1
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Hoque MM, Espinoza-Vergara G, McDougald D. Protozoan predation as a driver of diversity and virulence in bacterial biofilms. FEMS Microbiol Rev 2023; 47:fuad040. [PMID: 37458768 DOI: 10.1093/femsre/fuad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/19/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Protozoa are eukaryotic organisms that play a crucial role in nutrient cycling and maintaining balance in the food web. Predation, symbiosis and parasitism are three types of interactions between protozoa and bacteria. However, not all bacterial species are equally susceptible to protozoan predation as many are capable of defending against predation in numerous ways and may even establish either a symbiotic or parasitic life-style. Biofilm formation is one such mechanism by which bacteria can survive predation. Structural and chemical components of biofilms enhance resistance to predation compared to their planktonic counterparts. Predation on biofilms gives rise to phenotypic and genetic heterogeneity in prey that leads to trade-offs in virulence in other eukaryotes. Recent advances, using molecular and genomics techniques, allow us to generate new information about the interactions of protozoa and biofilms of prey bacteria. This review presents the current state of the field on impacts of protozoan predation on biofilms. We provide an overview of newly gathered insights into (i) molecular mechanisms of predation resistance in biofilms, (ii) phenotypic and genetic diversification of prey bacteria, and (iii) evolution of virulence as a consequence of protozoan predation on biofilms.
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Affiliation(s)
- M Mozammel Hoque
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Gustavo Espinoza-Vergara
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Diane McDougald
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
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2
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Campbell JA, Cianciotto NP. Legionella pneumophila Cas2 Promotes the Expression of Small Heat Shock Protein C2 That Is Required for Thermal Tolerance and Optimal Intracellular Infection. Infect Immun 2022; 90:e0036922. [PMID: 36073935 PMCID: PMC9584283 DOI: 10.1128/iai.00369-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
Previously, we demonstrated that Cas2 encoded within the CRISPR-Cas locus of Legionella pneumophila strain 130b promotes the ability of the Legionella pathogen to infect amoebal hosts. Given that L. pneumophila Cas2 has RNase activity, we posited that the cytoplasmic protein is regulating the expression of another Legionella gene(s) that fosters intracellular infection. Proteomics revealed 10 proteins at diminished levels in the cas2 mutant, and reverse transcription-quantitative (qRT-PCR) confirmed the reduced expression of a gene encoding putative small heat shock protein C2 (HspC2), among several others. As predicted, the gene was expressed more highly at 37°C to 50°C than that at 30°C, and an hspC2 mutant, but not its complemented derivative, displayed ~100-fold reduced CFU following heat shock at 55°C. Compatible with the effect of Cas2 on hspC2 expression, strains lacking Cas2 also had impaired thermal tolerance. The hspC2 mutant, like the cas2 mutant before it, was greatly impaired for infection of Acanthamoeba castellanii, a frequent host for legionellae in waters. HspC2 and Cas2 were not required for entry into these host cells but promoted the replicative phase of intracellular infection. Finally, the hspC2 mutant exhibited an additional defect during the infection of macrophages, which are the primary host for legionellae during lung infection. In summary, hspC2 is upregulated by the presence of Cas2, and HspC2 uniquely promotes both L. pneumophila extracellular survival at high temperatures and infection of amoebal and human host cells. To our knowledge, these findings also represent the first genetic proof linking Cas2 to thermotolerance, expanding the repertoire of noncanonical functions associated with CRISPR-Cas proteins.
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Affiliation(s)
- Jackson A. Campbell
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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3
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Dey R, Mameri MR, Trajkovic-Bodennec S, Bodennec J, Pernin P. Impact of inter-amoebic phagocytosis on the L. pneumophila growth. FEMS Microbiol Lett 2020; 367:5899054. [PMID: 32860684 DOI: 10.1093/femsle/fnaa147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2020] [Indexed: 01/21/2023] Open
Abstract
Free-living amoebae are known to act as replication niches for the pathogenic bacterium Legionella pneumophila in freshwater environments. However, we previously reported that some strains of the Willaertia magna species are more resistant to L. pneumophila infection and differ in their ability to support its growth. From this observation, we hypothesize that L. pneumophila growth in environment could be partly dependent on the composition of amoebic populations and on the possible interactions between different amoebic species. We tested this hypothesis by studying the growth of L. pneumophila and of a permissive free-living amoeba, Vermamoeba vermiformis (formerly named Hartmannella vermiformis), in co-culture with or without other free-living amoebae (Acanthamoeba castellanii and W. magna). We demonstrate the occurrence of inter-amoebic phagocytosis with A. castellanii and W. magna being able to ingest V. vermiformis infected or not infected with L. pneumophila. We also found that L. pneumophila growth is strongly impacted by the permissiveness of each interactive amoeba demonstrating that L. pneumophila proliferation and spread are controlled, at least in part, by inter-amoebic interactions.
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Affiliation(s)
- Rafik Dey
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France.,School of public health. University of Alberta, Edmonton AB, Canada
| | - Mouh Rayane Mameri
- Amoeba R & D Center, 38 Av des Frères Montgolfier, Chassieu F-69680, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France
| | | | - Jacques Bodennec
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1, Lyon Neuroscience Research Center CNRS, UMR 5292, Villeurbanne, F-69622, France.,Université Lyon 1, INSERM, U1028, Tiger Team, Bron, F-69500, France
| | - Pierre Pernin
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France
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4
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Li P, Vassiliadis D, Ong SY, Bennett-Wood V, Sugimoto C, Yamagishi J, Hartland EL, Pasricha S. Legionella pneumophila Infection Rewires the Acanthamoeba castellanii Transcriptome, Highlighting a Class of Sirtuin Genes. Front Cell Infect Microbiol 2020; 10:428. [PMID: 32974218 PMCID: PMC7468528 DOI: 10.3389/fcimb.2020.00428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
Legionella pneumophila is an environmental bacterium that has evolved to survive predation by soil and water amoebae such as Acanthamoeba castellanii, and this has inadvertently led to the ability of L. pneumophila to survive and replicate in human cells. L. pneumophila causes Legionnaire's Disease, with human exposure occurring via the inhalation of water aerosols containing both amoebae and the bacteria. These aerosols originate from aquatic biofilms found in artifical water sources, such as air-conditioning cooling towers and humidifiers. In these man-made environments, A. castellanii supports L. pneumophila intracellular replication, thereby promoting persistence and dissemination of the bacteria and providing protection from external stress. Despite this close evolutionary relationship, very little is known about how A. castellanii responds to L. pneumophila infection. In this study, we examined the global transcriptional response of A. castellanii to L. pneumophila infection. We compared A. castellanii infected with wild type L. pneumophila to A. castellanii infected with an isogenic ΔdotA mutant strain, which is unable to replicate intracellularly. We showed that A. castellanii underwent clear morphological and transcriptional rewiring over the course of L. pneumophila infection. Through improved annotation of the A. castellanii genome, we determined that these transcriptional changes primarily involved biological processes utilizing small GTPases, including cellular transport, signaling, metabolism and replication. In addition, a number of sirtuin-encoding genes in A. castellanii were found to be conserved and upregulated during L. pneumophila infection. Silencing of sirtuin gene, sir6f (ACA1_153540) resulted in the inhibition of A. castellanii cell proliferation during infection and reduced L. pneumophila replication. Overall our findings identified several biological pathways in amoebae that may support L. pneumophila replication and A. castellanii proliferation in environmental conditions.
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Affiliation(s)
- Pengfei Li
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Dane Vassiliadis
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Sze Ying Ong
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Vicki Bennett-Wood
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Chihiro Sugimoto
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Junya Yamagishi
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Elizabeth L Hartland
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Shivani Pasricha
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
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5
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Mameri RM, Bodennec J, Bezin L, Demanèche S. Mitigation of Expression of Virulence Genes in Legionella pneumophila Internalized in the Free-Living Amoeba Willaertia magna C2c Maky. Pathogens 2020; 9:pathogens9060447. [PMID: 32517040 PMCID: PMC7350332 DOI: 10.3390/pathogens9060447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/11/2022] Open
Abstract
Legionella pneumophila is a human pathogen responsible for a severe form of pneumonia named Legionnaire disease. Its natural habitat is aquatic environments, being in a free state or intracellular parasites of free-living amoebae, such as Acanthamoeba castellanii. This pathogen is able to replicate within some amoebae. Willaertia magna C2c Maky, a non-pathogenic amoeba, was previously demonstrated to resist to L. pneumophila and even to be able to eliminate the L. pneumophila strains Philadelphia, Lens, and Paris. Here, we studied the induction of seven virulence genes of three L. pneumophila strains (Paris, Philadelphia, and Lens) within W. magna C2c Maky in comparison within A. castellanii and with the gene expression level of L. pneumophila strains alone used as controls. We defined a gene expression-based virulence index to compare easily and without bias the transcript levels in different conditions and demonstrated that W. magna C2c Maky did not increase the virulence of L. pneumophila strains in contrast to A. castellanii. These results confirmed the non-permissiveness of W. magna C2c Maky toward L. pneumophila strains.
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Affiliation(s)
| | - Jacques Bodennec
- Lyon Neuroscience Research Center CRNL UMR5292 U1028, University of Lyon, Univ Lyon 1, CNRS, Inserm, 69500 Bron, France; (J.B.); (L.B.)
| | - Laurent Bezin
- Lyon Neuroscience Research Center CRNL UMR5292 U1028, University of Lyon, Univ Lyon 1, CNRS, Inserm, 69500 Bron, France; (J.B.); (L.B.)
| | - Sandrine Demanèche
- R&D Department, Amoéba, 69680 Chassieu, France;
- Correspondence: ; Tel.: +33-(04)-2669-1600
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6
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Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease. Genome Biol 2015; 15:505. [PMID: 25370836 DOI: 10.1186/preaccept-1086350395137407] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The genus Legionella comprises over 60 species. However, L. pneumophila and L. longbeachae alone cause over 95% of Legionnaires’ disease. To identify the genetic bases underlying the different capacities to cause disease we sequenced and compared the genomes of L. micdadei, L. hackeliae and L. fallonii (LLAP10), which are all rarely isolated from humans. RESULTS We show that these Legionella species possess different virulence capacities in amoeba and macrophages, correlating with their occurrence in humans. Our comparative analysis of 11 Legionella genomes belonging to five species reveals highly heterogeneous genome content with over 60% representing species-specific genes; these comprise a complete prophage in L. micdadei, the first ever identified in a Legionella genome. Mobile elements are abundant in Legionella genomes; many encode type IV secretion systems for conjugative transfer, pointing to their importance for adaptation of the genus. The Dot/Icm secretion system is conserved, although the core set of substrates is small, as only 24 out of over 300 described Dot/Icm effector genes are present in all Legionella species. We also identified new eukaryotic motifs including thaumatin, synaptobrevin or clathrin/coatomer adaptine like domains. CONCLUSIONS Legionella genomes are highly dynamic due to a large mobilome mainly comprising type IV secretion systems, while a minority of core substrates is shared among the diverse species. Eukaryotic like proteins and motifs remain a hallmark of the genus Legionella. Key factors such as proteins involved in oxygen binding, iron storage, host membrane transport and certain Dot/Icm substrates are specific features of disease-related strains.
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7
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Rapid and specific SPRi detection of L. pneumophila in complex environmental water samples. Anal Bioanal Chem 2015; 407:5541-5. [DOI: 10.1007/s00216-015-8726-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 03/13/2015] [Accepted: 04/17/2015] [Indexed: 10/23/2022]
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8
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Mercante JW, Winchell JM. Current and emerging Legionella diagnostics for laboratory and outbreak investigations. Clin Microbiol Rev 2015; 28:95-133. [PMID: 25567224 PMCID: PMC4284297 DOI: 10.1128/cmr.00029-14] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Legionnaires' disease (LD) is an often severe and potentially fatal form of bacterial pneumonia caused by an extensive list of Legionella species. These ubiquitous freshwater and soil inhabitants cause human respiratory disease when amplified in man-made water or cooling systems and their aerosols expose a susceptible population. Treatment of sporadic cases and rapid control of LD outbreaks benefit from swift diagnosis in concert with discriminatory bacterial typing for immediate epidemiological responses. Traditional culture and serology were instrumental in describing disease incidence early in its history; currently, diagnosis of LD relies almost solely on the urinary antigen test, which captures only the dominant species and serogroup, Legionella pneumophila serogroup 1 (Lp1). This has created a diagnostic "blind spot" for LD caused by non-Lp1 strains. This review focuses on historic, current, and emerging technologies that hold promise for increasing LD diagnostic efficiency and detection rates as part of a coherent testing regimen. The importance of cooperation between epidemiologists and laboratorians for a rapid outbreak response is also illustrated in field investigations conducted by the CDC with state and local authorities. Finally, challenges facing health care professionals, building managers, and the public health community in combating LD are highlighted, and potential solutions are discussed.
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Affiliation(s)
- Jeffrey W Mercante
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jonas M Winchell
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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9
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Gomez-Valero L, Rusniok C, Rolando M, Neou M, Dervins-Ravault D, Demirtas J, Rouy Z, Moore RJ, Chen H, Petty NK, Jarraud S, Etienne J, Steinert M, Heuner K, Gribaldo S, Médigue C, Glöckner G, Hartland EL, Buchrieser C. Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires’ disease. Genome Biol 2014. [PMID: 25370836 PMCID: PMC4256840 DOI: 10.1186/s13059-014-0505-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background The genus Legionella comprises over 60 species. However, L. pneumophila and L. longbeachae alone cause over 95% of Legionnaires’ disease. To identify the genetic bases underlying the different capacities to cause disease we sequenced and compared the genomes of L. micdadei, L. hackeliae and L. fallonii (LLAP10), which are all rarely isolated from humans. Results We show that these Legionella species possess different virulence capacities in amoeba and macrophages, correlating with their occurrence in humans. Our comparative analysis of 11 Legionella genomes belonging to five species reveals highly heterogeneous genome content with over 60% representing species-specific genes; these comprise a complete prophage in L. micdadei, the first ever identified in a Legionella genome. Mobile elements are abundant in Legionella genomes; many encode type IV secretion systems for conjugative transfer, pointing to their importance for adaptation of the genus. The Dot/Icm secretion system is conserved, although the core set of substrates is small, as only 24 out of over 300 described Dot/Icm effector genes are present in all Legionella species. We also identified new eukaryotic motifs including thaumatin, synaptobrevin or clathrin/coatomer adaptine like domains. Conclusions Legionella genomes are highly dynamic due to a large mobilome mainly comprising type IV secretion systems, while a minority of core substrates is shared among the diverse species. Eukaryotic like proteins and motifs remain a hallmark of the genus Legionella. Key factors such as proteins involved in oxygen binding, iron storage, host membrane transport and certain Dot/Icm substrates are specific features of disease-related strains. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0505-0) contains supplementary material, which is available to authorized users.
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10
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Denoncourt AM, Paquet VE, Charette SJ. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria. Front Microbiol 2014; 5:240. [PMID: 24904553 PMCID: PMC4033053 DOI: 10.3389/fmicb.2014.00240] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.
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Affiliation(s)
- Alix M Denoncourt
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval Quebec City, QC, Canada
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11
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Bigot R, Bertaux J, Frere J, Berjeaud JM. Intra-amoeba multiplication induces chemotaxis and biofilm colonization and formation for Legionella. PLoS One 2013; 8:e77875. [PMID: 24205008 PMCID: PMC3812023 DOI: 10.1371/journal.pone.0077875] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 09/13/2013] [Indexed: 11/19/2022] Open
Abstract
Legionella pneumophila, a facultative intracellular bacterium, is the causative agent of legionellosis. In the environment this pathogenic bacterium colonizes the biofilms as well as amoebae, which provide a rich environment for the replication of Legionella. When seeded on pre-formed biofilms, L. pneumophila was able to establish and survive and was only found at the surface of the biofilms. Different phenotypes were observed when the L. pneumophila, used to implement pre-formed biofilms or to form mono-species biofilms, were cultivated in a laboratory culture broth or had grown intracellulary within the amoeba. Indeed, the bacteria, which developed within the amoeba, formed clusters when deposited on a solid surface. Moreover, our results demonstrate that multiplication inside the amoeba increased the capacity of L. pneumophila to produce polysaccharides and therefore enhanced its capacity to establish biofilms. Finally, it was shown that the clusters formed by L. pneumophila were probably related to the secretion of a chemotaxis molecular agent.
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Affiliation(s)
- Renaud Bigot
- Equipe Microbiologie de l’Eau, Ecologie & Biologie des Interactions, Centre national de la recherche scientifique UMR 7267, Université de Poitiers, Poitiers, France
| | - Joanne Bertaux
- Equipe Ecologie Evolution Symbiose, Ecologie and Biologie des Interactions, Centre national de la recherche scientifique UMR 7267, Université de Poitiers, Poitiers, France
| | - Jacques Frere
- Equipe Microbiologie de l’Eau, Ecologie & Biologie des Interactions, Centre national de la recherche scientifique UMR 7267, Université de Poitiers, Poitiers, France
| | - Jean-Marc Berjeaud
- Equipe Microbiologie de l’Eau, Ecologie & Biologie des Interactions, Centre national de la recherche scientifique UMR 7267, Université de Poitiers, Poitiers, France
- * E-mail:
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12
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Chaabna Z, Forey F, Reyrolle M, Jarraud S, Atlan D, Fontvieille D, Gilbert C. Molecular diversity and high virulence of Legionella pneumophila strains isolated from biofilms developed within a warm spring of a thermal spa. BMC Microbiol 2013; 13:17. [PMID: 23350929 PMCID: PMC3564684 DOI: 10.1186/1471-2180-13-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/14/2013] [Indexed: 01/13/2023] Open
Abstract
Background Several cases of legionellosis have been diagnosed in the same French thermal spa in 1986, 1994 and 1997. L. pneumophila serogroup 1 (Lp1) strains have been isolated from several patients, but the source of contamination was not identified despite the presence of different Lp1 in water samples of the three natural springs feeding the spa at this period. Results Our strategy was to investigate L. pneumophila (Lp) strains from natural biofilms developed in a sulphur-rich warm spring of this contaminated site. Biofilm analysis revealed the presence of three Lp serogroups (Lp1, Lp10 and Lp12). Surprisingly, Lp10 and Lp12 were not reported in the previous described studies from water samples. Besides, the new seven Lp1 we isolated exhibit a high molecular diversity and have been differentiated in five classes according to their DNA genome patterns obtained by PFGE and mip sequences. It must be noted that these DNA patterns are original and unknown in databases. Interestingly, the 27 Lp environmental strains we isolated display a higher cytotoxicity and virulence towards the amoeba Acanthamoeba castellanii than those of known Lp1 epidemic strains. Conclusion The characteristics of Legionella pneumophila Lp1 strains isolated from the warm spring are in agreement with their presence in biofilms and their probable long-term persistence in this ecosystem.
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Affiliation(s)
- Zineddine Chaabna
- UMR CARRTEL, Université de Savoie-INRA, Le Bourget du Lac F-73376, France
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13
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Joshi AD, Swanson MS. Secrets of a successful pathogen: legionella resistance to progression along the autophagic pathway. Front Microbiol 2011; 2:138. [PMID: 21743811 PMCID: PMC3127087 DOI: 10.3389/fmicb.2011.00138] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 06/13/2011] [Indexed: 11/22/2022] Open
Abstract
To proliferate within phagocytes, Legionella pneumophila relies on Type IV secretion to modulate host cellular pathways. Autophagy is an evolutionarily conserved degradative pathway that captures and transfers a variety of microbes to lysosomes. Biogenesis of L. pneumophila-containing vacuoles and autophagosomes share several features, including endoplasmic reticulum (ER)-derived membranes, contributions by the host GTPases Rab1, Arf1 and Sar1, and a final destiny in lysosomes. We discuss morphological, molecular genetic, and immunological data that support the model that, although A/J mouse macrophages efficiently engulf L. pneumophila within autophagosomal membranes, the Type IV effector proteins DrrA/SidM, LidA, and RalF prolong association with the ER. By inhibiting immediately delivery to lysosomes, the bacteria persist in immature autophagosomal vacuoles for a period sufficient to differentiate into an acid-resistant, replicative form. Subsequent secretion of the Type IV effector LepB releases the block to autophagosome maturation, and the adapted progeny continue to replicate within autophagolysosomes. Accordingly, L. pneumophila can be exploited as a genetic tool to analyze the recruitment and function of the macrophage autophagy pathway.
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Affiliation(s)
- Amrita D Joshi
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
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14
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Thomas JM, Ashbolt NJ. Do free-living amoebae in treated drinking water systems present an emerging health risk? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:860-9. [PMID: 21194220 DOI: 10.1021/es102876y] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
There is an expanding body of evidence that free-living amoebae (FLA) increase both the numbers and virulence of water-based, human-pathogenic, amoeba-resisting microorganisms (ARM). Legionella spp., Mycobacterium spp., and other opportunistic human pathogens are known to be both ARM and also the etiologic agents of potentially fatal human lung infections. However, comparatively little is known about the FLA that may facilitate ARM growth in drinking water. This review examines the available literature on FLA in treated drinking water systems; in total 26 studies from 18 different countries. FLA were reported to breakthrough the water treatment barrier and enter distribution systems, in addition to the expected post-treatment system ingress. Once in the distribution system there is evidence of FLA colonization and regrowth especially in reservoirs and in-premise plumbing storage tanks. At the point of use the average FLA detection rate was 45% but highly variable (n = 16, σ = 31) due to both differences in both assay methods and the type of water systems examined. This review reveals that FLA are consistently detected in treated drinking water systems around the world and present a yet unquantified emerging health risk. However, more research is urgently required before accurate risks assessments can be undertaken to assess the impacts on human health, in households and institutions, due to exposure to FLA facilitated pathogenic ARM.
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Affiliation(s)
- Jacqueline M Thomas
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW 2052 Australia.
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Lau HY, Ashbolt NJ. The role of biofilms and protozoa in Legionella pathogenesis: implications for drinking water. J Appl Microbiol 2009; 107:368-78. [PMID: 19302312 DOI: 10.1111/j.1365-2672.2009.04208.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Current models to study Legionella pathogenesis include the use of primary macrophages and monocyte cell lines, various free-living protozoan species and murine models of pneumonia. However, there are very few studies of Legionella spp. pathogenesis aimed at associating the role of biofilm colonization and parasitization of biofilm microbiota and release of virulent bacterial cell/vacuoles in drinking water distribution systems. Moreover, the implications of these environmental niches for drinking water exposure to pathogenic legionellae are poorly understood. This review summarizes the known mechanisms of Legionella spp. proliferation within Acanthamoeba and mammalian cells and advocates the use of the amoeba model to study Legionella pathogenicity because of their close association with Legionella spp. in the aquatic environment. The putative role of biofilms and amoebae in the proliferation, development and dissemination of potentially pathogenic Legionella spp. is also discussed. Elucidating the mechanisms of Legionella pathogenicity development in our drinking water systems will aid in elimination strategies and procedural designs for drinking water systems and in controlling exposure to Legionella spp. and similar pathogens.
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Affiliation(s)
- H Y Lau
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
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Williams RSB, Boeckeler K, Gräf R, Müller-Taubenberger A, Li Z, Isberg RR, Wessels D, Soll DR, Alexander H, Alexander S. Towards a molecular understanding of human diseases using Dictyostelium discoideum. Trends Mol Med 2006; 12:415-24. [PMID: 16890490 DOI: 10.1016/j.molmed.2006.07.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 06/23/2006] [Accepted: 07/21/2006] [Indexed: 12/29/2022]
Abstract
The social amoeba Dictyostelium discoideum is increasingly being used as a simple model for the investigation of problems that are relevant to human health. This article focuses on several recent examples of Dictyostelium-based biomedical research, including the analysis of immune-cell disease and chemotaxis, centrosomal abnormalities and lissencephaly, bacterial intracellular pathogenesis, and mechanisms of neuroprotective and anti-cancer drug action. The combination of cellular, genetic and molecular biology techniques that are available in Dictyostelium often makes the analysis of these problems more amenable to study in this system than in mammalian cell culture. Findings that have been made in these areas using Dictyostelium have driven research in mammalian systems and have established Dictyostelium as a powerful model for human-disease analysis.
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Affiliation(s)
- Robin S B Williams
- Department of Biology and the Wolfson Institute for Biomedical Research, University College London, London, WC1E 6BT, UK.
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Piao Z, Sze CC, Barysheva O, Iida KI, Yoshida SI. Temperature-regulated formation of mycelial mat-like biofilms by Legionella pneumophila. Appl Environ Microbiol 2006; 72:1613-22. [PMID: 16461717 PMCID: PMC1392928 DOI: 10.1128/aem.72.2.1613-1622.2006] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Fifty strains representing 38 species of the genus Legionella were examined for biofilm formation on glass, polystyrene, and polypropylene surfaces in static cultures at 25 degrees C, 37 degrees C, and 42 degrees C. Strains of Legionella pneumophila, the most common causative agent of Legionnaires' disease, were found to have the highest ability to form biofilms among the test strains. The quantity, rate of formation, and adherence stability of L. pneumophila biofilms showed considerable dependence on both temperature and surface material. Glass and polystyrene surfaces gave between two- to sevenfold-higher yields of biofilms at 37 degrees C or 42 degrees C than at 25 degrees C; conversely, polypropylene surface had between 2 to 16 times higher yields at 25 degrees C than at 37 degrees C or 42 degrees C. On glass surfaces, the biofilms were formed faster but attached less stably at 37 degrees C or 42 degrees C than at 25 degrees C. Both scanning electron microscopy and confocal laser scanning microscopy revealed that biofilms formed at 37 degrees C or 42 degrees C were mycelial mat like and were composed of filamentous cells, while at 25 degrees C, cells were rod shaped. Planktonic cells outside of biofilms or in shaken liquid cultures were rod shaped. Notably, the filamentous cells were found to be multinucleate and lacking septa, but a recA null mutant of L. pneumophila was unaffected in its temperature-regulated filamentation within biofilms. Our data also showed that filamentous cells were able to rapidly give rise to a large number of short rods in a fresh liquid culture at 37 degrees C. The possibility of this biofilm to represent a novel strategy by L. pneumophila to compete for proliferation among the environmental microbiota is discussed.
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Affiliation(s)
- Zhenyu Piao
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Affiliation(s)
- Jacqueline Dawn Parry
- Department of Biological Sciences, The Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
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Abstract
Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease.
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Affiliation(s)
- Francine Marciano-Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA.
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Steinert M, Flügel M, Schuppler M, Helbig JH, Supriyono A, Proksch P, Lück PC. The Lly protein is essential for p-hydroxyphenylpyruvate dioxygenase activity in Legionella pneumophila. FEMS Microbiol Lett 2001; 203:41-7. [PMID: 11557138 DOI: 10.1111/j.1574-6968.2001.tb10818.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The lly locus confers fluorescence, haemolysis, brown pigmentation and an increased resistance to light in Legionella pneumophila. In this study, we correlated the pigment production of two lly-positive L. pneumophila isolates and a recombinant lly-positive Escherichia coli strain with the presence of homogentisic acid (HGA) in the culture supernatant. The detection of HGA by high performance liquid chromatography and the data analysis of the deduced amino acid sequence of the lly gene indicate that the lly locus codes for a p-hydroxyphenylpyruvate dioxygenase (HPPD). This enzyme catalyses the transformation of p-hydroxyphenylpyruvate into HGA, which subsequently oxidises and polymerises into a melanin-like pigment. One open reading frame (ORF 1) in the lly region exhibited homologies with genes of Synechocystis sp., Petroselium crispum and Streptomyces mycarofaciens that code for methyltransferases. By screening a genomic library of L. pneumophila (serogroup 1) strain Corby with a monoclonal antibody against the legiolysin (lly), we identified two recombinant E. coli clones that did not produce the brown pigment and showed no haemolysis and fluorescence. DNA sequencing revealed that both clones contained 874 nucleotides of the N-terminal part of the lly gene. The recombinant strains expressed truncated legiolysin proteins of 39.5 and 35.7 kDa and did not produce HGA. Considering the highly conserved structure of legiolysin-like HPPD genes from other organisms, we suggest that the C-terminus of the legiolysin may be essential for the enzymatic activity that conferred pigmentation via HGA polymerisation, haemolysis and fluorescence.
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Affiliation(s)
- M Steinert
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Röntgenring 11, D-97070 Würzburg, Germany.
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Abstract
Free-living amoebae are a diverse group of ubiquitous unicellular organisms, some of which cause severe central nervous system infections and keratitis. However, the focus of research has shifted from the direct pathogenic effects of free-living amoebae towards their role as carriers of pathogenic bacteria. Large outbreaks of legionellosis with numerous fatal cases, both in hospitals and in the community, appear to be the visible tip of the iceberg of complex relationships between amoebae and bacteria in biofilms. The recognition of amoebae as reservoirs and vehicles for bacterial spread leads us to public health issues such as the development of pathogenicity, antibiotic resistance, quality of public water supplies, housing standards, sanitation and decontamination measures. In this review we discuss bacterial infections of free-living amoebae from both a "biological" and general "infection control" point of view.
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Affiliation(s)
- J Winiecka-Krusnell
- Swedish Institute for Infectious Disease Control, Parasitology Department, Solna, Sweden.
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Flieger A, Gong S, Faigle M, Stevanovic S, Cianciotto NP, Neumeister B. Novel lysophospholipase A secreted by Legionella pneumophila. J Bacteriol 2001; 183:2121-4. [PMID: 11222614 PMCID: PMC95111 DOI: 10.1128/jb.183.6.2121-2124.2001] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We show that Legionella pneumophila possesses lysophospholipase A activity, which releases fatty acids from lysophosphatidylcholine. The NH2-terminal sequence of the enzyme contained FGDSLS, corresponding to a catalytic domain in a recently described group of lipolytic enzymes. Culture supernatants of a L. pneumophila pilD mutant lost the ability to cleave lysophosphatidylcholine.
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Affiliation(s)
- A Flieger
- Abteilung für Transfusionsmedizin, Universitätsklinikum Tübingen, Universität Tübingen, D-72076 Tübingen, Germany.
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