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Abstract
BACKGROUND Simkania negevensis is an obligate intracellular Gram-negative bacterium (family Simkaniaceae, order Chlamydiales) that has been isolated from domestic and mains water supplies, is able to infect human macrophages, and can induce an inflammatory response in the host. METHODS From June to December 2016, in a single-center observational study, colonic Crohn's disease patients and controls (subjects undergoing screening for colorectal cancer) underwent blood tests to identify serum-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) to S. negevensis and a colonoscopy with biopsies for detection of S. negevensis DNA by polymerase chain reaction (PCR). RESULTS Forty-three Crohn's disease patients and 18 controls were enrolled. Crohn's disease patients had higher prevalence of IgA antibodies to S. negevensis compared with controls (20.9% versus 0%, p = 0.04). Simkaniaceae negevensis DNA was detected in 34.9% and 5.6% of intestinal biopsies in Crohn's disease patients and controls, respectively (p = 0.02). All Crohn's disease patients with PCR-positive biopsies for S. negevensis were IgG seropositive, with specific IgA in 60% of them (p < 0.001). Immunosuppressive therapies, extraintestinal manifestations, or disease activity did not influence the presence of S. negevensis in the Crohn's disease population. CONCLUSIONS We identified S. negevensis in Crohn's disease patients by demonstrating the presence of S. negevensis mucosal DNA and seropositivity to the bacterium. These results could support the presence of an acute or persistent S. negevensis infection and suggest a possible role in the pathogenesis of Crohn's disease.
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Vouga M, Baud D, Greub G. Simkania negevensis may produce long-lasting infections in human pneumocytes and endometrial cells. Pathog Dis 2017; 75:ftw115. [PMID: 28087650 PMCID: PMC5353995 DOI: 10.1093/femspd/ftw115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2017] [Indexed: 11/26/2022] Open
Abstract
Simkania negevensis is a novel Chlamydia-related bacterium and the founding member of the Simkaniaceae family within the Chlamydiales order. Little is known about the biology and pathogenesis of this bacterium. So far, S. negevensis has been considered as an amoebal symbiont, but its natural host remains unknown. Moreover, evidence of human exposition has been reported worldwide and an association with pneumonia and bronchiolitis is suspected. Here, we evaluated the ability of S. negevensis to replicate in potential environmental reservoirs, namely amoebae and arthropods, as well as in mammalian cells (Vero cells, pneumocytes and endometrial cells) and further evaluated the characteristics of its replicative vacuole. We demonstrated that S. negevensis efficiently replicates in all cell lines tested, with the shortest doubling time and an increased adhesion observed in pneumocytes. Our work highlights the specificities of the Simkania-containing vacuole compared to other Chlamydiales; contrarily to Chlamydia trachomatis, S. negevensis does not disrupt the Golgi apparatus. Importantly, our work suggests that S. negevensis infection is associated with few cytopathic effects and might persist for a prolonged time in infected cells. Further evaluation of its implication in human diseases is required; an implication in chronic or subacute respiratory infections might be suspected.
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Affiliation(s)
- Manon Vouga
- Materno-fetal and Obstetrics Research Unit, Department 'Femme-Mère-Enfant', Maternity, University Hospital, 1011 Lausanne, Switzerland.,Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, 1011 Lausanne, Switzerland
| | - David Baud
- Materno-fetal and Obstetrics Research Unit, Department 'Femme-Mère-Enfant', Maternity, University Hospital, 1011 Lausanne, Switzerland
| | - Gilbert Greub
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, 1011 Lausanne, Switzerland.,Infectious Disease Service, University Hospital, 1011 Lausanne, Switzerland
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3
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Angeletti A, Biondi R, Battaglino G, Cremonini E, Comai G, Capelli I, Donati G, Cevenini R, Donati M, La Manna G. Seroprevalence of a "new" bacterium, Simkania negevensis, in renal transplant recipients and in hemodialysis patients. BMC Nephrol 2017; 18:133. [PMID: 28407799 PMCID: PMC5391609 DOI: 10.1186/s12882-017-0548-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/16/2017] [Indexed: 01/09/2023] Open
Abstract
Background Simkania negevensis is an obligate intracellular bacterium belonging to the family Simkaniaceae in the Chlamydiales order. It is considered an ubiquitous microorganism and aquatic environments may be involved as a source of infection for humans. It was just isolated in samples from domestic water supplies and from mains water supplies, like spa water or swimming pool water, confirming its ability to resist to the common chlorination treatments. Evidence indicates a possible role of the microorganism in respiratory tract infections, in gastroenteric disorders and in the pathogenesis of cardiovascular disease, furthermore it has hypothesized that it could play a role in lung transplant rejection. Prevalence and possible effects in nephrology are unknown. Methods We examined the occurrence of Simkania negevensis in two differents populations, both characterized by a high susceptibility to infectious complications: 105 hemodialysis patients, 105 renal transplant recipients and 105 healthy subjects through the IgG and IgA response to Simkania negevensis in their sera. Serum antibodies to Simkania negevensis were detected by a homemade ELISA performed according to the Kahane’s protocol. Furthermore water samples from hemodialytic circuit were collected, to evaluate Simkania negevensis resistance to usual treatment of disinfection. Results Our results were unexpected, showing a higher seroprevalence of antibodies against Simkania negevensis in the hemodialysis patients, compared to renal transplant patients (IgG 22% vs 9% - IgA 9% vs 3%). S. negevensis was isolated in all water samples analyzed. Conclusions Our study detected for the first time the occurrence of S. negevensis in hemodialysis and in renal transplant patients. Our findings suggest that water used in hemodialysis could be one of the possible sources of S. negevensis infection, without clinical involvement risk for patients.
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Affiliation(s)
- Andrea Angeletti
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy
| | - Roberta Biondi
- Microbiology, DIMES, University of Bologna, Bologna, Italy
| | - Giuseppe Battaglino
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy
| | | | - Giorgia Comai
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy
| | - Irene Capelli
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy
| | - Gabriele Donati
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy
| | | | - Manuela Donati
- Microbiology, DIMES, University of Bologna, Bologna, Italy
| | - Gaetano La Manna
- Department of Experimental, Diagnostic, Specialty Medicine, Nephrology, Dialysis, and Renal Transplant Unit, S. Orsola University Hospital, Via G. Massarenti 9, 40138, Bologna, Italy.
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Vouga M, Baud D, Greub G. Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order. Crit Rev Microbiol 2016; 43:62-80. [PMID: 27786615 DOI: 10.3109/1040841x.2016.1165650] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Simkania negevensis is a Chlamydia-related bacterium discovered in 1993 and represents the founding member of the Simkaniaceae family within the Chlamydiales order. As other Chlamydiales, it is an obligate intracellular bacterium characterized by a biphasic developmental cycle. Its similarities with the pathogenic Chlamydia trachomatis and Chlamydia pneumoniae make it an interesting bacterium. So far, little is known about its biology, but S. negevensis harbors various microbiological characteristics of interest, including a strong association of the Simkania-containing vacuole with the ER and the presence of an intron in the 23S rRNA encoding gene. Evidence of human exposition has been reported worldwide. However, there is a lack of robust clinical studies evaluating its implication in human diseases; current data suggest an association with pneumonia and bronchiolitis making S. negevensis a potential emerging pathogen. Owing to its fastidious growth requirements, the clinical relevance of S. negevensis is probably underestimated. In this review, we summarize the current knowledge on S. negevensis and explore future research challenges.
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Affiliation(s)
- Manon Vouga
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,b Department "Femme-Mère-Enfant" , Materno-Fetal and Obstetrics Research Unit, University Hospital , Lausanne , Switzerland
| | - David Baud
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,b Department "Femme-Mère-Enfant" , Materno-Fetal and Obstetrics Research Unit, University Hospital , Lausanne , Switzerland
| | - Gilbert Greub
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,c Infectious Diseases Unit , University hospital , Lausanne , Switzerland
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5
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Herweg JA, Rudel T. Interaction of Chlamydiae with human macrophages. FEBS J 2015; 283:608-18. [PMID: 26613554 DOI: 10.1111/febs.13609] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 11/13/2015] [Accepted: 11/24/2015] [Indexed: 11/28/2022]
Abstract
The phylum Chlamydiae contains several members that are well-known human pathogens, like Chlamydia trachomatis and C. pneumoniae. Establishing a chronic bacterial infection requires the active evasion of the host immune response. A major arm of the innate immune defence is constituted by macrophages, which fight infections by removing bacteria and triggering an adaptive immune response. However, some pathogenic Chlamydia infect and survive in macrophages at least for a certain period of time. Therefore, macrophages can serve as vehicles for the dissemination of bacterial infections from the primary infection site via the urogenital or respiratory tract to distant sites in the body. The capacity to infect macrophages seems to depend on the chlamydial strain and the source of macrophages. In vitro infections of macrophages with C. trachomatis, C. psittaci and C. pneumoniae reveal low efficiency of infection and progeny formation, as well as failure to develop mature inclusions. In contrast, the emerging pathogen, Simkania negevensis, actively replicates in macrophages. Here we summarize the current knowledge of the intracellular and molecular key mechanisms of C. trachomatis, C. pneumoniae and S. negevensis infections in human macrophages.
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Affiliation(s)
- Jo-Ana Herweg
- Biocenter, Department of Microbiology, University of Würzburg, Germany
| | - Thomas Rudel
- Biocenter, Department of Microbiology, University of Würzburg, Germany
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6
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Herweg JA, Pons V, Becher D, Hecker M, Krohne G, Barbier J, Berger H, Rudel T, Mehlitz A. Proteomic analysis of the Simkania-containing vacuole: the central role of retrograde transport. Mol Microbiol 2015; 99:151-71. [PMID: 26374382 DOI: 10.1111/mmi.13222] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2015] [Indexed: 01/25/2023]
Abstract
Simkania negevensis is an obligate intracellular bacterial pathogen that grows in amoeba or human cells within a membrane-bound vacuole forming endoplasmic reticulum (ER) contact sites. The membrane of this Simkania-containing vacuole (SnCV) is a critical host-pathogen interface whose origin and molecular interactions with cellular organelles remain poorly defined. We performed proteomic analysis of purified ER-SnCV-membranes using label free LC-MS(2) to define the pathogen-containing organelle composition. Of the 1,178 proteins of human and 302 proteins of Simkania origin identified by this strategy, 51 host cell proteins were enriched or depleted by infection and 57 proteins were associated with host endosomal transport pathways. Chemical inhibitors that selectively interfere with trafficking at the early endosome-to-trans-Golgi network (TGN) interface (retrograde transport) affected SnCV formation, morphology and lipid transport. Our data demonstrate that Simkania exploits early endosome-to-TGN transport for nutrient acquisition and growth.
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Affiliation(s)
- Jo-Ana Herweg
- Department of Microbiology, University of Würzburg, Biocenter, Am Hubland, D-97074, Würzburg, Germany
| | - Valérie Pons
- DSV, iBiTec-S, LabEx LERMIT, CEA, F-91191, Gif sur Yvette, France
| | - Dörte Becher
- Department of Microbial Proteomics, University of Greifswald, Institute of Microbiology, Friedrich-Ludwig-Jahn-Straße 15, D-17487, Greifswald, Germany
| | - Michael Hecker
- Microbial Physiology/Molecular Biology, University of Greifswald, Institute of Microbiology, Friedrich-Ludwig-Jahn-Straße 15, D-17487, Greifswald, Germany
| | - Georg Krohne
- Division of Electron Microscopy, University of Würzburg, Biocenter, Am Hubland, D-97074, Würzburg, Germany
| | - Julien Barbier
- DSV, iBiTec-S, LabEx LERMIT, CEA, F-91191, Gif sur Yvette, France
| | - Hilmar Berger
- Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Charitéplatz 1, D-10117, Berlin, Germany
| | - Thomas Rudel
- Department of Microbiology, University of Würzburg, Biocenter, Am Hubland, D-97074, Würzburg, Germany
| | - Adrian Mehlitz
- Department of Microbiology, University of Würzburg, Biocenter, Am Hubland, D-97074, Würzburg, Germany.,Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Charitéplatz 1, D-10117, Berlin, Germany
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7
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Herweg JA, Hansmeier N, Otto A, Geffken AC, Subbarayal P, Prusty BK, Becher D, Hensel M, Schaible UE, Rudel T, Hilbi H. Purification and proteomics of pathogen-modified vacuoles and membranes. Front Cell Infect Microbiol 2015; 5:48. [PMID: 26082896 PMCID: PMC4451638 DOI: 10.3389/fcimb.2015.00048] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/14/2015] [Indexed: 01/08/2023] Open
Abstract
Certain pathogenic bacteria adopt an intracellular lifestyle and proliferate in eukaryotic host cells. The intracellular niche protects the bacteria from cellular and humoral components of the mammalian immune system, and at the same time, allows the bacteria to gain access to otherwise restricted nutrient sources. Yet, intracellular protection and access to nutrients comes with a price, i.e., the bacteria need to overcome cell-autonomous defense mechanisms, such as the bactericidal endocytic pathway. While a few bacteria rupture the early phagosome and escape into the host cytoplasm, most intracellular pathogens form a distinct, degradation-resistant and replication-permissive membranous compartment. Intracellular bacteria that form unique pathogen vacuoles include Legionella, Mycobacterium, Chlamydia, Simkania, and Salmonella species. In order to understand the formation of these pathogen niches on a global scale and in a comprehensive and quantitative manner, an inventory of compartment-associated host factors is required. To this end, the intact pathogen compartments need to be isolated, purified and biochemically characterized. Here, we review recent progress on the isolation and purification of pathogen-modified vacuoles and membranes, as well as their proteomic characterization by mass spectrometry and different validation approaches. These studies provide the basis for further investigations on the specific mechanisms of pathogen-driven compartment formation.
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Affiliation(s)
- Jo-Ana Herweg
- Chair of Microbiology, Biocenter, University of Würzburg Würzburg, Germany
| | - Nicole Hansmeier
- Division of Microbiology, University of Osnabrück Osnabrück, Germany
| | - Andreas Otto
- Institute of Microbiology, Ernst-Moritz-Arndt University Greifswald Greifswald, Germany
| | - Anna C Geffken
- Priority Area Infections, Cellular Microbiology, Research Center Borstel, Leibniz Center for Medicine and Biosciences Borstel, Germany
| | - Prema Subbarayal
- Chair of Microbiology, Biocenter, University of Würzburg Würzburg, Germany
| | - Bhupesh K Prusty
- Chair of Microbiology, Biocenter, University of Würzburg Würzburg, Germany
| | - Dörte Becher
- Institute of Microbiology, Ernst-Moritz-Arndt University Greifswald Greifswald, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück Osnabrück, Germany
| | - Ulrich E Schaible
- Priority Area Infections, Cellular Microbiology, Research Center Borstel, Leibniz Center for Medicine and Biosciences Borstel, Germany
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg Würzburg, Germany
| | - Hubert Hilbi
- Department of Medicine, Max von Pettenkofer Institute, Ludwig-Maximilians University Munich Munich, Germany ; Department of Medicine, Institute of Medical Microbiology, University of Zürich Zürich, Switzerland
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8
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Donati M, Cremonini E, Di Francesco A, Dallolio L, Biondi R, Muthusamy R, Leoni E. Prevalence of Simkania negevensis in chlorinated water from spa swimming pools and domestic supplies. J Appl Microbiol 2015; 118:1076-82. [PMID: 25619531 DOI: 10.1111/jam.12761] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/15/2015] [Accepted: 01/15/2015] [Indexed: 11/30/2022]
Abstract
AIMS This study aimed to investigate the prevalence of Simkania negevensis in the chlorinated water of spa swimming pools and domestic network systems. METHODS AND RESULTS A total of 10 and 36 samples were collected from two domestic water supplies and four spa facilities, respectively. Simkania negevensis was isolated in Acanthamoeba castellanii monolayers and detected by Gimenez staining and immunofluorescence test. Simkania negevensis DNA, extracted from the positive samples, was confirmed by a nested PCR assay followed by sequencing. Simkania negevensis was detected in 41·3% of samples (domestic water: 50%; untreated spa supply water: 25%; chlorinated spa pool water: 42·9%) from all the examined water systems in successive samplings performed in 1 year. The presence of S. negevensis was not correlated with the counts of Heterotrophic Bacteria and Pseudomonas aeruginosa. Unlike Legionella spp., which were never isolated from the swimming-pool water samples, S. negevensis was also detected in chlorinated spa water. CONCLUSIONS This investigation shows that Simkania is widespread in natural and man-made aquatic environments, which may represent possible sources of infection: in the swimming pools, in particular, the aerosol generated by the water movement could increase the risk of inhalation of infected particles. SIGNIFICANCE AND IMPACT OF THE STUDY This study represents the first evidence of the presence of S. negevensis in spa pool water. Sero-epidemiological surveys on spa users could help to clarify its transmission in this environment.
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Affiliation(s)
- M Donati
- Unit of Microbiology, DIMES, University of Bologna, Bologna, Italy
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Taylor-Brown A, Vaughan L, Greub G, Timms P, Polkinghorne A. Twenty years of research into Chlamydia-like organisms: a revolution in our understanding of the biology and pathogenicity of members of the phylum Chlamydiae. Pathog Dis 2014; 73:1-15. [PMID: 25854000 DOI: 10.1093/femspd/ftu009] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2014] [Indexed: 11/13/2022] Open
Abstract
Chlamydiae are obligate intracellular bacteria that share a unique but remarkably conserved biphasic developmental cycle that relies on a eukaryotic host cell for survival. Although the phylum was originally thought to only contain one family, the Chlamydiaceae, a total of nine families are now recognized. These so-called Chlamydia-like organisms (CLOs) are also referred to as 'environmental chlamydiae', as many were initially isolated from environmental sources. However, these organisms are also emerging pathogens, as many, such as Parachlamydia sp., Simkania sp. and Waddlia sp., have been associated with human disease, and others, such as Piscichlamydia sp. and Parilichlamydia sp., have been documented in association with diseases in animals. Their strict intracellular nature and the requirement for cell culture have been a confounding factor in characterizing the biology and pathogenicity of CLOs. Nevertheless, the genomes of seven CLO species have now been sequenced, providing new information on their potential ability to adapt to a wide range of hosts. As new isolation and diagnostic methods advance, we are able to further explore the richness of this phylum with further research likely to help define the true pathogenic potential of the CLOs while also providing insight into the origins of the 'traditional' chlamydiae.
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Affiliation(s)
- Alyce Taylor-Brown
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Lloyd Vaughan
- Institute of Veterinary Pathology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Adam Polkinghorne
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
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10
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Mehlitz A, Karunakaran K, Herweg JA, Krohne G, van de Linde S, Rieck E, Sauer M, Rudel T. The chlamydial organism Simkania negevensis forms ER vacuole contact sites and inhibits ER-stress. Cell Microbiol 2014; 16:1224-43. [PMID: 24528559 DOI: 10.1111/cmi.12278] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/28/2014] [Accepted: 02/05/2014] [Indexed: 01/01/2023]
Abstract
Most intracellular bacterial pathogens reside within membrane-surrounded host-derived vacuoles. Few of these bacteria exploit membranes from the host's endoplasmic reticulum (ER) to form a replicative vacuole. Here, we describe the formation of ER-vacuole contact sites as part of the replicative niche of the chlamydial organism Simkania negevensis. Formation of ER-vacuole contact sites is evolutionary conserved in the distantly related protozoan host Acanthamoeba castellanii. Simkania growth is accompanied by mitochondria associating with the Simkania-containing vacuole (SCV). Super-resolution microscopy as well as 3D reconstruction from electron micrographs of serial ultra-thin sections revealed a single vacuolar system forming extensive ER-SCV contact sites on the Simkania vacuolar surface. Simkania infection induced an ER-stress response, which was later downregulated. Induction of ER-stress with Thapsigargin or Tunicamycin was strongly inhibited in cells infected with Simkania. Inhibition of ER-stress was required for inclusion formation and efficient growth, demonstrating a role of ER-stress in the control of Simkania infection. Thus, Simkania forms extensive ER-SCV contact sites in host species evolutionary as diverse as human and amoeba. Moreover, Simkania is the first bacterial pathogen described to interfere with ER-stress induced signalling to promote infection.
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Affiliation(s)
- Adrian Mehlitz
- University of Wuerzburg, Biocenter, Department of Microbiology, Am Hubland, D-97074, Wuerzburg, Germany
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11
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Omsland A, Sixt BS, Horn M, Hackstadt T. Chlamydial metabolism revisited: interspecies metabolic variability and developmental stage-specific physiologic activities. FEMS Microbiol Rev 2014; 38:779-801. [PMID: 24484402 DOI: 10.1111/1574-6976.12059] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 01/07/2023] Open
Abstract
Chlamydiae are a group of obligate intracellular bacteria comprising important human and animal pathogens as well as symbionts of ubiquitous protists. They are characterized by a developmental cycle including two main morphologically and physiologically distinct stages, the replicating reticulate body and the infectious nondividing elementary body. In this review, we reconstruct the history of studies that have led to our current perception of chlamydial physiology, focusing on their energy and central carbon metabolism. We then compare the metabolic capabilities of pathogenic and environmental chlamydiae highlighting interspecies variability among the metabolically more flexible environmental strains. We discuss recent findings suggesting that chlamydiae may not live as energy parasites throughout the developmental cycle and that elementary bodies are not metabolically inert but exhibit metabolic activity under appropriate axenic conditions. The observed host-free metabolic activity of elementary bodies may reflect adequate recapitulation of the intracellular environment, but there is evidence that this activity is biologically relevant and required for extracellular survival and maintenance of infectivity. The recent discoveries call for a reconsideration of chlamydial metabolism and future in-depth analyses to better understand how species- and stage-specific differences in chlamydial physiology may affect virulence, tissue tropism, and host adaptation.
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Affiliation(s)
- Anders Omsland
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Hamilton, MT, USA
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12
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Pilhofer M, Aistleitner K, Ladinsky MS, König L, Horn M, Jensen GJ. Architecture and host interface of environmental chlamydiae revealed by electron cryotomography. Environ Microbiol 2013; 16:417-29. [PMID: 24118768 PMCID: PMC4949044 DOI: 10.1111/1462-2920.12299] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 09/26/2013] [Indexed: 01/14/2023]
Abstract
Chlamydiae comprise important pathogenic and symbiotic bacteria that alternate between morphologically and physiologically different life stages during their developmental cycle. Using electron cryotomography, we characterize the ultrastructure of the developmental stages of three environmental chlamydiae: Parachlamydia acanthamoebae, Protochlamydia amoebophila and Simkania negevensis. We show that chemical fixation and dehydration alter the cell shape of Parachlamydia and that the crescent body is not a developmental stage, but an artefact of conventional electron microscopy. We further reveal type III secretion systems of environmental chlamydiae at macromolecular resolution and find support for a chlamydial needle-tip protein. Imaging bacteria inside their host cells by cryotomography for the first time, we observe marked differences in inclusion morphology and development as well as host organelle recruitment between the three chlamydial organisms, with Simkania inclusions being tightly enveloped by the host endoplasmic reticulum. The study demonstrates the power of electron cryotomography to reveal structural details of bacteria-host interactions that are not accessible using traditional methods.
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Affiliation(s)
- Martin Pilhofer
- Division of Biology, California Institute of Technology, Pasadena, CA, 91125, USA; Howard Hughes Medical Institute, Pasadena, CA, 91125, USA
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Sixt BS, Kostanjšek R, Mustedanagic A, Toenshoff ER, Horn M. Developmental cycle and host interaction of Rhabdochlamydia porcellionis, an intracellular parasite of terrestrial isopods. Environ Microbiol 2013; 15:2980-93. [PMID: 24024954 DOI: 10.1111/1462-2920.12252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 08/05/2013] [Accepted: 08/12/2013] [Indexed: 12/01/2022]
Abstract
Environmental chlamydiae are a diverse group of obligate intracellular bacteria related to well-known pathogens of humans. To date, only very little is known about chlamydial species infecting arthropods. In this study, we used cocultivation with insect cells for recovery and maintenance of Rhabdochlamydia porcellionis, a parasite of the crustacean host Porcellio scaber. In vitro, the infection cycle of R. porcellionis was completed within 7 days, resulting in the release of infectious particles by host cell lysis. Lack of apoptosis induction during the entire course of infection, combined with a reduced sensitivity of infected cultures to experimentally induced programmed cell death, indicates that R. porcellionis like its human pathogenic relatives counteracts this host defence mechanism. Interestingly, the rod-shaped variant of R. porcellionis, proposed to represent their mature infective stage, was not detected in cell culture, suggesting that its development may require prolonged maturation or may be triggered by specific conditions encountered only in the animal host. This first cell culture-based system for the cultivation and investigation of an arthropod-associated chlamydial species will help to better understand the biology of a so far neglected group of chlamydiae and its recently suggested potential to cause disease in humans.
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Affiliation(s)
- Barbara S Sixt
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Azra Mustedanagic
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Elena R Toenshoff
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
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Sixt BS, Hiess B, König L, Horn M. Lack of effective anti-apoptotic activities restricts growth of Parachlamydiaceae in insect cells. PLoS One 2012; 7:e29565. [PMID: 22253735 PMCID: PMC3253803 DOI: 10.1371/journal.pone.0029565] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 11/30/2011] [Indexed: 12/02/2022] Open
Abstract
The fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae. As inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might represent emerging pathogens. While Simkania negevensis was able to efficiently replicate within insect cells, which served as model for metazoan-derived host cells, the Parachlamydiaceae (Parachlamydia acanthamoebae and Protochlamydia amoebophila) displayed limited intracellular growth, yet these bacteria induced typical features of apoptotic cell death, including formation of apoptotic bodies, nuclear condensation, internucleosomal DNA fragmentation, and effector caspase activity. Induction of apoptosis was dependent on bacterial activity, but not bacterial de novo protein synthesis, and was detectable already at very early stages of infection. Experimental inhibition of host cell death greatly enhanced parachlamydial replication, suggesting that lack of potent anti-apoptotic activities in Parachlamydiaceae may represent an important factor compromising their ability to successfully infect non-protozoan hosts. These findings highlight the importance of the evolution of anti-apoptotic traits for the success of chlamydiae as pathogens of humans and animals.
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Affiliation(s)
- Barbara S. Sixt
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Birgit Hiess
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Lena König
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Matthias Horn
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
- * E-mail:
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15
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Abstract
Intracellular bacteria live in an environment rich in most essential metabolites but need special mechanisms to access these substrates. Nucleotide transport proteins (NTTs) catalyze the import of ATP and other nucleotides from the eukaryotic host into the bacterial cell and render de novo synthesis of these compounds dispensable. The draft genome sequence of Simkania negevensis strain Z, a chlamydial organism considered a newly emerging pathogen, revealed four genes encoding putative nucleotide transport proteins (SnNTT1 to SnNTT4), all of which are transcribed during growth of S. negevensis in Acanthamoeba host cells, as confirmed by reverse transcription-PCR. Using heterologous expression in Escherichia coli, we could show that SnNTT1 functions as an ATP/ADP antiporter, SnNTT2 as a guanine nucleotide/ATP/H(+) symporter driven by the membrane potential, and SnNTT3 as a nucleotide triphosphate antiporter. In addition, SnNTT3 is able to transport dCTP, which has not been shown for a prokaryotic transport protein before. No substrate could be identified for SnNTT4. Taking these data together, S. negevensis employs a set of nucleotide transport proteins to efficiently tap its host's energy and nucleotide pools. Although similar to other chlamydiae, these transporters show distinct and unique adaptations with respect to substrate specificities and mode of transport.
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Abstract
Despite using modern microbiological diagnostic approaches, the aetiological agents of pneumonia remain unidentified in about 50% of cases. Some bacteria that grow poorly or not at all in axenic media used in routine clinical bacteriology laboratory but which can develop inside amoebae may be the agents of these lower respiratory tract infections (RTIs) of unexplained aetiology. Such amoebae-resisting bacteria, which coevolved with amoebae to resist their microbicidal machinery, may have developed virulence traits that help them survive within human macrophages, i.e. the first line of innate immune defence in the lung. We review here the current evidence for the emerging pathogenic role of various amoebae-resisting microorganisms as agents of RTIs in humans. Specifically, we discuss the emerging pathogenic roles of Legionella-like amoebal pathogens, novel Chlamydiae (Parachlamydia acanthamoebae, Simkania negevensis), waterborne mycobacteria and Bradyrhizobiaceae (Bosea and Afipia spp.).
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Affiliation(s)
- Frédéric Lamoth
- Infectious Diseases Service, University of Lausanne, Lausanne, Switzerland
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Abstract
Members of the phylum Chlamydiae are obligate intracellular bacteria that were discovered about a century ago. Although Chlamydiae are major pathogens of humans and animals, they were long recognized only as a phylogenetically well-separated, small group of closely related microorganisms. The diversity of chlamydiae, their host range, and their occurrence in the environment had been largely underestimated. Today, several chlamydia-like bacteria have been described as symbionts of free-living amoebae and other eukaryotic hosts. Some of these environmental chlamydiae might also be of medical relevance for humans. Their analysis has contributed to a broader understanding of chlamydial biology and to novel insights into the evolution of these unique microorganisms.
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Affiliation(s)
- Matthias Horn
- Department of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria.
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Kahane S, Dvoskin B, Friedman MG. The role of monocyte/macrophages as vehicles of dissemination ofSimkania negevensis: anin vitrosimulation model. ACTA ACUST UNITED AC 2008; 52:219-27. [DOI: 10.1111/j.1574-695x.2007.00361.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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