling prevents L. pneumophila host-specialization by maintaining pathways that are deleterious for growth in macrophages and other hosts. Legionella pneumophila is an accidental pathogen of humans, responsible for the severe, often-fatal pneumonia known as Legionnaires' disease. In the environment, L. pneumophila survives and replicates within protozoa by co-opting the intracellular machinery of these microbial predators. These freshwater encounters between bacteria and protozoa likely provided L. pneumophila with the selective pressures required to evolve into an intracellular pathogen. Many of the host pathways that L. pneumophila manipulates during infection are highly conserved and this is presumably what allows L. pneumophila to infect human cells. It is likely that L. pneumophila is suboptimally adapted to replication within mammalian cells, however, as replication within human cells is thought to be an evolutionary dead end. In this study, we developed an experimental evolution approach to determine what unique selective pressures might be present within mammalian hosts and how these pressures might modify this pathogen. We subjected L. pneumophila to continuous passage within mouse macrophages for several months, selecting for spontaneous mutations that resulted in improved fitness within these cells. We sequenced the genomes of each of the adapted strains, measured the population dynamics of each evolving population, and identified mutations that improve replication in mammalian cells and alter bacterial fitness in amoebae.
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Affiliation(s)
- Alexander W. Ensminger
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Public Health Ontario, Toronto, Ontario, Canada
- * E-mail: (AWE); (RRI)
| | - Yosuf Yassin
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Alexander Miron
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Ralph R. Isberg
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (AWE); (RRI)
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Lamrabet O, Merhej V, Pontarotti P, Raoult D, Drancourt M. The genealogic tree of mycobacteria reveals a long-standing sympatric life into free-living protozoa. PLoS One 2012; 7:e34754. [PMID: 22511965 PMCID: PMC3325273 DOI: 10.1371/journal.pone.0034754] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 03/08/2012] [Indexed: 02/07/2023] Open
Abstract
Free-living protozoa allow horizontal gene transfer with and between the microorganisms that they host. They host mycobacteria for which the sources of transferred genes remain unknown. Using BLASTp, we searched within the genomes of 15 mycobacteria for homologous genes with 34 amoeba-resistant bacteria and the free-living protozoa Dictyostelium discoideum. Subsequent phylogenetic analysis of these sequences revealed that eight mycobacterial open-reading frames (ORFs) were probably acquired via horizontal transfer from beta- and gamma-Proteobacteria and from Firmicutes, but the transfer histories could not be reliably established in details. One further ORF encoding a pyridine nucleotide disulfide oxidoreductase (pyr-redox) placed non-tuberculous mycobacteria in a clade with Legionella spp., Francisella spp., Coxiella burnetii, the ciliate Tetrahymena thermophila and D. discoideum with a high reliability. Co-culturing Mycobacterium avium and Legionella pneumophila with the amoeba Acanthamoeba polyphaga demonstrated that these two bacteria could live together in amoebae for five days, indicating the biological relevance of intra-amoebal transfer of the pyr-redox gene. In conclusion, the results of this study support the hypothesis that protists can serve as a source and a place for gene transfer in mycobacteria.
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Affiliation(s)
- Otmane Lamrabet
- URMITE CNRS-IRD UMR 6236, IFR48, Méditerranée Infection, Aix-Marseille Université, Marseille, France
| | - Vicky Merhej
- URMITE CNRS-IRD UMR 6236, IFR48, Méditerranée Infection, Aix-Marseille Université, Marseille, France
| | - Pierre Pontarotti
- Equipe Evolution Biologique et Modélisation UMR 6632, IRF48, Aix-Marseille Université/CNRS, Marseille, France
| | - Didier Raoult
- URMITE CNRS-IRD UMR 6236, IFR48, Méditerranée Infection, Aix-Marseille Université, Marseille, France
| | - Michel Drancourt
- URMITE CNRS-IRD UMR 6236, IFR48, Méditerranée Infection, Aix-Marseille Université, Marseille, France
- * E-mail:
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Lienard J, Croxatto A, Prod'hom G, Greub G. Estrella lausannensis, a new star in the Chlamydiales order. Microbes Infect 2011; 13:1232-41. [PMID: 21816232 DOI: 10.1016/j.micinf.2011.07.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 07/07/2011] [Accepted: 07/07/2011] [Indexed: 11/17/2022]
Abstract
Originally, the Chlamydiales order was represented by a single family, the Chlamydiaceae, composed of several pathogens, such as Chlamydia trachomatis, Chlamydia pneumoniae, Chlamydia psittaci and Chlamydia abortus. Recently, 6 new families of Chlamydia-related bacteria have been added to the Chlamydiales order. Most of these obligate intracellular bacteria are able to replicate in free-living amoebae. Amoebal co-culture may be used to selectively isolate amoeba-resisting bacteria. This method allowed in a previous work to discover strain CRIB 30, from an environmental water sample. Based on its 16S rRNA gene sequence similarity with Criblamydia sequanensis, strain CRIB 30 was considered as a new member of the Criblamydiaceae family. In the present work, phylogenetic analyses of the genes gyrA, gyrB, rpoA, rpoB, secY, topA and 23S rRNA as well as MALDI-TOF MS confirmed the taxonomic classification of strain CRIB 30. Morphological examination revealed peculiar star-shaped elementary bodies (EBs) similar to those of C. sequanensis. Therefore, this new strain was called "Estrella lausannensis". Finally, E. lausannensis showed a large amoebal host range and a very efficient replication rate in Acanthamoeba species. Furthermore, E. lausannensis is the first member of the Chlamydiales order to grow successfully in the genetically tractable Dictyostelium discoideum, which opens new perspectives in the study of chlamydial biology.
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MESH Headings
- Acanthamoeba/microbiology
- Amoeba/microbiology
- Chlamydiales/classification
- Chlamydiales/genetics
- Chlamydiales/growth & development
- Chlamydiales/isolation & purification
- Coculture Techniques
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- Dictyostelium/microbiology
- Genes, rRNA/genetics
- Microscopy, Fluorescence
- Phylogeny
- RNA, Ribosomal, 16S/analysis
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Affiliation(s)
- Julia Lienard
- Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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Xuan YH, Cui CQ, Zheng SZ. [Sequence analysis of 16S rDNA gene of endosymbiont of Acanthamoeba sp. CB/S1 isolated from soil]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2011; 29:98-100. [PMID: 21826891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The endosymbiont of Acanthamoeba sp. CB/SI was identified by orcein-carmine staining and 16S rDNA sequence analysis. The endosymbiont bacteria were rod-shaped and darkly stained, and irregularly localized within the cytoplasm. The length of the 16S rDNA was 1534 bp and its DNA sequence was closely related to those of Candidatus Amoebophilus asiaticus and Acanthamoeba sp. KA/E21 with 98% homology. Phylogenetic analysis showed that the endosymbiont of CB/SI, the endosymbiont of KA/E21, Candidatus Amoebophilus asiaticus, the endosymbiont of Ixodes scapularis, and the endosymbiont of Encarsia pergandiella constitute a monophyletic lineage in phylogenetic tree.
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Affiliation(s)
- Ying-hua Xuan
- Department of Pathogenic Biology, College of Basic Medicine, Yanbian University, Yanji 133000, China
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27
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Huang SW, Hsu BM. Isolation and identification of Acanthamoeba from Taiwan spring recreation areas using culture enrichment combined with PCR. Acta Trop 2010; 115:282-7. [PMID: 20434423 DOI: 10.1016/j.actatropica.2010.04.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 03/22/2010] [Accepted: 04/21/2010] [Indexed: 11/30/2022]
Abstract
In the study, 52 spring water samples were collected from three hot spring recreation areas in northern Taiwan and Acanthamoebae were isolated from 11 samples (21.2%) on two hot spring recreation areas and mainly present in the hot spring water, hot tubs and wastewater. The most frequently identified Acanthamoeba genotype was T15, followed by T6, and then T5. Genotype T1, T2, T3 and T4 were detected once, respectively. The presence or absence of Acanthamoeba within the spring water samples showed significant difference with the levels of heterotrophic plate counts (HPC). Genotype T2-T6 and genotype T15, the organism responsible for Acanthamoeba keratitis, and the Acanthamoeba species organism, retained pathogenic Legionella, and should be considered a potential health threat associated with human activities in spring recreation areas.
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Affiliation(s)
- Shih-Wei Huang
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
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Iovieno A, Ledee DR, Miller D, Alfonso EC. Detection of bacterial endosymbionts in clinical acanthamoeba isolates. Ophthalmology 2010; 117:445-52, 452.e1-3. [PMID: 20031220 DOI: 10.1016/j.ophtha.2009.08.033] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 08/23/2009] [Accepted: 08/25/2009] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To determine the presence of 4 clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK. DESIGN Experimental study. PARTICIPANTS Acanthamoeba isolates (N = 37) recovered from the cornea and contact lens paraphernalia of 23 patients with culture-proven AK and 1 environmental isolate. METHODS Acanthamoeba isolates were evaluated for the presence of microbial endosymbionts belonging to the bacterial genera Legionella, Pseudomonas, Mycobacterium, and Chlamydia using molecular techniques (polymerase chain reaction and sequence analysis, fluorescence in situ hybridization) and transmission electron microscopy. Corneal toxicity and virulence of Acanthamoeba isolates with and without endosymbionts were compared using a cytopathic effect (CPE) assay on human corneal epithelial cells in vitro. Initial visual acuity, location and characteristics of the infiltrate, time to detection of the infection, and symptom duration at presentation were evaluated in all patients. MAIN OUTCOME MEASURES Prevalence and potential pathobiology of bacterial endosymbionts detected in Acanthamoeba isolates recovered from AK. RESULTS Twenty-two (59.4%) of the 38 cultures examined contained at least 1 bacterial endosymbiont. One isolate contained 2 endosymbionts, Legionella and Chlamydia, confirmed by fluorescence in situ hybridization. Corneal toxicity (CPE) was significantly higher for Acanthamoeba-hosting endosymbionts compared with isolates without endosymbionts (P<0.05). Corneal pathogenic endosymbionts such as Pseudomonas and Mycobacterium enhanced Acanthamoeba CPE significantly more than Legionella (P<0.05). In the presence of bacterial endosymbionts, there was a trend toward worse initial visual acuity (P>0.05), central location (P<0.05), absence of radial perineuritis (P<0.05), delayed time to detection (P>0.05), and longer symptom duration at presentation (P>0.05). CONCLUSIONS Most Acanthamoeba isolates responsible for AK harbor 1 or more bacterial endosymbionts. The presence of endosymbionts enhances the corneal pathogenicity of Acanthamoeba isolates and may impact detection time and clinical features of AK.
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Affiliation(s)
- Alfonso Iovieno
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami-Miller School of Medicine, Miami, Florida 33136, USA
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30
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Abstract
Chlamydiae are obligate intracellular bacteria, parasites of a variety of eukaryotes ranging from amoebae to humans. Among them, the family Parachlamydiaceae comprises endosymbionts of amoebae, mainly Acanthamoeba, currently investigated as emerging pathogens of humans and other vertebrates. 16S rDNA-based PCR culture-independent studies in environmental samples have demonstrated the presence of Chlamydiales in various types of nonmedical habitats. Here we reviewed the biology of the Parachlamydiaceae, and more particularly those studies reporting molecular evidences for their presence in the environment, with a re-analysis of the 16S rDNA phylotypes.
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Affiliation(s)
- Daniele Corsaro
- CHLAREAS Chlamydia Research Association, Vandoeuvre-lès-Nancy, France.
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31
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Schmitz-Esser S, Toenshoff ER, Haider S, Heinz E, Hoenninger VM, Wagner M, Horn M. Diversity of bacterial endosymbionts of environmental acanthamoeba isolates. Appl Environ Microbiol 2008; 74:5822-31. [PMID: 18641160 PMCID: PMC2547052 DOI: 10.1128/aem.01093-08] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 07/11/2008] [Indexed: 11/20/2022] Open
Abstract
Free-living amoebae are frequent hosts for bacterial endosymbionts. In this study, the symbionts of eight novel environmental Acanthamoeba strains isolated from different locations worldwide were characterized. Phylogenetic analysis revealed that they were related to one of four evolutionary lineages of amoeba symbionts recognized previously. This study provides evidence for the existence of only a small number of phylogenetically well-separated groups of obligate intracellular endosymbionts of acanthamoebae with global distribution.
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MESH Headings
- Acanthamoeba/genetics
- Acanthamoeba/microbiology
- Animals
- Bacteria/classification
- Bacteria/genetics
- Biodiversity
- DNA, Bacterial/genetics
- DNA, Protozoan/genetics
- Genes, Bacterial
- Genes, Protozoan
- Genes, rRNA
- Geologic Sediments/microbiology
- Molecular Sequence Data
- Phylogeny
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 18S/genetics
- Sequence Analysis, DNA
- Soil Microbiology
- Symbiosis
- Water Microbiology
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Affiliation(s)
- Stephan Schmitz-Esser
- Department of Microbial Ecology, University of Vienna, Althanstr. 14, 1090 Vienna, Austria
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Scheid P, Zöller L, Pressmar S, Richard G, Michel R. An extraordinary endocytobiont in Acanthamoeba sp. isolated from a patient with keratitis. Parasitol Res 2008; 102:945-50. [PMID: 18210154 DOI: 10.1007/s00436-007-0858-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 12/10/2007] [Indexed: 11/24/2022]
Abstract
In the present article, the detection and the development of a parasitic endocytobiont within host amoebae (Acanthamoeba sp.) recently isolated from the contact lens and the inflamed eye of a patient with keratitis is presented. An otherwise healthy 55-year-old female patient presented with keratitis in her inflamed left eye. She was a contact lens wearer and had no history of a corneal trauma. Acanthamoebae as well as other smaller free-living amoebae could be detected from the fluid of the contact lens storage cases by culture methods. A successful therapy could be provided consequently. Two of these Acanthamoeba strains showed intracellular aggregating organisms. Within 2 to 3 days, the host amoebae ruptured, and numerous microorganisms were released. We succeeded in detecting the mechanism of infection and intrusion of this organisms by using light and electron microscopy. Infection with this endocytobiont is a suitable model for studying the host-parasite relations while the parasites use their hosts as so-called Trojan horses (see Barker, Lambert, Brown, Infect Immun 61:3503-3510, 1992).
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Affiliation(s)
- P Scheid
- Laboratory of Medical Parasitology, Central Institute of the Bundeswehr Medical Service Koblenz, Andernacherstr 100, 56070 Koblenz, Germany.
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Abstract
Experiments with insects, protozoa, nematodes, and slime molds have recently come to the forefront in the study of host–fungal interactions. Many of the virulence factors required for pathogenicity in mammals are also important for fungal survival during interactions with non-vertebrate hosts, suggesting that fungal virulence may have evolved, and been maintained, as a countermeasure to environmental predation by amoebae and nematodes and other small non-vertebrates that feed on microorganisms. Host innate immune responses are also broadly conserved across many phyla. The study of the interaction between invertebrate model hosts and pathogenic fungi therefore provides insights into the mechanisms underlying pathogen virulence and host immunity, and complements the use of mammalian models by enabling whole-animal high throughput infection assays. This review aims to assist researchers in identifying appropriate invertebrate systems for the study of particular aspects of fungal pathogenesis.
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Xuan YH, Yu HS, Jeong HJ, Seol SY, Chung DI, Kong HH. Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients. Korean J Parasitol 2007; 45:1-9. [PMID: 17374972 PMCID: PMC2526339 DOI: 10.3347/kjp.2007.45.1.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.
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Affiliation(s)
- Ying-Hua Xuan
- Department of Parasitology, Kyungpook National University School of Medicine, Taegu 700-422, Korea
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Yu HS, Jeong HJ, Hong YC, Seol SY, Chung DI, Kong HH. Natural occurrence of Mycobacterium as an endosymbiont of Acanthamoeba isolated from a contact lens storage case. Korean J Parasitol 2007; 45:11-8. [PMID: 17374973 PMCID: PMC2526340 DOI: 10.3347/kjp.2007.45.1.11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Recent in vitro studies have revealed that a certain Mycobacterium can survive and multiply within free-living amoebae. It is believed that protozoans function as host cells for the intracellular replication and evasion of Mycobacterium spp. under harmful conditions. In this study, we describe the isolation and characterization of a bacterium naturally observed within an amoeba isolate acquired from a contact lens storage case. The bacterium multiplied within Acanthamoeba, but exerted no cytopathic effects on the amoeba during a 6-year amoebic culture. Transmission electron microscopy showed that the bacteria were randomly distributed within the cytoplasm of trophozoites and cysts of Acanthamoeba. On the basis of the results of 18S rRNA gene analysis, the amoeba was identified as A. lugdunensis. A 16S rRNA gene analysis placed this bacterium within the genus Mycobacterium. The bacterium evidenced positive reactivity for acid-fast and fluorescent acid-fast stains. The bacterium was capable of growth on the Middlebrook 7H11-Mycobacterium-specific agar. The identification and characterization of bacterial endosymbionts of free-living protozoa bears significant implications for our understanding of the ecology and the identification of other atypical mycobacterial pathogens.
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Affiliation(s)
- Hak Sun Yu
- Department of Parasitology, Pusan National University School of Medicine, Busan 602-739, Korea
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Abstract
Acanthamoebae are ubiquitous free-living amoebae and important predators of microbial communities. They frequently contain obligate intracellular bacterial symbionts, which show a worldwide distribution. All Acanthamoeba spp. described so far harboured no or only a single specific endosymbiont phylotype, and in some cases evidence for coevolution between the symbiotic bacteria and the amoeba host has been reported. In this study we have isolated and characterized an Acanthamoeba sp. (strain OEW1) showing a stable symbiotic relationship with two morphologically different endosymbionts. 16S rRNA sequence analysis assigned these symbionts to the candidate genus Procabacter (Betaproteobacteria) and the genus Parachlamydia (Chlamydiae) respectively. Fluorescence in situ hybridization and transmission electron microscopy confirmed the affiliation of the endosymbionts and showed their co-occurrence in the amoeba host cells and their intracellular location within separate compartments enclosed by host-derived membranes. Further analysis of this stable relationship should provide novel insights into the complex interactions of intracellular multiple-partner associations.
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Affiliation(s)
| | | | | | | | | | - Matthias Horn
- For correspondence. E-mail ; Tel. (+43) 1 4277 54393; Fax (+43) 1 4277 54389
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37
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García MT, Jones S, Pelaz C, Millar RD, Abu Kwaik Y. Acanthamoeba polyphaga resuscitates viable non-culturable Legionella pneumophila after disinfection. Environ Microbiol 2007; 9:1267-77. [PMID: 17472639 DOI: 10.1111/j.1462-2920.2007.01245.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amoebae are the natural hosts for Legionella pneumophila and play essential roles in bacterial ecology and infectivity to humans. When L. pneumophila colonizes an aquatic installation, it can persist for years despite repeated treatments with disinfectants. We hypothesized that freshwater amoebae play an important role in bacterial resistance to disinfectants, and in subsequent resuscitation of viable non-culturable (VNC) L. pneumophila that results in re-emergence of the disease-causing strain in the disinfected water source. Our work showed that in the absence of Acanthamoeba polyphaga, seven L. pneumophila strains became non-culturable after treatment by 256 p.p.m. of sodium hypochlorite (NaOCl). In contrast, intracellular L. pneumophila within A. polyphaga was resistant to 1024 p.p.m. of NaOCl. In addition, L. pneumophila-infected A. polyphaga exhibited increased resistance to NaOCl. When chlorine-sterilized water samples were co-cultured with A. polyphaga, the non-culturable L. pneumophila were resuscitated and proliferated robustly within A. polyphaga. Upon treatment by NaOCl, uninfected amoebae differentiated into cysts within 48 h. In contrast, L. pneumophila-infected A. polyphaga failed to differentiate into cysts, and L. pneumophila was never detected in cysts of A. polyphaga. We conclude that amoebic trophozoites protect intracellular L. pneumophila from eradication by NaOCl, and play an essential role in resuscitation of VNC L. pneumophila in NaOCl-disinfected water sources. Intracellular L. pneumophila within trophozoites of A. polyphaga block encystation of the amoebae, and the resistance of both organisms to NaOCl is enhanced. To ensure long-term eradication and complete loss of the VNC state of L. pneumophila, we recommend that Legionella-protozoa co-culture should be an important tool to ensure complete loss of the VNC state of L. pneumophila.
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Affiliation(s)
- María Teresa García
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, USA
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Molmeret M, Santic' M, Asare R, Carabeo RA, Abu Kwaik Y. Rapid escape of the dot/icm mutants of Legionella pneumophila into the cytosol of mammalian and protozoan cells. Infect Immun 2007; 75:3290-304. [PMID: 17438033 PMCID: PMC1932949 DOI: 10.1128/iai.00292-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Legionella pneumophila-containing phagosome evades endocytic fusion and intercepts endoplasmic reticulum (ER)-to-Golgi vesicle traffic, which is believed to be mediated by the Dot/Icm type IV secretion system. Although phagosomes harboring dot/icm mutants are thought to mature through the endosomal-lysosomal pathway, colocalization studies with lysosomal markers have reported contradictory results. In addition, phagosomes harboring the dot/icm mutants do not interact with endocytosed materials, which is inconsistent with maturation of the phagosomes in the endosomal-lysosomal pathway. Using multiple strategies, we show that the dot/icm mutants defective in the Dot/Icm structural apparatus are unable to maintain the integrity of their phagosomes and escape into the cytoplasm within minutes of entry into various mammalian and protozoan cells in a process independent of the type II secretion system. In contrast, mutants defective in cytoplasmic chaperones of Dot/Icm effectors and rpoS, letA/S, and letE regulatory mutants are all localized within intact phagosomes. Importantly, non-dot/icm L. pneumophila mutants whose phagosomes acquire late endosomal-lysosomal markers are all located within intact phagosomes. Using high-resolution electron microscopy, we show that phagosomes harboring the dot/icm transporter mutants do not fuse to lysosomes but are free in the cytoplasm. Inhibition of ER-to-Golgi vesicle traffic by brefeldin A does not affect the integrity of the phagosomes harboring the parental strain of L. pneumophila. We conclude that the Dot/Icm transporter is involved in maintaining the integrity of the L. pneumophila phagosome, independent of interception of ER-to-Golgi vesicle traffic, which is a novel function of type IV secretion systems.
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Affiliation(s)
- Maëlle Molmeret
- Department of Microbiology and Immunology, University of Louisville College of Medicine, Louisville, KY 40292, USA
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Abstract
Legionella pneumophila is the Gram-negative bacterial agent of Legionnaires' disease, an acute, often fatal pneumonia. L. pneumophila infects alveolar macrophages, evading the antimicrobial defences of the phagocyte by preventing fusion of the phagosome with lysosomes and avoiding phagosome acidification. The bacteria then modulate the composition of the vacuole so that it takes on the characteristics of the endoplasmic reticulum. Similar events occur when the bacteria infect unicellular protozoa. It is thought that replication in fresh water protozoa provides an environmental reservoir for the organism. Several effector proteins are delivered to the host by the Icm/Dot type IV secretion system (TFSS). Some of these have been shown to participate in the trafficking of the Legionella phagosome. Here we describe the ability of the Icm/Dot TFSS to translocate two effectors, LepA and LepB, that play a role in the non-lytic release of Legionella from protozoa. We report that translocation of the Lep proteins is inhibited by agents that depolymerize actin filaments and that effectors may be secreted into the extracellular medium upon cell contact. Depletion of the Lep proteins by deletion of their genes results in increased ability to lyse red blood cells. In contrast, overexpression of Lep-containing hybrid proteins appears to specifically inhibit the activity of the Icm/Dot TFSS and may prevent the delivery of other effectors that are critical for intracellular multiplication.
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Affiliation(s)
- John Chen
- Department of Microbiology, Columbia University Medical Center, New York, NY 10032, USA
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Abstract
Outbreaks due to Mycobacterium xenopi have been linked with contaminated water. M. xenopi has been shown to interact with the biofilm formed in water distribution systems and to be hosted by free-living Acanthamoeba. The present study investigated the interaction between M. xenopi and A. polyphaga amoeba, and between M. xenopi and human fibroblast HEL cells. Examination using the light microscopy together with electronic and confocal microscopy demonstrated that M. xenopi was located within the amoeba and in HEL cells. The Light Cycler measurement of the M. xenopi:A. polyphaga DNA ratio and the M. xenopi:HEL cell DNA ratio demonstrated intra-amoebal and intracellular growth of M. xenopi with doubling-times of five-days and 10 days, respectively. Intra-amoebal M. xenopi survived protozoan encystment and germination. These data demonstrate that M. xenopi is a facultative intra-amoebal and intracellular pathogen. Testing intra-amoebal M. xenopi might be necessary to properly evaluate decontamination procedures for hospital water supply systems in order to achieve eradication.
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Affiliation(s)
- M Drancourt
- Rickettsia Unit, Faculty of Medicine, Mediterranean University, Marseille, France.
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Hwang MG, Katayama H, Ohgaki S. Effect of intracellular resuscitation of Legionella pneumophila in Acanthamoeba polyphage cells on the antimicrobial properties of silver and copper. Environ Sci Technol 2006; 40:7434-9. [PMID: 17181000 DOI: 10.1021/es060412t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The property of Legionella pneumophila entering into a viable but noncultivable (VBNC) state under drinking water conditions (50 mL, pH 7.0, and 25 degrees C) and the intracellular resuscitation in Acanthamoeba polyphage cells were investigated. Then, the survival profiles of L. pneumophila residing in the planktonic phase and the endosymbiosis phase against antimicrobial silver and copper reagents were differentially compared with the case of Pseudomonas aeruginosa. The number of L. pneumophila in a cultivable state was rapidly reduced to below the detection limit (5.0 log reduction) within 30 days of incubation in synthetic drinking water, while the number of L. pneumophila in a viable state varied in only 0.1 log reduction during the same period, and the levels were sustained constantly for 190 days; in contrast, P. aeruginosa multiplied even in drinking water and continuously maintained its cultivability and viabilityfor 190 days. Distinctively, the numbers of E. coli in both cultivable and viable states were simultaneously diminished as 3.0 log and 1.6 log reduction. The cultivability of L. pneumophila in the VBNC state was recovered and started to multiply after coincubation with A. polyphage in the same environment (initial population of inoculated amoeba was adjusted as 1.0 x 10(5) amoeba/ mL), and P. aeruginosa also multiplied in amoeba cells. Finally, the populations of L. pneumophila in the planktonic phase after 10 days coincubation were detected at 1.7 x 10(7) CFU/mL, and this population was considered to have originated from the release of bacteria residing inside amoeba caused by the destruction of amoeba cells. Bacteria in the planktonic phase that were exposed to silver and copper were completely inactivated (more than 7 log reduction) within 30 min, while bacteria in the endosymbiosis phase showed much higher resistance against the exposure to the same concentrations of silver and copper. L. pneumophila and P. aeruginosa in A. polyphage cells survived to levels of 5.6 x 10(1) and 1.1 x 10(1) CFU/mL at the silver exposure (0.1 mgAg/L) and 7.3 x 10(3) and 6.1 x 10(4) CFU/ mL at the copper exposure (1.0 mgCu/L), respectively, after 7 days.
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Affiliation(s)
- Myoung Goo Hwang
- Department of Urban Engineering, The University of Tokyo, 3-1-7 Hongo Bunkyo, Tokyo 133-8656, Japan.
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Jung SY, Matin A, Kim KS, Khan NA. The capsule plays an important role in Escherichia coli K1 interactions with Acanthamoeba. Int J Parasitol 2006; 37:417-23. [PMID: 17157852 DOI: 10.1016/j.ijpara.2006.10.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/12/2006] [Accepted: 10/16/2006] [Indexed: 01/06/2023]
Abstract
Escherichia coli K1 is shown to bind to, associate with, invade and survive inside Acanthamoeba, but the precise mechanisms associated with these events are unclear. We have previously shown that outer membrane protein A and lipopolysaccharide are critical bacterial determinants involved in E. coli K1 interactions with Acanthamoeba. Using an isogenic K1 capsule-deletion mutant (lacking the neuDB genes cluster that is necessary for the production of cytoplasmic precursors to the exopolysaccharide capsule), we observed that the capsule modulates and enhances E. coli K1 association and survival inside Acanthamoeba. The capsule-deletion mutant exhibited significantly reduced association compared with the wild type strain, E44. Similarly, the K1 capsule-deletion mutant exhibited limited ability for invasion/uptake by and survival inside Acanthamoeba. Next, we determined whether E. coli K1 survive inside Acanthamoeba during the encystment process and that viable bacteria can be isolated from the mature cysts. Using encystment assays, our findings revealed that E. coli K1, but not its capsule-deletion mutant, exhibit survival inside Acanthamoeba cysts. We believe this is the first demonstration that the K1 capsule plays an important role in E. coli K1 interactions with Acanthamoeba.
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Affiliation(s)
- Suk-Yul Jung
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London WC1E 7HX, England, UK
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Jeong HJ, Jang ES, Han BI, Lee KH, Ock MS, Kong HH, Chung DI, Seol SY, Cho DT, Yu HS. Acanthamoeba: could it be an environmental host of Shigella? Exp Parasitol 2006; 115:181-6. [PMID: 16978610 DOI: 10.1016/j.exppara.2006.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 07/26/2006] [Accepted: 08/02/2006] [Indexed: 01/06/2023]
Abstract
Shigellosis is a serious public health problem in Korea, because large outbreaks of Shigella sonnei infections were recorded in many parts of the country during the period 1998-2000. However, the epidemiological features of shigellosis are not well known. In this study, we devised conditions suitable for the growth and replication of Shigella in an amoebic intracellular environment, and investigate whether medium conditions affect the survival and replication of Shigella within Acanthamoeba. We evaluated the uptake rates of invasive and non invasive S. sonnei strains by three Acanthamoeba species, namely, A. castellanii Neff, A. astronyxis Ray & Hayes, and A. healyi OC-3A. When A. castellanii Neff was infected with S. sonnei 99OBS1 or 80DH248, shigellae was maintained for a longer time in cytoplasms than in other Acanthamoeba species. S. sonnei 99OBS1 strain (a virulent strain) was recovered in higher numbers than the non-virulent S. sonnei 80DH248 strain in all experiments. Moreover, S. sonnei was more easily engulfed by Acanthamoeba at 18 degrees C. The shigellae uptake rates of Neff strain, which was cultured in free-media (less nutrition), were higher (>10-fold) than those observed in original amoeba culture media (PYG medium) in all time points. S. sonnei 99OBS1 was localized, with an intact membrane, to the vacuoles of Acanthamoeba. We conclude that free-living amoebae more likely act as environmental hosts for shigellae, and thus, may have contributed to outbreaks of shigellosis in Korea.
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Affiliation(s)
- Hae Jin Jeong
- Department of Parasitology, School of Medicine, Pusan National University, 1-10 Ami-dong, Seo-gu, Busan 602-739, Republic of Korea
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Adékambi T, Ben Salah S, Khlif M, Raoult D, Drancourt M. Survival of environmental mycobacteria in Acanthamoeba polyphaga. Appl Environ Microbiol 2006; 72:5974-81. [PMID: 16957218 PMCID: PMC1563627 DOI: 10.1128/aem.03075-05] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Accepted: 06/16/2006] [Indexed: 11/20/2022] Open
Abstract
Free-living amoebae in water are hosts to many bacterial species living in such an environment. Such an association enables bacteria to select virulence factors and survive in adverse conditions. Waterborne mycobacteria (WBM) are important sources of community- and hospital-acquired outbreaks of nontuberculosis mycobacterial infections. However, the interactions between WBM and free-living amoebae in water have been demonstrated for only few Mycobacterium spp. We investigated the ability of a number (n = 26) of Mycobacterium spp. to survive in the trophozoites and cysts of Acanthamoeba polyphaga. All the species tested entered the trophozoites of A. polyphaga and survived at this location over a period of 5 days. Moreover, all Mycobacterium spp. survived inside cysts for a period of 15 days. Intracellular Mycobacterium spp. within amoeba cysts survived when exposed to free chlorine (15 mg/liter) for 24 h. These data document the interactions between free-living amoebae and the majority of waterborne Mycobacterium spp. Further studies are required to examine the effects of various germicidal agents on the survival of WBM in an aquatic environment.
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Affiliation(s)
- Toïdi Adékambi
- Unité des Rickettsies, Faculté de Médecine, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France
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Abstract
Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment and is well recognized to produce serious human infections, including a blinding keratitis and a fatal encephalitis. This review presents our current understanding of the burden of Acanthamoeba infections on human health, their pathogenesis and pathophysiology, and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be targets for therapeutic interventions and/or the development of preventative measures.
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Affiliation(s)
- Naveed Ahmed Khan
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London, UK.
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Whan L, Grant IR, Rowe MT. Interaction between Mycobacterium avium subsp. paratuberculosis and environmental protozoa. BMC Microbiol 2006; 6:63. [PMID: 16839422 PMCID: PMC1534044 DOI: 10.1186/1471-2180-6-63] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Accepted: 07/13/2006] [Indexed: 12/04/2022] Open
Abstract
Background Interactions between Mycobacterium avium subsp. paratuberculosis (Map) and free-living protozoa in water are likely to occur in nature. The potential impact of ingestion of Map by two naturally occurring Acanthamoeba spp. on this pathogen's survival and chlorine resistance was investigated. Results Between 4.6 and 9.1% of spiked populations of three Map strains (NCTC 8578, B2 and ATCC 19698), which had been added at a multiplicity of infection of 10:1, were ingested by Acanthamoeba castellanii CCAP 1501/1B and A. polyphaga CCAP 1501/3B during co-culture for 3 h at 25°C. Map cells were observed to be present within the vacuoles of the amoebae by acid-fast staining. During extended co-culture of Map NCTC 8578 at 25°C for 24 d with both A. castellanii and A. polyphaga Map numbers did not change significantly during the first 7 days of incubation, however a 1–1.5 log10 increase in Map numbers was observed between days 7 and 24 within both Acanthamoeba spp. Ingested Map cells were shown to be more resistant to chlorine inactivation than free Map. Exposure to 2 μg/ml chlorine for 30 min resulted in a log10 reduction of 0.94 in ingested Map but a log10 reduction of 1.73 in free Map (p < 0.001). Conclusion This study demonstrated that ingestion of Map by and survival and multiplication of Map within Acanthamoeba spp. is possible, and that Map cells ingested by amoebae are more resistant to inactivation by chlorine than free Map cells. These findings have implications with respect to the efficacy of chlorination applied to Map infected surface waters.
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Affiliation(s)
- Lynne Whan
- Department of Food Science, Queen's University Belfast, Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK
| | - Irene R Grant
- Department of Food Science, Queen's University Belfast, Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK
| | - Michael T Rowe
- Department of Food Science, Queen's University Belfast, Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK
- Food Microbiology Branch, Agriculture, Food and Environmental Science Division, Agri-Food and Biosciences Institute, Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK
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Abstract
The control of healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) infection is of concern worldwide. Given the evidence that several pathogenic species replicate within amoebae and emerge more virulent and more resistant and the abundance of amoebae in healthcare settings, we investigated interactions of Acanthamoeba polyphaga with epidemic MRSA isolates. MRSA proliferated in the presence of amoebae, attributable partly to intracellular replication. Following 24 h of co-culture, confocal microscopy revealed that c. 50% amoebae had viable MRSA within phago-lysosomes and 2% of amoebae were heavily infected with viable cocci throughout the cytoplasm. Infection control strategies should recognize the contribution of protozoa.
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Affiliation(s)
- Sharon A Huws
- Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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Abu-Zant A, Asare R, Graham JE, Abu Kwaik Y. Role for RpoS but not RelA of Legionella pneumophila in modulation of phagosome biogenesis and adaptation to the phagosomal microenvironment. Infect Immun 2006; 74:3021-6. [PMID: 16622243 PMCID: PMC1459718 DOI: 10.1128/iai.74.5.3021-3026.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The induction of virulence traits by Legionella pneumophila at the post-exponential phase has been proposed to be triggered by the stringent response mediated by RelA, which triggers RpoS. We show that L. pneumophila rpoS but not relA is required for early intracellular survival and replication within human monocyte-derived macrophages and Acanthamoeba polyphaga. In addition, L. pneumophila rpoS but not relA is required for expression of the pore-forming activity. We provide evidence that RpoS plays a role in the modulation of phagosome biogenesis and in adaptation to the phagosomal microenvironment. Thus, there is no functional link between the stringent response and RpoS in the pathogenesis of L. pneumophila.
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Affiliation(s)
- Alaeddin Abu-Zant
- Department of Microbiology, University of Louisville College of Medicine, Louisville, KY 40292, USA
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Miyake M, Fukui T, Imai Y. Differences in protein synthesis between wild type and intracellular growth-deficient strains of Legionella pneumophila in U937 and Acanthamoeba polyphaga. Microb Pathog 2006; 40:161-70. [PMID: 16488572 DOI: 10.1016/j.micpath.2005.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 12/13/2005] [Indexed: 12/28/2022]
Abstract
An important aspect of Legionnaires' disease is the growth of the causative agent, Legionella pneumophila, within infected host cells. Many proteins including stress proteins of L. pneumophila were strongly induced in a wild type strain that had been used to infect U937 human macrophage-like cells. In contrast, the expression of the proteins was much weaker within a protozoan host, Acanthamoeba polyphaga. The results suggested that active bacterial protein synthesis is required more within macrophages than within protozoa for adaptation of L. pneumophila to intracellular environments. The synthesis of these proteins was not observed in intracellular growth-deficient strains after infection in either type of host cells. The inability of protein synthesis in these strains is correlated with their inability of intracellular growth. Furthermore, on U937 infection, the synthesis of beta-galactosidase encoded in an inducible reporter construct immediately ceased in the in intracellular growth-deficient strains after infection, while the wild type strain was able to synthesize it during the course of infection. These results suggested that the intracellular growth of Legionella pneumophila within macrophages requires active protein synthesis from an earlier stage of bacterial infection.
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Affiliation(s)
- Masaki Miyake
- Department of Microbiology and COE Program in the 21st Century, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka-shi, Shizuoka 422-8526, Japan.
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Li QX, Jiang QW, Chen HY, Shen J, Chen Z, Shao YQ, Tan JD, Li ZH. [Study on the growth of Vibrio cholerae O139 within Acanthamoeba polyphaga and its survival in the cysts in low temperature]. Zhonghua Liu Xing Bing Xue Za Zhi 2006; 27:339-42. [PMID: 16875540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE To determine whether Acanthamoeba polyphaga could affect the survival and growth of Vibrio cholerae O139 in low temperature. METHODS V. cholerae O139 was co-cultured with the Acanthamoeba polyphaga to be examined on its intracellular growth and survival rate within cysts at low temperature, using methods as Gram-staining, electron microscope and passage culture. RESULTS V. cholerae O139 were observed to enter into the trophozoites and grow the within the vacuoles after 8 hour incubation with Acanthamoeba polyphaga. The germs survived in the vacuole and/or endo-layer of wall and could be re-isolated from the excystment of Acanthamoeba polyphaga. At 30 degrees C, V. cholerae O139 could survive for 120 days with the amoeba while less than 45 days in PAS. At 4 degrees C, the number of viable bacteria decreased and reached undetectable levels for both study and control groups after a 30-day incubation. V. cholerae O139 could be re-isolated from the 30-, 45-, 60- and 75-day's infected cysts after excystment. However the ability of excystment for 90-day's infected cysts decreased and V. cholerae O139 within the cyst could not be isolated again because the amoebae had lysed. CONCLUSION These findings indicated that V. cholerae O139 could grow within Acanthamoeba polyphaga and the survival time could be increased in the cysts at low temperature. It seemed that Acanthamoeba can provide an environmental reservoir for V. cholerae O139.
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Affiliation(s)
- Qin-xue Li
- School of Public Health, Fudan University, Shanghai 200032, China
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