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Greub G, Pillonel T, Bavoil PM, Borel N, Campbell LA, Dean D, Hefty S, Horn M, Morré SA, Ouellette SP, Pannekoek Y, Puolakkainen M, Timms P, Valdivia R, Vanrompay D. Use of gene sequences as type for naming prokaryotes: Recommendations of the international committee on the taxonomy of chlamydiae. New Microbes New Infect 2023; 54:101158. [PMID: 37416863 PMCID: PMC10320375 DOI: 10.1016/j.nmni.2023.101158] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 06/01/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
The International Committee on Systematics of Prokaryotes (ICSP) discussed and rejected in 2020 a proposal to modify the International Code of Nomenclature of Prokaryotes to allow the use of gene sequences as type for naming prokaryotes. An alternative nomenclatural code, the Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode), which considers genome sequences as type material for naming species, was published in 2022. Members of the ICSP subcommittee for the taxonomy of the phylum Chlamydiae (Chlamydiota) consider that the use of gene sequences as type would benefit the taxonomy of microorganisms that are difficult to culture such as the chlamydiae and other strictly intracellular bacteria. We recommend the registration of new names of uncultured prokaryotes in the SeqCode registry.
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Affiliation(s)
- Gilbert Greub
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011, Lausanne, Switzerland
| | - Trestan Pillonel
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011, Lausanne, Switzerland
| | - Patrik M. Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Nicole Borel
- Department of Pathobiology, Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, CH-8057, Zurich, Switzerland
| | - Lee Ann Campbell
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Deborah Dean
- Departments of Medicine and Pediatrics, University of California San Francisco School of Medicine, Oakland, CA, USA
| | - Scott Hefty
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090, Vienna, Austria
| | - Servaas A. Morré
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
- Institute for Public Health Genomics (IPHG), Department of Genetics and Cell Biology, Research School GROW (School for Oncology & Developmental Biology), Faculty of Health, Medicine & Life Sciences, University of Maastricht, Maastricht, the Netherlands
- Dutch Chlamydia Trachomatis Reference Laboratory, Department of Medical Microbiology & Infection Control, VU University Medical Centre, Amsterdam, the Netherlands
| | - Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yvonne Pannekoek
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Mirja Puolakkainen
- Department of Virology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Peter Timms
- Genecology Research Center, University of Sunshine Coast, Queensland, Australia
| | - Raphael Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, 27710, USA
| | - Daisy Vanrompay
- Department of Animal Science and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
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2
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Edwards VL, McComb E, Gleghorn JP, Forney L, Bavoil PM, Ravel J. Three-dimensional models of the cervicovaginal epithelia to study host-microbiome interactions and sexually transmitted infections. Pathog Dis 2022; 80:6655985. [PMID: 35927516 PMCID: PMC9419571 DOI: 10.1093/femspd/ftac026] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/14/2022] [Accepted: 08/02/2022] [Indexed: 02/03/2023] Open
Abstract
2D cell culture systems have historically provided controlled, reproducible means to analyze host-pathogen interactions observed in the human reproductive tract. Although inexpensive, straightforward, and requiring a very short time commitment, these models recapitulate neither the functionality of multilayered cell types nor the associated microbiome that occurs in a human. Animal models have commonly been used to recreate the complexity of human infections. However, extensive modifications of animal models are required to recreate interactions that resemble those in the human reproductive tract. 3D cell culture models have emerged as alternative means of reproducing vital elements of human infections at a fraction of the cost of animal models and on a scale that allows for replicative experiments. Here, we describe a new 3D model that utilizes transwells with epithelial cells seeded apically and a basolateral extracellular matrix (ECM)-like layer. The model produced tissues with morphologic and physiological resemblance to human cervical and vaginal epithelia, including mucus levels produced by cervical cells. Infection by Chlamydia trachomatis and Neisseria gonorrhoeae was demonstrated, as well as the growth of bacterial species observed in the human vaginal microbiota. This enabled controlled mechanistic analyses of the interactions between host cells, the vaginal microbiota, and STI pathogens. Affordable and semi high-throughput 3D models of the cervicovaginal epithelia that are physiologically relevant by sustaining vaginal bacterial colonization, and facilitate studies of chlamydial and gonococcal infections.
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Affiliation(s)
- Vonetta L Edwards
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | | | - Jason P Gleghorn
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Larry Forney
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Patrik M Bavoil
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States,Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States
| | - Jacques Ravel
- Corresponding author: Institute for Genome Sciences and Department of Microbiology and Immunology, University of Maryland School of Medicine, Health Science Research Facility (HSRDF), 670 W. Baltimore Street, Baltimore, MD 21201, United States. Tel: +1 410-706-5674; E-mail:
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3
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Marques PX, Wand H, Nandy M, Tan C, Shou H, Terplan M, Mark K, Brotman RM, Wilson DP, Ravel J, Hsia RC, Bavoil PM. Serum antibodies to surface proteins of Chlamydia trachomatis as candidate biomarkers of disease: results from the Baltimore Chlamydia Adolescent/Young Adult Reproductive Management (CHARM) cohort. FEMS Microbes 2022. [DOI: 10.1093/femsmc/xtac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
ABSTRACT
We previously observed that the nine-member family of autotransported polymorphic membrane proteins (Pmps) of Chlamydia trachomatis is variably expressed in cell culture. Additionally, C. trachomatis-infected patients display variable Pmp-specific serum antibody profiles indirectly suggesting expression of unique Pmp profiles is an adaptive response to host-specific stimuli during infection. Here, we propose that the host response to Pmps and other outer surface proteins may correlate with disease severity.
This study tests this hypothesis using an ELISA that measures serum IgG antibodies specific for the nine C. trachomatis Pmp subtypes and four immunodominant antigens (MOMP, OmcB, Hsp60, ClpP) in 265 participants of the Chlamydia Adolescent/Young Adult Reproductive Management (CHARM) cohort.
More C. trachomatis-infected females displayed high Pmp-specific antibody levels (cut-off Indexes) than males (35.9–40.7% of females vs. 24.2–30.0% of males), with statistical significance for PmpC, F and H (P<0.05). Differences in Pmp-specific antibody profiles were not observed between C. trachomatis-infected females with a clinical diagnosis of pelvic inflammatory disease (PID) and those without. However, a statistically significant association between high levels of OmcB-specific antibody and a PID diagnosis (P<0.05) was observed.
Using antibody levels as an indirect measure of antigen expression, our results suggest that gender- and/or site-specific (cervix in females vs. urethra in males) stimuli may control pmp expression in infected patients. They also support the possible existence of immune biomarkers of chlamydial infection associated with disease and underline the need for high resolution screening in human serum.
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Affiliation(s)
- Patricia X Marques
- Dept of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Handan Wand
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Melissa Nandy
- Dept of Institute for Genome Science, University of Maryland, Baltimore, MD, USA
| | - Chun Tan
- Dept of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Huizhong Shou
- Dept of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Mishka Terplan
- Dept of Obstetrics & Gynecology, University of Maryland, Baltimore, MD, USA
| | - Katrina Mark
- Dept of Pediatrics, University of Maryland, Baltimore, MD, USA
| | - Rebecca M Brotman
- Dept of Institute for Genome Science, University of Maryland, Baltimore, MD, USA
| | | | - Jacques Ravel
- Dept of Microbiology and Immunology, University of Maryland, Baltimore, MD, USA
- Dept of Institute for Genome Science, University of Maryland, Baltimore, MD, USA
| | - Ru-ching Hsia
- Dept of Electron Microscopy Core Imaging Facility, University of Maryland, Baltimore, MD, USA
| | - Patrik M Bavoil
- Dept of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
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4
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Vorimore F, Hölzer M, Liebler-Tenorio EM, Barf LM, Delannoy S, Vittecoq M, Wedlarski R, Lécu A, Scharf S, Blanchard Y, Fach P, Hsia RC, Bavoil PM, Rosselló-Móra R, Laroucau K, Sachse K. Evidence for the existence of a new genus Chlamydiifrater gen. nov. inside the family Chlamydiaceae with two new species isolated from flamingo (Phoenicopterus roseus): Chlamydiifrater phoenicopteri sp. nov. and Chlamydiifrater volucris sp. nov. Syst Appl Microbiol 2021; 44:126200. [PMID: 34298369 DOI: 10.1016/j.syapm.2021.126200] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [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: 11/19/2020] [Revised: 03/01/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022]
Abstract
The family Chlamydiaceae currently comprises a single genus Chlamydia, with 11 validly published species and seven more taxa. It includes the human pathogens Chlamydia (C.) trachomatis, C. pneumoniae and C. psittaci, a zoonotic agent causing avian chlamydiosis and human psittacosis, as well as other proven or potential pathogens in ruminants, birds, snakes, reptiles and turtles. During routine testing of 15 apparently healthy captive flamingos in a zoo in 2011, an atypical strain of Chlamydiaceae was detected by real-time PCR of cloacal swab samples. Sequence analysis of the 16S rRNA gene revealed high similarity to the uncultured Chlamydiales bacterium clone 122, which previously had been found in gulls. As more samples were collected during annual campaigns of the flamingo ringing program in southern France from 2012 to 2015, Chlamydiaceae-specific DNA was detected by PCR in 30.9% of wild birds. From these samples, three strains were successfully grown in cell culture. Ultrastructural analysis, comparison of 16S and 23S rRNA gene sequences, whole-genome analysis based on de novo hybrid-assembled sequences of the new strains as well as subsequent calculation of taxonomic parameters revealed that the relatedness of the flamingo isolates to established members of the family Chlamydiaceae was sufficiently distant to indicate that the three strains belong to two distinct species within a new genus. Based on these data, we propose the introduction of Chlamydiifrater gen. nov., as a new genus, and Chlamydiifrater phoenicopteri sp. nov. and Chlamydiifrater volucris sp. nov., as two new species of the genus.
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Affiliation(s)
- F Vorimore
- University Paris-Est, Anses, Animal Health Laboratory, Bacterial Zoonoses Unit, Maisons-Alfort, France.
| | - M Hölzer
- Robert Koch Institute, MF1 Bioinformatics, Berlin, Germany
| | - E M Liebler-Tenorio
- Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Institute of Molecular Pathogenesis, Germany
| | - L-M Barf
- Friedrich-Schiller-Universität Jena, RNA Bioinformatics and High-Throughput Analysis, Jena, Germany
| | - S Delannoy
- University Paris-Est, Anses, Food Research Laboratory, IdentyPath Platform, Maisons-Alfort, France
| | - M Vittecoq
- Tour du Valat, Centre de recherche pour la conservation des zones humides méditerranéennes, Le Sambuc, Arles, France
| | - R Wedlarski
- Bioparc - Zoo de Doué la fontaine, 103 rue de Cholet, 49700 Doué la Fontaine, France
| | - A Lécu
- Parc Zoologique de Paris, avenue de Daumesnil, 75012 Paris, France
| | - S Scharf
- Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Institute of Molecular Pathogenesis, Germany
| | - Y Blanchard
- Unit of Viral Genetics and Biosafety, ANSES, Laboratory of Ploufragan, Ploufragan, France
| | - P Fach
- University Paris-Est, Anses, Food Research Laboratory, IdentyPath Platform, Maisons-Alfort, France
| | - R C Hsia
- University of Maryland, Electron Microscopy Core Imaging Facility, Baltimore, MD 21201, USA
| | - P M Bavoil
- University of Maryland, Department of Microbial Pathogenesis, Baltimore, MD 21201, USA
| | - R Rosselló-Móra
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity, Mediterranean Institute for Advanced Studies, 07190 Esporles, Spain
| | - K Laroucau
- University Paris-Est, Anses, Animal Health Laboratory, Bacterial Zoonoses Unit, Maisons-Alfort, France
| | - K Sachse
- Friedrich-Schiller-Universität Jena, RNA Bioinformatics and High-Throughput Analysis, Jena, Germany
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5
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Tamarelle J, Ma B, Gajer P, Humphrys MS, Terplan M, Mark KS, Thiébaut ACM, Forney LJ, Brotman RM, Delarocque-Astagneau E, Bavoil PM, Ravel J. Nonoptimal Vaginal Microbiota After Azithromycin Treatment for Chlamydia trachomatis Infection. J Infect Dis 2020; 221:627-635. [PMID: 31573603 PMCID: PMC7530545 DOI: 10.1093/infdis/jiz499] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/27/2019] [Indexed: 12/26/2022] Open
Abstract
We characterized the composition and structure of the vaginal microbiota in a cohort of 149 women with genital Chlamydia trachomatis infection at baseline who were followed quarterly for 9 months after antibiotic treatment. At time of diagnosis, the vaginal microbiota was dominated by Lactobacillus iners or a diverse array of bacterial vaginosis–associated bacteria including Gardnerella vaginalis. Interestingly, L. iners–dominated communities were most common after azithromycin treatment (1 g monodose), consistent with the observed relative resistance of L. iners to azithromycin. Lactobacillus iners–dominated communities have been associated with increased risk of C. trachomatis infection, suggesting that the impact of antibiotic treatment on the vaginal microbiota could favor reinfections. These results provide support for the dual need to account for the potential perturbing effect(s) of antibiotic treatment on the vaginal microbiota, and to develop strategies to protect and restore optimal vaginal microbiota.
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Affiliation(s)
- Jeanne Tamarelle
- Unité Mixte de Recherche 1181 , Université Versailles-Saint-Quentin-en-Yvelines, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Bing Ma
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pawel Gajer
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mike S Humphrys
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mishka Terplan
- Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA, Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Katrina S Mark
- Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA, Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Anne C M Thiébaut
- Unité Mixte de Recherche 1181 , Université Versailles-Saint-Quentin-en-Yvelines, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Larry J Forney
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | - Rebecca M Brotman
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Elisabeth Delarocque-Astagneau
- Unité Mixte de Recherche 1181 , Université Versailles-Saint-Quentin-en-Yvelines, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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6
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Borgogna JLC, Shardell MD, Yeoman CJ, Ghanem KG, Kadriu H, Ulanov AV, Gaydos CA, Hardick J, Robinson CK, Bavoil PM, Ravel J, Brotman RM, Tuddenham S. The association of Chlamydia trachomatis and Mycoplasma genitalium infection with the vaginal metabolome. Sci Rep 2020; 10:3420. [PMID: 32098988 PMCID: PMC7042340 DOI: 10.1038/s41598-020-60179-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 08/30/2019] [Accepted: 02/03/2020] [Indexed: 11/25/2022] Open
Abstract
Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) are two highly prevalent bacterial sexually transmitted infections (STIs) with a significant rate of co-infection in some populations. Vaginal metabolites are influenced by resident vaginal microbiota, affect susceptibility to sexually transmitted infections (STIs), and may impact local inflammation and patient symptoms. Examining the vaginal metabolome in the context of CT mono (CT+) and CT/MG co-infection (CT+/MG+) may identify biomarkers for infection or provide new insights into disease etiology and pathogenesis. Yet, the vaginal metabolome in the setting of CT infection is understudied and the composition of the vaginal metabolome in CT/MG co-infected women is unknown. Therefore, in this analysis, we used an untargeted metabolomic approach combined with 16S rRNA gene amplicon sequencing to characterize the vaginal microbiota and metabolomes of CT+, CT+/MG+, and uninfected women. We found that CT+ and CT+/MG+ women had distinct vaginal metabolomic profiles as compared to uninfected women both before and after adjustment for the vaginal microbiota. This study provides important foundational data documenting differences in the vaginal metabolome between CT+, CT+/MG+ and uninfected women. These data may guide future mechanistic studies that seek to provide insight into the pathogenesis of CT and CT/MG infections.
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Affiliation(s)
| | - Michelle D Shardell
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Carl J Yeoman
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
- Department of Animal and Range Sciences, Montana State University, Bozeman, MT, USA
| | - Khalil G Ghanem
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Herlin Kadriu
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Alexander V Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois, Urbana-Champaign, IL, USA
| | - Charlotte A Gaydos
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Justin Hardick
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Courtney K Robinson
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rebecca M Brotman
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Susan Tuddenham
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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7
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Edwards VL, Smith SB, McComb EJ, Tamarelle J, Ma B, Humphrys MS, Gajer P, Gwilliam K, Schaefer AM, Lai SK, Terplan M, Mark KS, Brotman RM, Forney LJ, Bavoil PM, Ravel J. The Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection. mBio 2019; 10:e01548-19. [PMID: 31409678 PMCID: PMC6692509 DOI: 10.1128/mbio.01548-19] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [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: 06/14/2019] [Accepted: 07/09/2019] [Indexed: 12/02/2022] Open
Abstract
The mechanism(s) by which Lactobacillus-dominated cervicovaginal microbiota provide a barrier to Chlamydia trachomatis infection remain(s) unknown. Here we evaluate the impact of different Lactobacillus spp. identified via culture-independent metataxonomic analysis of C. trachomatis-infected women on C. trachomatis infection in a three-dimensional (3D) cervical epithelium model. Lactobacillus spp. that specifically produce d(-) lactic acid were associated with long-term protection against C. trachomatis infection, consistent with reduced protection associated with Lactobacillus iners, which does not produce this isoform, and with decreased epithelial cell proliferation, consistent with the observed prolonged protective effect. Transcriptomic analysis revealed that epigenetic modifications involving histone deacetylase-controlled pathways are integral to the cross talk between host and microbiota. These results highlight a fundamental mechanism whereby the cervicovaginal microbiota modulates host functions to protect against C. trachomatis infection.IMPORTANCE The vaginal microbiota is believed to protect women against Chlamydia trachomatis, the etiologic agent of the most prevalent sexually transmitted infection (STI) in developed countries. The mechanism underlying this protection has remained elusive. Here, we reveal the comprehensive strategy by which the cervicovaginal microbiota modulates host functions to protect against chlamydial infection, thereby providing a novel conceptual mechanistic understanding. Major implications of this work are that (i) the impact of the vaginal microbiota on the epithelium should be considered in future studies of chlamydial infection and other STIs and (ii) a fundamental understanding of the cervicovaginal microbiota's role in protection against STIs may enable the development of novel microbiome-based therapeutic strategies to protect women from infection and improve vaginal and cervical health.
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Affiliation(s)
- Vonetta L Edwards
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Steven B Smith
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Elias J McComb
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jeanne Tamarelle
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, Institut Pasteur, INSERM, Université de Versailles-Saint-Quentin-en-Yvelines, Versailles, France
| | - Bing Ma
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Michael S Humphrys
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pawel Gajer
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kathleen Gwilliam
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Alison M Schaefer
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Samuel K Lai
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Mishka Terplan
- Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Katrina S Mark
- Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rebecca M Brotman
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Larry J Forney
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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8
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Bavoil PM, Marques PX, Brotman R, Ravel J. Does Active Oral Sex Contribute to Female Infertility? J Infect Dis 2017; 216:932-935. [PMID: 29029270 DOI: 10.1093/infdis/jix419] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 08/16/2017] [Indexed: 12/14/2022] Open
Abstract
Based on recent, historical, and circumstantial evidence, we present a multifactorial hypothesis that has potential direct implications on the epidemiology and management of chlamydial infection and disease in humans. We propose that (1) like its veterinary relatives, the oculogenital pathogen Chlamydia trachomatis evolved as a commensal organism of the human gastrointestinal (GI) tract primarily transmissible via the fecal-oral route; (2) in the modern era, C. trachomatis causes "opportunistic" infection at non-GI sites under conditions driven by improved sanitation/hygiene and reduced fecal-oral transmission; and (3) the rise in the practice of oral sex is contributing to the increased prevalence of C. trachomatis in the human GI tract. Infectious organisms produced in the GI tract and reaching the rectum may then chronically contaminate and infect the female urogenital tract, thereby potentially contributing to the most serious sequelae of chlamydial infection in women: pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility.
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Affiliation(s)
- Patrik M Bavoil
- Department of Microbial Pathogenesis, School of Dentistry.,Department of Microbiology and Immunology
| | | | - Rebecca Brotman
- Institute for Genome Science.,Department of Epidemiology and Public Health, School of Medicine, University of Maryland, Baltimore
| | - Jacques Ravel
- Department of Microbiology and Immunology.,Institute for Genome Science
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9
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10
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Bavoil PM, Byrne GI. Analysis of CPAF mutants: new functions, new questions (the ins and outs of a chlamydial protease). Pathog Dis 2015; 71:287-91. [PMID: 24942261 DOI: 10.1111/2049-632x.12194] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 06/06/2014] [Indexed: 12/18/2022] Open
Abstract
The role of the chlamydial protease CPAF, previously described as a secreted serine protease processing a wealth of host and chlamydial proteins to promote chlamydial intracellular growth, has recently been questioned by studies from the groups of Tan and Sütterlin, who demonstrated that the reported proteolysis of almost a dozen substrates by CPAF occurred during preparation of cell lysates rather than in intact cells. Valdivia et al. have now compared near-isogenic pairs of CPAF-deficient and secretion-deficient mutants of Chlamydia trachomatis and their wild-type parent. Their report, published in this issue of Pathogens and Disease, is a landmark study in the emerging era of Chlamydia genetics. The results of Tan and Sütterlin are confirmed with a few additions. While CPAF's role in pathogenesis is diminished considerably from these studies, CPAF remains an important factor in chlamydial biology as (1) CPAF mutants produce less infectious yield than wild type; and (2) CPAF is responsible for proteolytic cleavage of vimentin and LAP-1, but only after lysis of the inclusion membrane, not upon CPAF secretion to the cytosol. Here, we briefly review the evidence in support of CPAF's active secretion from the mid-to-late inclusion and conclude that new experimentation to establish whether or not CPAF is actively secreted should precede any new investigation of CPAF's cellular activities during mid-to-late development.
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Affiliation(s)
- Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD, USA
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11
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Mojica SA, Hovis KM, Frieman MB, Tran B, Hsia RC, Ravel J, Jenkins-Houk C, Wilson KL, Bavoil PM. SINC, a type III secreted protein of Chlamydia psittaci, targets the inner nuclear membrane of infected cells and uninfected neighbors. Mol Biol Cell 2015; 26:1918-34. [PMID: 25788290 PMCID: PMC4436835 DOI: 10.1091/mbc.e14-11-1530] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/06/2015] [Indexed: 12/31/2022] Open
Abstract
SINC, a new type III secreted protein of the avian and human pathogen Chlamydia psittaci, uniquely targets the nuclear envelope of C. psittaci-infected cells and uninfected neighboring cells. Digitonin-permeabilization studies of SINC-GFP-transfected HeLa cells indicate that SINC targets the inner nuclear membrane. SINC localization at the nuclear envelope was blocked by importazole, confirming SINC import into the nucleus. Candidate partners were identified by proximity to biotin ligase-fused SINC in HEK293 cells and mass spectrometry (BioID). This strategy identified 22 candidates with high confidence, including the nucleoporin ELYS, lamin B1, and four proteins (emerin, MAN1, LAP1, and LBR) of the inner nuclear membrane, suggesting that SINC interacts with host proteins that control nuclear structure, signaling, chromatin organization, and gene silencing. GFP-SINC association with the native LEM-domain protein emerin, a conserved component of nuclear "lamina" structure, or with a complex containing emerin was confirmed by GFP pull down. Our findings identify SINC as a novel bacterial protein that targets the nuclear envelope with the capability of globally altering nuclear envelope functions in the infected host cell and neighboring uninfected cells. These properties may contribute to the aggressive virulence of C. psittaci.
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Affiliation(s)
- Sergio A Mojica
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201
| | - Kelley M Hovis
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201
| | - Matthew B Frieman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 20201
| | - Bao Tran
- Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, MD 21201
| | - Ru-ching Hsia
- Core Imaging Facility and Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201
| | - Jacques Ravel
- Institute for Genome Science, University of Maryland School of Medicine, Baltimore, MD 20201
| | - Clifton Jenkins-Houk
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201
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12
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Neuendorf E, Gajer P, Bowlin AK, Marques PX, Ma B, Yang H, Fu L, Humphrys MS, Forney LJ, Myers GSA, Bavoil PM, Rank RG, Ravel J. Chlamydia caviae infection alters abundance but not composition of the guinea pig vaginal microbiota. Pathog Dis 2015; 73:ftv019. [PMID: 25761873 PMCID: PMC4445005 DOI: 10.1093/femspd/ftv019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2015] [Indexed: 01/09/2023] Open
Abstract
In humans, the vaginal microbiota is thought to be the first line of defense again pathogens including Chlamydia trachomatis. The guinea pig has been extensively used as a model to study chlamydial infection because it shares anatomical and physiological similarities with humans, such as a squamous vaginal epithelium as well as some of the long-term outcomes caused by chlamydial infection. In this study, we aimed to evaluate the guinea pig-C. caviae model of genital infection as a surrogate for studying the role of the vaginal microbiota in the early steps of C. trachomatis infection in humans. We used culture-independent molecular methods to characterize the relative and absolute abundance of bacterial phylotypes in the guinea pig vaginal microbiota in animals non-infected, mock-infected or infected by C. caviae. We showed that the guinea pig and human vaginal microbiotas are of different bacterial composition and abundance. Chlamydia caviae infection had a profound effect on the absolute abundance of bacterial phylotypes but not on the composition of the guinea pig vaginal microbiota. Our findings compromise the validity of the guinea pig-C. caviae model to study the role of the vaginal microbiota during the early steps of sexually transmitted infection. The vaginal microbiota of the guinea pig differs from that of humans and cannot prevent chlamydial infections efficiently.
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Affiliation(s)
- Elizabeth Neuendorf
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Pawel Gajer
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Anne K Bowlin
- Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Patricia X Marques
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Bing Ma
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hongqiu Yang
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Li Fu
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael S Humphrys
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Larry J Forney
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID 83843, USA
| | - Garry S A Myers
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Patrik M Bavoil
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID 83843, USA
| | - Roger G Rank
- Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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13
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Sachse K, Bavoil PM, Kaltenboeck B, Stephens RS, Kuo CC, Rosselló-Móra R, Horn M. Emendation of the family Chlamydiaceae: proposal of a single genus, Chlamydia, to include all currently recognized species. Syst Appl Microbiol 2015; 38:99-103. [PMID: 25618261 DOI: 10.1016/j.syapm.2014.12.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 12/22/2014] [Accepted: 12/27/2014] [Indexed: 01/29/2023]
Abstract
The family Chlamydiaceae (order Chlamydiales, phylum Chlamydiae) comprises important, obligate intracellular bacterial pathogens of humans and animals. Subdivision of the family into the two genera Chlamydia and Chlamydophila has been discussed controversially during the past decade. Here, we have revisited the current classification in the light of recent genomic data and in the context of the unique biological properties of these microorganisms. We conclude that neither generally used 16S rRNA sequence identity cut-off values nor parameters based on genomic similarity consistently separate the two genera. Notably, no easily recognizable phenotype such as host preference or tissue tropism is available that would support a subdivision. In addition, the genus Chlamydophila is currently not well accepted and not used by a majority of research groups in the field. Therefore, we propose the classification of all 11 currently recognized Chlamydiaceae species in a single genus, the genus Chlamydia. Finally, we provide emended descriptions of the family Chlamydiaceae, the genus Chlamydia, as well as the species Chlamydia abortus, Chlamydia caviae and Chlamydia felis.
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Affiliation(s)
- Konrad Sachse
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Jena, Germany.
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Bernhard Kaltenboeck
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA
| | - Richard S Stephens
- Program in Infectious Diseases, University of California, Berkeley, CA, USA
| | | | - Ramon Rosselló-Móra
- Mediterranean Institute for Advanced studies (IMEDEA, CSIC-UIB), Esporles, Illes Balears, Spain
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
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14
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Prosser JI, Cole JA, Nielsen J, Bavoil PM, Häggblom MM. Most influential FEMS publications. FEMS Microbiol Lett 2014; 354:83-4. [PMID: 24842770 DOI: 10.1111/1574-6968.12444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A selection of influential FEMS publications to celebrate the 40th anniversary of FEMS.
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Affiliation(s)
- James I Prosser
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK.
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15
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Abstract
The word persistence was used by Chlamydia researchers almost as soon as Chlamydia research was born to reflect the propensity of chlamydiae to cause inapparent infection in their hosts, from birds to humans. More recently, the term persistence has been used, misused, and sometimes abused amidst in vitro and in vivo studies that aim to mimick the ability of chlamydiae to emerge from the presumed inapparent state into clinically detectable infection and disease. Here, I have attempted to provide a global perspective on the state of research on chlamydial persistence, revisiting old observations that may warrant a new look, critically evaluating more recent observations and their shortcomings, and including recent developments that may help redefine chlamydiae as pathogens-or not-of both animals and humans.
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Affiliation(s)
- Patrik M. Bavoil
- Department of Microbial Pathogenesis, School of Dentistry, University of MarylandBaltimore, MD, USA
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16
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Humphrys MS, Creasy T, Sun Y, Shetty AC, Chibucos MC, Drabek EF, Fraser CM, Farooq U, Sengamalay N, Ott S, Shou H, Bavoil PM, Mahurkar A, Myers GSA. Simultaneous transcriptional profiling of bacteria and their host cells. PLoS One 2013; 8:e80597. [PMID: 24324615 PMCID: PMC3851178 DOI: 10.1371/journal.pone.0080597] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [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: 09/18/2013] [Accepted: 10/14/2013] [Indexed: 02/06/2023] Open
Abstract
We developed an RNA-Seq-based method to simultaneously capture prokaryotic and eukaryotic expression profiles of cells infected with intracellular bacteria. As proof of principle, this method was applied to Chlamydia trachomatis-infected epithelial cell monolayers in vitro, successfully obtaining transcriptomes of both C. trachomatis and the host cells at 1 and 24 hours post-infection. Chlamydiae are obligate intracellular bacterial pathogens that cause a range of mammalian diseases. In humans chlamydiae are responsible for the most common sexually transmitted bacterial infections and trachoma (infectious blindness). Disease arises by adverse host inflammatory reactions that induce tissue damage & scarring. However, little is known about the mechanisms underlying these outcomes. Chlamydia are genetically intractable as replication outside of the host cell is not yet possible and there are no practical tools for routine genetic manipulation, making genome-scale approaches critical. The early timeframe of infection is poorly understood and the host transcriptional response to chlamydial infection is not well defined. Our simultaneous RNA-Seq method was applied to a simplified in vitro model of chlamydial infection. We discovered a possible chlamydial strategy for early iron acquisition, putative immune dampening effects of chlamydial infection on the host cell, and present a hypothesis for Chlamydia-induced fibrotic scarring through runaway positive feedback loops. In general, simultaneous RNA-Seq helps to reveal the complex interplay between invading bacterial pathogens and their host mammalian cells and is immediately applicable to any bacteria/host cell interaction.
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Affiliation(s)
- Michael S. Humphrys
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Todd Creasy
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Yezhou Sun
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Amol C. Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Marcus C. Chibucos
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Elliott F. Drabek
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Claire M. Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Umar Farooq
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Naomi Sengamalay
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Sandy Ott
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Huizhong Shou
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Patrik M. Bavoil
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Anup Mahurkar
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Garry S. A. Myers
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
- * E-mail:
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17
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Brotman RM, Ravel J, Bavoil PM, Gravitt PE, Ghanem KG. Microbiome, sex hormones, and immune responses in the reproductive tract: challenges for vaccine development against sexually transmitted infections. Vaccine 2013; 32:1543-52. [PMID: 24135572 DOI: 10.1016/j.vaccine.2013.10.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 08/05/2013] [Accepted: 10/02/2013] [Indexed: 12/24/2022]
Abstract
The female and male reproductive tracts are complex eco-systems where immune cells, hormones, and microorganisms interact. The characteristics of the reproductive tract mucosa are distinct from other mucosal sites. Reproductive tract mucosal immune responses are compartmentalized, unique, and affected by resident bacterial communities and sex hormones. The female and male genital microbiomes are complex environments that fluctuate in response to external and host-associated stimuli. The female vaginal microbiota play an important role in preventing colonization by pathogenic organisms. Sex hormones and their duration of exposure affect the composition and stability of the microbiome as well as systemic and mucosal immune responses. In addition to the characteristics of the pathogen they are targeting, successful vaccines against sexually transmitted pathogens must take into account the differences between the systemic and mucosal immune responses, the compartmentalization of the mucosal immune responses, the unique characteristics of the reproductive tract mucosa, the role of the mucosal bacterial communities, the impact of sex hormones, and the interactions among all of these factors.
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Affiliation(s)
- Rebecca M Brotman
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD, USA.
| | - Patti E Gravitt
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Khalil G Ghanem
- Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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18
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Hovis KM, Mojica S, McDermott JE, Pedersen L, Simhi C, Rank RG, Myers GSA, Ravel J, Hsia RC, Bavoil PM. Genus-optimized strategy for the identification of chlamydial type III secretion substrates. Pathog Dis 2013; 69:213-22. [PMID: 23873765 DOI: 10.1111/2049-632x.12070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 06/10/2013] [Accepted: 07/09/2013] [Indexed: 12/14/2022] Open
Abstract
Among chlamydial virulence factors are the type III secretion (T3S) system and its effectors. T3S effectors target host proteins to benefit the infecting chlamydiae. The assortment of effectors, each with a unique function, varies between species. This variation likely contributes to differences in host specificity and disease severity. A dozen effectors of Chlamydia trachomatis have been identified; however, estimates suggest that more exist. A T3S prediction algorithm, SVM-based Identification and Evaluation of Virulence Effectors (SIEVE), along with a Yersinia surrogate secretion system helped to identify a new T3S substrate, CT082, which rather than functioning as an effector associates with the chlamydial envelope after secretion. SIEVE was modified to improve/expand effector predictions to include all sequenced genomes. Additional adjustments were made to the existing surrogate system whereby the N terminus of putative effectors was fused to a known effector lacking its own N terminus and was tested for secretion. Expansion of effector predictions by cSIEVE and modification of the surrogate system have also assisted in identifying a new T3S substrate from C. psittaci. The expanded predictions along with modifications to improve the surrogate secretion system have enhanced our ability to identify novel species-specific effectors, which upon characterization should provide insight into the unique pathogenic properties of each species.
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Affiliation(s)
- Kelley M Hovis
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD, USA
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19
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Romano JD, de Beaumont C, Carrasco JA, Ehrenman K, Bavoil PM, Coppens I. A novel co-infection model with Toxoplasma and Chlamydia trachomatis highlights the importance of host cell manipulation for nutrient scavenging. Cell Microbiol 2012; 15:619-46. [PMID: 23107293 DOI: 10.1111/cmi.12060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 09/14/2012] [Accepted: 10/20/2012] [Indexed: 12/24/2022]
Abstract
Toxoplasma and Chlamydia trachomatis are obligate intracellular pathogens that have evolved analogous strategies to replicate within mammalian cells. Both pathogens are known to extensively remodel the cytoskeleton, and to recruit endocytic and exocytic organelles to their respective vacuoles. However, how important these activities are for infectivity by either pathogen remains elusive. Here, we have developed a novel co-infection system to gain insights into the developmental cycles of Toxoplasma and C. trachomatis by infecting human cells with both pathogens, and examining their respective ability to replicate and scavenge nutrients. We hypothesize that the common strategies used by Toxoplasma and Chlamydia to achieve development results in direct competition of the two pathogens for the same pool of nutrients. We show that a single human cell can harbour Chlamydia and Toxoplasma. In co-infected cells, Toxoplasma is able to divert the content of host organelles, such as cholesterol. Consequently, the infectious cycle of Toxoplasma progresses unimpeded. In contrast, Chlamydia's ability to scavenge selected nutrients is diminished, and the bacterium shifts to a stress-induced persistent growth. Parasite killing engenders an ordered return to normal chlamydial development. We demonstrate that C. trachomatis enters a stress-induced persistence phenotype as a direct result from being barred from its normal nutrient supplies as addition of excess nutrients, e.g. amino acids, leads to substantial recovery of Chlamydia growth and infectivity. Co-infection of C. trachomatis with slow growing strains of Toxoplasma or a mutant impaired in nutrient acquisition does not restrict chlamydial development. Conversely, Toxoplasma growth is halted in cells infected with the highly virulent Chlamydia psittaci. This study illustrates the key role that cellular remodelling plays in the exploitation of host intracellular resources by Toxoplasma and Chlamydia. It further highlights the delicate balance between success and failure of infection by intracellular pathogens in a co-infection system at the cellular level.
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Affiliation(s)
- Julia D Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, 21205, USA
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20
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Collingro A, Tischler P, Weinmaier T, Penz T, Heinz E, Brunham RC, Read TD, Bavoil PM, Sachse K, Kahane S, Friedman MG, Rattei T, Myers GSA, Horn M. Unity in variety--the pan-genome of the Chlamydiae. Mol Biol Evol 2011; 28:3253-70. [PMID: 21690563 DOI: 10.1093/molbev/msr161] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chlamydiae are evolutionarily well-separated bacteria that live exclusively within eukaryotic host cells. They include important human pathogens such as Chlamydia trachomatis as well as symbionts of protozoa. As these bacteria are experimentally challenging and genetically intractable, our knowledge about them is still limited. In this study, we obtained the genome sequences of Simkania negevensis Z, Waddlia chondrophila 2032/99, and Parachlamydia acanthamoebae UV-7. This enabled us to perform the first comprehensive comparative and phylogenomic analysis of representative members of four major families of the Chlamydiae, including the Chlamydiaceae. We identified a surprisingly large core gene set present in all genomes and a high number of diverse accessory genes in those Chlamydiae that do not primarily infect humans or animals, including a chemosensory system in P. acanthamoebae and a type IV secretion system. In S. negevensis, the type IV secretion system is encoded on a large conjugative plasmid (pSn, 132 kb). Phylogenetic analyses suggested that a plasmid similar to the S. negevensis plasmid was originally acquired by the last common ancestor of all four families and that it was subsequently reduced, integrated into the chromosome, or lost during diversification, ultimately giving rise to the extant virulence-associated plasmid of pathogenic chlamydiae. Other virulence factors, including a type III secretion system, are conserved among the Chlamydiae to variable degrees and together with differences in the composition of the cell wall reflect adaptation to different host cells including convergent evolution among the four chlamydial families. Phylogenomic analysis focusing on chlamydial proteins with homology to plant proteins provided evidence for the acquisition of 53 chlamydial genes by a plant progenitor, lending further support for the hypothesis of an early interaction between a chlamydial ancestor and the primary photosynthetic eukaryote.
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Affiliation(s)
- Astrid Collingro
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
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21
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Carrasco JA, Tan C, Rank RG, Hsia RC, Bavoil PM. Altered developmental expression of polymorphic membrane proteins in penicillin-stressed Chlamydia trachomatis. Cell Microbiol 2011; 13:1014-25. [PMID: 21504531 DOI: 10.1111/j.1462-5822.2011.01598.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Late Chlamydia trachomatis inclusions express each member of the surface-exposed polymorphic membrane protein family (Pmp subtypes A through I) with a reproducible distribution of fully-on, fully-off and intermediate phenotypes. This observation is consistent with observed variable Pmp antibody profiles in C. trachomatis-infected patients and has led to the hypothesis that the pmp gene family forms the basis of a phase variation-like mechanism of antigenic variation. Here we investigate and compare the developmental expression of each of the nine pmp genes under conditions of optimal in vitro growth with that under conditions that promote prolonged survival of chlamydiae when exposed to penicillin-induced stress. We demonstrate that the pmp gene family includes distinct transcriptional units that are differentially expressed along development and differentially responsive to stress. In particular, our results indicate that expression of pmpA, pmpD and pmpI is uniquely unaffected by stress, suggesting that the PmpA, PmpD and PmpI proteins play a critical role in the pathogenesis of C. trachomatis.
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Affiliation(s)
- Jose A Carrasco
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA
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22
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Mitchell CM, Hovis KM, Bavoil PM, Myers GSA, Carrasco JA, Timms P. Comparison of koala LPCoLN and human strains of Chlamydia pneumoniae highlights extended genetic diversity in the species. BMC Genomics 2010; 11:442. [PMID: 20646324 PMCID: PMC3091639 DOI: 10.1186/1471-2164-11-442] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 07/21/2010] [Indexed: 11/28/2022] Open
Abstract
Background Chlamydia pneumoniae is a widespread pathogen causing upper and lower respiratory tract infections in addition to a range of other diseases in humans and animals. Previous whole genome analyses have focused on four essentially clonal (> 99% identity) C. pneumoniae human genomes (AR39, CWL029, J138 and TW183), providing relatively little insight into strain diversity and evolution of this species. Results We performed individual gene-by-gene comparisons of the recently sequenced C. pneumoniae koala genome and four C. pneumoniae human genomes to identify species-specific genes, and more importantly, to gain an insight into the genetic diversity and evolution of the species. We selected genes dispersed throughout the chromosome, representing genes that were specific to C. pneumoniae, genes with a demonstrated role in chlamydial biology and/or pathogenicity (n = 49), genes encoding nucleotide salvage or amino acid biosynthesis proteins (n = 6), and extrachromosomal elements (9 plasmid and 2 bacteriophage genes). Conclusions We have identified strain-specific differences and targets for detection of C. pneumoniae isolates from both human and animal origin. Such characterisation is necessary for an improved understanding of disease transmission and intervention.
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Affiliation(s)
- Candice M Mitchell
- Faculty of Science and Technology, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059, Australia
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Laroucau K, Vorimore F, Sachse K, Vretou E, Siarkou VI, Willems H, Magnino S, Rodolakis A, Bavoil PM. Differential identification of Chlamydophila abortus live vaccine strain 1B and C. abortus field isolates by PCR-RFLP. Vaccine 2010; 28:5653-6. [PMID: 20600479 DOI: 10.1016/j.vaccine.2010.06.064] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/03/2010] [Accepted: 06/21/2010] [Indexed: 11/28/2022]
Abstract
Comparative genomic analysis of a wild-type strain of the ovine pathogen Chlamydophila abortus and its nitrosoguanidine-induced, temperature-sensitive and virulence-attenuated live vaccine derivative identified point mutations unique to the mutant (Burall et al. [1]). Here, we evaluate the capacity of some of these mutations to either create or eliminate restriction sites using the wild-type strain C. abortus S26/3 as a reference. Three of eight genomic sites with confirmed point mutations (CAB153, CAB636 and CAB648) were retained for analysis as each resulted in the loss of a restriction site in the genome sequence of the vaccine strain. PCR-restriction fragment length polymorphism analysis using restriction enzymes chosen to specifically target the three genomic sites was then applied to a large number of C. abortus field isolates and reference strains. Our results indicate that the three mutations are uniquely present in the vaccine strain, and as such provide easy-to-use markers for the differential identification of the vaccine strain and wild-type isolates.
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Affiliation(s)
- Karine Laroucau
- Unité Zoonoses Bactériennes, Agence Française de Sécurité Sanitaire des Aliments (Lerpaz), 23 Avenue du Général de Gaulle, 94706 Maisons-Alfort Cedex, France.
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Tan C, Hsia RC, Shou H, Carrasco JA, Rank RG, Bavoil PM. Variable expression of surface-exposed polymorphic membrane proteins in in vitro-grown Chlamydia trachomatis. Cell Microbiol 2010; 12:174-87. [PMID: 19811502 PMCID: PMC3073146 DOI: 10.1111/j.1462-5822.2009.01389.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [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] [Indexed: 11/29/2022]
Abstract
The hypothesized variable expression of polymorphic membrane proteins (PmpA-PmpI) in Chlamydia trachomatis-infected patients was tested by examination of the expression of each Pmp subtype in in vitro-grown C. trachomatis. A panel of monospecific polyclonal and monoclonal antibodies was used to demonstrate surface exposure of Pmps of each subtype by differential immunofluorescence (IF) with and without prior detergent permeabilization of paraformaldehyde-fixed inclusions and for selected Pmps by immunogold labelling. Although specific transcript was detected for each pmp gene late in development, IF experiments with Pmp subtype-specific antibodies reveal that a number of inclusions in a single infection do not express Pmps of a given subtype. Coexpression experiments suggest that pmp genes are shut off independently from one another in non-expressing inclusions, i.e. different inclusions are switched off for different Pmps. Overall, these studies establish the existence of an efficient shutoff mechanism independently affecting the expression of each member of the pmp gene family in in vitro-grown C. trachomatis. Like other paralogous gene families of bacterial pathogens, the pmp gene family of C. trachomatis may serve the critical dual function of a highly adaptable virulence factor also providing antigenic diversity in the face of the host adaptive immune response.
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Affiliation(s)
- Chun Tan
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201
| | - Ru-ching Hsia
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201
| | - Huizhong Shou
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201
| | - Jose A. Carrasco
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201
| | - Roger G. Rank
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences and Arkansas Children's Hospital Research Institute, 1120 Marshall St., Little Rock, AR, 72202, USA
| | - Patrik M. Bavoil
- Department of Microbial Pathogenesis, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201
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Tan C, Hsia RC, Shou H, Haggerty CL, Ness RB, Gaydos CA, Dean D, Scurlock AM, Wilson DP, Bavoil PM. Chlamydia trachomatis-infected patients display variable antibody profiles against the nine-member polymorphic membrane protein family. Infect Immun 2009; 77:3218-26. [PMID: 19487469 PMCID: PMC2715660 DOI: 10.1128/iai.01566-08] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [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] [Received: 12/23/2008] [Revised: 03/04/2009] [Accepted: 05/17/2009] [Indexed: 11/20/2022] Open
Abstract
Genomic analysis of the Chlamydiaceae has revealed a multigene family encoding large, putatively autotransported polymorphic membrane proteins (Pmps) with nine members in the sexually transmitted pathogen Chlamydia trachomatis. While various pathogenesis-related functions are emerging for the Pmps, observed genotypic and phenotypic variation among several chlamydial Pmps in various Chlamydia species has led us to hypothesize that the pmp gene repertoire is the basis of a previously undetected mechanism of antigenic variation. To test this hypothesis, we chose to examine the serologic response of C. trachomatis-infected patients to each Pmp subtype. Immune serum samples were collected from four populations of patients with confirmed C. trachomatis genital infection: 40 women with pelvic inflammatory disease from Pittsburgh, PA; 27 and 34 adolescent/young females from Oakland, CA, and Little Rock, AR, respectively; and 58 adult male patients from Baltimore, MD. The Pmp-specific antibody response was obtained using immunoblot analysis against each of the nine recombinantly expressed Pmps and quantified by densitometry. Our results show that nearly all C. trachomatis-infected patients mount a strong serologic response against individual or multiple Pmp subtypes and that the antibody specificity profile varies between patients. Moreover, our analysis reveals differences in the strengths and specificities of the Pmp subtype-specific antibody reactivity relating to gender and clinical outcome. Overall, our results indicate that the Pmps elicit various serologic responses in C. trachomatis-infected patients and are consistent with the pmp gene family being the basis of a mechanism of antigenic variation.
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Affiliation(s)
- Chun Tan
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, 21201, USA
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26
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Wilson DP, Bowlin AK, Bavoil PM, Rank RG. Ocular pathologic response elicited by Chlamydia organisms and the predictive value of quantitative modeling. J Infect Dis 2009; 199:1780-9. [PMID: 19419335 DOI: 10.1086/599093] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [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: 01/31/2024] Open
Abstract
BACKGROUND Chlamydia organisms are a significant cause of ocular and genital tract disease worldwide. Acute inflammatory responses are largely responsible for pathologic changes. METHODS Guinea pigs were inoculated in the conjunctiva with various infectious doses of Chlamydia caviae. We developed a predictive model and thresholds of the ocular pathologic response, on the basis of measurements of the pathologic response and chlamydial inclusion-forming unit (ifu) loads, using statistical and mathematical techniques. We validated the predictions by modifying the pathologic response with the use of a lytic chlamydiaphage. RESULTS If the area under the inclusion-forming unit curve reaches approximately 4x10(5) "ifu-days," then it is likely that an ocular pathologic response will develop and that a serious pathologic finding can develop quickly. The earlier that a pathologic response arises, the longer it will remain. A 2-log10 reduction in the peak inclusion-forming unit load reduces the chance of any pathologic finding emerging from 81% to 32%, and it reduces the chance of a serious pathologic finding emerging from 33% to 2%. A reduction in the peak chlamydial load also substantially reduces the duration of the pathologic response. CONCLUSIONS Our predictive model can be used to evaluate the likely effect of interventions that modify the course of chlamydial infection. It suggests that, to be effective in preventing or mitigating pathologic responses, an intervention is required to change the chlamydial time course before the peak inclusion-forming unit load is reached.
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Affiliation(s)
- David P Wilson
- National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales, Sydney, New South Wales, Australia.
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Abstract
Members of Chlamydiaceae have been extensively characterized by complete genome sequencing. This information provides new understanding concerning their natural evolutionary history. Comparative genome analysis is consistent with the conclusion that host-divergent strains of Chlamydiae are closely related biologically and ecologically. The previous taxonomic separation of the genus based on ribosomal sequences is neither consistent with the natural history of the organism revealed by genome comparisons, nor widely used by the Chlamydia research community 8 years after its introduction; thus, it is proposed to reunite the Chlamydiaceae into a single genus, Chlamydia.
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Yousef Mohamad K, Roche SM, Myers G, Bavoil PM, Laroucau K, Magnino S, Laurent S, Rasschaert D, Rodolakis A. Preliminary phylogenetic identification of virulent Chlamydophila pecorum strains. Infect Genet Evol 2008; 8:764-71. [PMID: 18707024 DOI: 10.1016/j.meegid.2008.06.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 06/18/2008] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
Abstract
Chlamydophila pecorum is an obligate intracellular bacterium associated with different pathological conditions in ruminants, swine and koala, which is also found in the intestine of asymptomatic animals. A multi-virulence locus sequence typing (MVLST) system was developed using 19 C. pecorum strains (8 pathogenic and 11 non-pathogenic intestinal strains) isolated from ruminants of different geographical origins. To evaluate the ability of MVLST to distinguish the pathogenic from the non-pathogenic strains of C. pecorum, the sequences of 12 genes were analysed: 6 potential virulence genes (ompA, incA, incB, incC, mip and copN), 5 housekeeping genes (recA, hemD, aroC, efp, gap), and the ORF663 gene encoding a hypothetical protein (HP) that includes a variant 15-nucleotides coding tandem repeat (CTR). MVLST provided high discriminatory power (100%) in allowing to distinguish 6 of 8 pathogenic strains in a single group, and overall more discriminatory than MLST targeting housekeeping genes. ompA was the most polymorphic gene and the phylogenetic tree based only on its sequence differentiated 4 groups with high bootstrap values. The number of CTRs (rich in serine, proline and lysine) in ORF663 detected in the pathogenic strains was generally lower than that found in the intestinal strains. MVLST appears to be a promising method for the differential identification of virulent C. pecorum strains, and the ompA, incA and ORF663 genes appear to be good molecular markers for further epidemiological investigation of C. pecorum.
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Mohamad KY, Rekiki A, Myers G, Bavoil PM, Rodolakis A. Identification and characterisation of coding tandem repeat variants inincAgene ofChlamydophila pecorum. Vet Res 2008; 39:56. [DOI: 10.1051/vetres:2008032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 07/23/2008] [Indexed: 12/28/2022] Open
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Hoare A, Timms P, Bavoil PM, Wilson DP. Spatial constraints within the chlamydial host cell inclusion predict interrupted development and persistence. BMC Microbiol 2008; 8:5. [PMID: 18182115 PMCID: PMC2254404 DOI: 10.1186/1471-2180-8-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 01/09/2008] [Indexed: 11/10/2022] Open
Abstract
Background The chlamydial developmental cycle involves the alternation between the metabolically inert elementary body (EB) and the replicating reticulate body (RB). The triggers that mediate the interchange between these particle types are unknown and yet this is crucial for understanding basic Chlamydia biology. Presentation of the hypothesis We have proposed a hypothesis to explain key chlamydial developmental events whereby RBs are replicating strictly whilst in contact with the host cell membrane-derived inclusion via type three secretion (T3S) injectisomes. As the inclusion expands, the contact between each RB and the inclusion membrane decreases, eventually reaching a threshold, beyond which T3S is inactivated upon detachment and this is the signal for RB-to-EB differentiation. Testing the hypothesis We explore this hypothesis through the development of a detailed mathematical model. The model uses knowledge and data of the biological system wherever available and simulates the chlamydial developmental cycle under the assumptions of the hypothesis in order to predict various outcomes and implications under a number of scenarios. Implications of the hypothesis We show that the concept of in vitro persistent infection is not only consistent with the hypothesis but in fact an implication of it. We show that increasing the RB radius, and/or the maximum length of T3S needles mediating contact between RBs and the inclusion membrane, and/or the number of inclusions per infected cell, will contribute to the development of persistent infection. The RB radius is the most important determinant of whether persistent infection would ensue, and subsequently, the magnitude of the EB yield. We determine relationships between the length of the T3S needle and the RB radius within an inclusion, and between the RB radius and the number of inclusions per host cell to predict whether persistent infection or normal development would occur within a host cell. These results are all testable experimentally and could lead to significantly greater understanding of one of the most crucial steps in chlamydial development.
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Affiliation(s)
- Alexander Hoare
- National Centre in HIV Epidemiology and Clinical Research, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
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Peters J, Wilson DP, Myers G, Timms P, Bavoil PM. Type III secretion à la Chlamydia. Trends Microbiol 2007; 15:241-51. [PMID: 17482820 DOI: 10.1016/j.tim.2007.04.005] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [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: 12/15/2006] [Revised: 03/07/2007] [Accepted: 04/23/2007] [Indexed: 01/08/2023]
Abstract
Type III secretion (T3S) is a mechanism that is central to the biology of the Chlamydiaceae and many other pathogens whose virulence depends on the translocation of toxic effector proteins to cytosolic targets within infected eukaryotic cells. Biomathematical simulations, using a previously described model of contact-dependent, T3S-mediated chlamydial growth and late differentiation, suggest that chlamydiae contained in small non-fusogenic inclusions will persist. Here, we further discuss the model in the context of in vitro-persistent, stress-induced aberrantly enlarged forms and of recent studies using small molecule inhibitors of T3S. A general mechanism is emerging whereby both early- and mid-cycle T3S-mediated activities and late T3S inactivation upon detachment of chlamydiae from the inclusion membrane are crucial for chlamydial intracellular development.
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Affiliation(s)
- Jan Peters
- Department of Biomedical Sciences, University of Maryland, Baltimore, MD 21201, USA
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32
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Burall LS, Liu Z, Rank R, Bavoil PM. The chlamydial invasin-like protein gene conundrum. Microbes Infect 2007; 9:873-80. [PMID: 17533147 PMCID: PMC2975035 DOI: 10.1016/j.micinf.2007.03.006] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 03/08/2007] [Accepted: 03/09/2007] [Indexed: 10/23/2022]
Abstract
Variants of an ilp (invasin-like protein) gene have been identified previously in Chlamydia caviae and in Chlamydia suis. The C. caviae ilp gene is interrupted by two frame shift mutations while the C. suis gene is intact. Characterization of the ilp gene in C. caviae passaged minimally in vitro showed that the two frameshift mutations were present in the original isolates. The gentamicin protection assay was used to determine if E. coli bacteria expressing the intact C. suis ilp could adhere to or invade HEp-2 cells. While inv+ clones showed increased adherence and invasion, no increase in adherence or invasion was observed for ilp+ clones. However, these clones were found to produce detectable amounts of ilp transcript. In a 48 h time course of C. suis culture, ilp transcript was initially detected at 8 h, peaked at 16 h, and declined subsequently. Antibodies specifically recognizing the putative functional domain of Ilp failed to detect any ilp-specific gene product in either E. coli or C. suis cultures. These data suggest that ilp does not encode a functional protein and raise questions about how ilp was introduced and maintained in Chlamydia.
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Affiliation(s)
- Laurel S Burall
- Department of Biomedical Sciences, University of Maryland Baltimore, Dental School, 666 W. Baltimore St., Baltimore, MD 21201, USA
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Liu Z, Rank R, Kaltenboeck B, Magnino S, Dean D, Burall L, Plaut RD, Read TD, Myers G, Bavoil PM. Genomic plasticity of the rrn-nqrF intergenic segment in the Chlamydiaceae. J Bacteriol 2006; 189:2128-32. [PMID: 17158668 PMCID: PMC1855709 DOI: 10.1128/jb.00378-06] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [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
In Chlamydiaceae, the nucleotide sequence between the 5S rRNA gene and the gene for subunit F of the Na(+)-translocating NADH-quinone reductase (nqrF or dmpP) has varied lengths and gene contents. We analyzed this site in 45 Chlamydiaceae strains having diverse geographical and pathological origins and including members of all nine species.
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Affiliation(s)
- Zhi Liu
- Department of Biomedical Sciences, University of Maryland, Baltimore, MD 21201, USA
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Wilson DP, Timms P, McElwain DLS, Bavoil PM. Type III secretion, contact-dependent model for the intracellular development of chlamydia. Bull Math Biol 2006; 68:161-78. [PMID: 16794925 DOI: 10.1007/s11538-005-9024-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [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: 01/11/2004] [Accepted: 04/08/2005] [Indexed: 10/25/2022]
Abstract
The medically significant genus Chlamydia is a class of obligate intracellular bacterial pathogens that replicate within vacuoles in host eukaryotic cells termed inclusions. Chlamydia's developmental cycle involves two forms; an infectious extracellular form, known as an elementary body (EB), and a non-infectious form, known as the reticulate body (RB), that replicates inside the vacuoles of the host cells. The RB surface is covered in projections that are in intimate contact with the inclusion membrane. Late in the developmental cycle, these reticulate bodies differentiate into the elementary body form. In this paper, we present a hypothesis for the modulation of these developmental events involving the contact-dependent type III secretion (TTS) system. TTS surface projections mediate intimate contact between the RB and the inclusion membrane. Below a certain number of projections, detachment of the RB provides a signal for late differentiation of RB into EB. We use data and develop a mathematical model investigating this hypothesis. If the hypothesis proves to be accurate, then we have shown that increasing the number of inclusions per host cell will increase the number of infectious progeny EB until some optimal number of inclusions. For more inclusions than this optimum, the infectious yield is reduced because of spatial restrictions. We also predict that a reduction in the number of projections on the surface of the RB (and as early as possible during development) will significantly reduce the burst size of infectious EB particles. Many of the results predicted by the model can be tested experimentally and may lead to the identification of potential targets for drug design.
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Affiliation(s)
- D P Wilson
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia.
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Abstract
Chlamydia is a rampant sexually transmitted disease, the world's leading cause of preventable blindness and a possible contributor to heart disease. Recent discoveries are suggesting new ways to curtail its spread
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Read TD, Myers GSA, Brunham RC, Nelson WC, Paulsen IT, Heidelberg J, Holtzapple E, Khouri H, Federova NB, Carty HA, Umayam LA, Haft DH, Peterson J, Beanan MJ, White O, Salzberg SL, Hsia RC, McClarty G, Rank RG, Bavoil PM, Fraser CM. Genome sequence of Chlamydophila caviae (Chlamydia psittaci GPIC): examining the role of niche-specific genes in the evolution of the Chlamydiaceae. Nucleic Acids Res 2003; 31:2134-47. [PMID: 12682364 PMCID: PMC153749 DOI: 10.1093/nar/gkg321] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.3] [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: 11/14/2022] Open
Abstract
The genome of Chlamydophila caviae (formerly Chlamydia psittaci, GPIC isolate) (1 173 390 nt with a plasmid of 7966 nt) was determined, representing the fourth species with a complete genome sequence from the Chlamydiaceae family of obligate intracellular bacterial pathogens. Of 1009 annotated genes, 798 were conserved in all three other completed Chlamydiaceae genomes. The C.caviae genome contains 68 genes that lack orthologs in any other completed chlamydial genomes, including tryptophan and thiamine biosynthesis determinants and a ribose-phosphate pyrophosphokinase, the product of the prsA gene. Notable amongst these was a novel member of the virulence-associated invasin/intimin family (IIF) of Gram-negative bacteria. Intriguingly, two authentic frameshift mutations in the ORF indicate that this gene is not functional. Many of the unique genes are found in the replication termination region (RTR or plasticity zone), an area of frequent symmetrical inversion events around the replication terminus shown to be a hotspot for genome variation in previous genome sequencing studies. In C.caviae, the RTR includes several loci of particular interest including a large toxin gene and evidence of ancestral insertion(s) of a bacteriophage. This toxin gene, not present in Chlamydia pneumoniae, is a member of the YopT effector family of type III-secreted cysteine proteases. One gene cluster (guaBA-add) in the RTR is much more similar to orthologs in Chlamydia muridarum than those in the phylogenetically closest species C.pneumoniae, suggesting the possibility of horizontal transfer of genes between the rodent-associated Chlamydiae. With most genes observed in the other chlamydial genomes represented, C.caviae provides a good model for the Chlamydiaceae and a point of comparison against the human atherosclerosis-associated C.pneumoniae. This crucial addition to the set of completed Chlamydiaceae genome sequences is enabling dissection of the roles played by niche-specific genes in these important bacterial pathogens.
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Affiliation(s)
- T D Read
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
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Read TD, Fraser CM, Hsia RC, Bavoil PM. Comparative analysis of Chlamydia bacteriophages reveals variation localized to a putative receptor binding domain. Microb Comp Genomics 2001; 5:223-31. [PMID: 11471835 DOI: 10.1089/omi.1.2000.5.223] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Three recently discovered ssDNA Chlamydia-infecting microviruses, phiCPG1, phiAR39, and Chp2, were compared with the previously characterized phage from avian C. psittaci, Chp1. Although the four bacteriophages share an identical arrangement of their five main genes, Chpl has diverged significantly in its nucleotide and protein sequences from the other three, which form a closely related group. The VP1 major viral capsid proteins of phiCPG1 and phiAR39 (from guinea pig-infecting C. psittaci and C. pneumoniae, respectively) are almost identical. However, VP1 of ovine C. psittaci phage Chp2 shows a high rate of nucleotide sequence change localized to a region encoding the "IN5" loop of the protein, thought to be a potential receptor-binding site. Phylogenetic analysis suggests that the ORF4 replication initiation protein is evolving faster than the other phage proteins. phiCPG1, phiAR39, and Chp2 are closely related to an ORF4 homolog inserted in the C. pneumoniae chromosome. This sequence analysis opens the way toward understanding the host-range and evolutionary history of these phages.
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Affiliation(s)
- T D Read
- The Institute for Genomic Research, Rockville, Maryland 20851, USA.
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Schachter J, Stephens RS, Timms P, Kuo C, Bavoil PM, Birkelund S, Boman J, Caldwell H, Campbell LA, Chernesky M, Christiansen G, Clarke IN, Gaydos C, Grayston JT, Hackstadt T, Hsia R, Kaltenboeck B, Leinonnen M, Ojcius D, Ocjius D, McClarty G, Orfila J, Peeling R, Puolakkainen M, Quinn TC, Rank RG, Raulston J, Ridgeway GL, Saikku P, Stamm WE, Taylor-Robinson DT, Wang SP, Wyrick PB. Radical changes to chlamydial taxonomy are not necessary just yet. Int J Syst Evol Microbiol 2001; 51:249. [PMID: 11211265 DOI: 10.1099/00207713-51-1-249] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Affiliation(s)
- Patrik M Bavoil
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK1
| | - Ru-Ching Hsia
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK1
| | - David M Ojcius
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, 75724 Paris Cedex 15, France2
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Hsia RC, Ting LM, Bavoil PM. Microvirus of chlamydia psittaci strain guinea pig inclusion conjunctivitis: isolation and molecular characterization. Microbiology (Reading) 2000; 146 ( Pt 7):1651-1660. [PMID: 10878129 DOI: 10.1099/00221287-146-7-1651] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The authors report the isolation and molecular characterization of a bacteriophage, φCPG1, which infects CHLAMYDIA: psittaci strain Guinea pig Inclusion Conjunctivitis. Purified virion preparations contained isometric particles of 25 nm diameter, superficially similar to spike-less members of the φX174 family of bacteriophages. The single-stranded circular DNA genome of φCPG1 included five large ORFs, which were similar to ORFs in the genome of a previously described CHLAMYDIA: bacteriophage (Chp1) that infects avian C. psittaci. Three of the ORFs encoded polypeptides that were similar to those in a phage infecting the mollicute Spiroplasma melliferum, a pathogen of honeybees. Lesser sequence similarities were seen between two ORF products and the major capsid protein of the φX174 coliphage family and proteins mediating rolling circle replication initiation in phages, phagemids and plasmids. Phage φCPG1 is the second member of the genus CHLAMYDIAMICROVIRUS:, the first to infect a member of a CHLAMYDIA: species infecting mammals. Similarity searches of the nucleotide sequence further revealed a highly conserved (75% identity) 375 base sequence integrated into the genome of the human pathogen Chlamydia pneumoniae. This genomic segment encodes a truncated 113 residue polypeptide, the sequence of which is 72% identical to the amino-terminal end of the putative replication initiation protein of φCPG1. This finding suggests that C. pneumoniae has been infected by a phage related to φCPG1 and that infection resulted in integration of some of the phage genome into the C. pneumoniae genome.
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Affiliation(s)
- Ru-Ching Hsia
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK1
| | - Li-Min Ting
- Department of Medicine, University of California at San Francisco, Box 0868, San Francisco,CA 94143-0868, USA2
| | - Patrik M Bavoil
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK1
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Hsia R, Ohayon H, Gounon P, Dautry-Varsat A, Bavoil PM. Phage infection of the obligate intracellular bacterium, Chlamydia psittaci strain guinea pig inclusion conjunctivitis. Microbes Infect 2000; 2:761-72. [PMID: 10955956 DOI: 10.1016/s1286-4579(00)90356-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [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: 10/18/2022]
Abstract
The infectious cycle of phiCPG1, a bacteriophage that infects the obligate intracellular pathogen, Chlamydia psittaci strain Guinea Pig Inclusion Conjunctivitis, was observed using transmission electron microscopy of phage-hyperinfected, Chlamydia-infected HeLa cells. Phage attachment to extracellular, metabolically dormant, infectious elementary bodies and cointernalisation are demonstrated. Following entry, phage infection takes place as soon as elementary bodies differentiate into metabolically active reticulate bodies. Phage-infected bacteria follow an altered developmental path whereby cell division is inhibited, producing abnormally large reticulate bodies, termed maxi-reticulate bodies, which do not mature to elementary bodies. These forms eventually lyse late in the chlamydial developmental cycle, releasing abundant phage progeny in the inclusion and, upon lysis of the inclusion membrane, into the cytosol of the host cell. Structural integrity of the hyperinfected HeLa cell is markedly compromised at late stages. Released phage particles attach avidly to the outer leaflet of the outer membranes of lysed and unlysed Chlamydiae at different stages of development, suggesting the presence of specific phage receptors in the outer membrane uniformly during the chlamydial developmental cycle. A mechanism for phage infection is proposed, whereby phage gains access to replicating chlamydiae by attaching to the infectious elementary body, subsequently subverting the chlamydial developmental cycle to its own replicative needs. The implications of phage infection in the context of chlamydial infection and disease are discussed.
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Affiliation(s)
- R Hsia
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, UK
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Abstract
Four genes of Chlamydia psittaci strain guinea pig inclusion conjunctivitis (GPIC), whose predicted products are highly homologous to structural and regulatory components of a contact-dependent or type III secretion apparatus, were isolated. Related to genes present in several animal and plant bacterial pathogens, these genes may represent a section of a previously undetected chromosomal virulence locus analogous to several recently described virulence-associated type III secretion loci. The existence of contact-dependent secretion in Chlamydia strongly suggests that these bacteria use pathogenic mechanisms that are similar to those of other intracellular bacterial pathogens. Unlike other intracellular bacteria, however, chlamydiae are metabolically inactive extracellularly and only become capable of global protein synthesis several hours after infection. This implies that chlamydial contact-dependent secretion is only active from within, uniquely after the bacteria have been internalized by eukaryotic cells. The possible role(s) of this pathway in chlamydial pathogenesis are discussed.
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Affiliation(s)
- R C Hsia
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, UK.
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Gutiérrez-Martín CB, Ojcius DM, Hsia R, Hellio R, Bavoil PM, Dautry-Varsat A. Heparin-mediated inhibition of Chlamydia psittaci adherence to HeLa cells. Microb Pathog 1997; 22:47-57. [PMID: 9032762 DOI: 10.1006/mpat.1996.0090] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [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] [Indexed: 02/03/2023]
Abstract
The adherence of human strains of Chlamydia trachomatis has been recently shown to be inhibitable by heparin and heparitinase, leading to the proposal that Chlamydia binding to host cells may be mediated by a glycosaminoglycan (GAG)-dependent mechanism. We here describe the adherence of the guinea-pig pathogen, Chlamydia psittaci GPIC, to HeLa cells, which was measured by cytofluorometry with chlamydiae whose DNA was fluorescently labelled. Adherence could be inhibited by heat or trypsin pretreatment of the bacteria, and binding was much faster at 37 degrees C (reaching a plateau within 1 h) than 4 degrees C. Little binding remained when host cells were pre-fixed with paraformaldehyde, suggesting that host cell receptor mobility may be required for effective adherence. Visualization by confocal microscopy confirmed that the bacteria were at or near the host cell surface during the entire time-course of these experiments. Adherence increased as a function of pH between pH 6 and pH 8.0-8.5. Both adherence and infection of HeLa cells could be inhibited with heparin when the adherence step was performed at 4 degrees C, but only infection was inhibited when the adherence step was performed at 37 degrees C, even though heparitinase could block adherence at either 4 degrees C or 37 degrees C. Even at 4 degrees C, heparin-mediated inhibition was significantly lower at pH 8 than pH 7.4, suggesting that GAG-independent mechanisms may play a role in the higher adherence observed at basic pH. These results therefore demonstrate that a GAG-dependent adherence step may be operative in C. psittaci, and raise the possibility that other adherence mechanisms may also contribute to binding by this chlamydial strain. Furthermore, they suggest that there may not be a strict correlation between C. psittaci adherence and the ability to cause productive infections.
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Affiliation(s)
- C B Gutiérrez-Martín
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, CNRS URA, 1960, 75724 Paris
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Hsia RC, Bavoil PM. Homologs of Escherichia coli recJ, gltX and of a putative 'early' gene of avian Chlamydia psittaci are located upstream of the 'late' omp2 locus of Chlamydia psittaci strain guinea pig inclusion conjunctivitis. Gene 1996; 176:163-9. [PMID: 8918248 DOI: 10.1016/0378-1119(96)00240-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 02/03/2023]
Abstract
The nucleotide sequence of nearly 6 kb of genomic DNA located immediately upstream of the omp3-omp2 operon of Chlamydia psittaci strain GPIC was obtained, revealing four significant open reading frames (ORFs), named ORF1, ORF2, ORF4 and ORF5. Searches for homologous sequences in the GenBank/EMBL databases have revealed that: (a) the open-ended ORF1 putatively encodes an homolog of RecJ of Escherichia coli, thought to be required for RecBCD-independent and conjugational recombination, and for UV repair; (b) the predicted translation product of ORF4 is highly homologous to the putative product of EUO, a previously described ORF of avian C. psittaci strain 6BC which is preferentially transcribed early during the life cycle; and (c) ORF5 putatively encodes an homolog of bacterial glutamyl-tRNA synthetases. This analysis establishes the genetic linkage of late (omp3-omp2) and of a proposed early (EUO) genes in Chlamydia.
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Affiliation(s)
- R C Hsia
- Department of Microbiology and Immunology, University of Rochester Medical Center, NY 14642, USA
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Abstract
The nucleotide sequence of a 3.1-kb genomic DNA fragment carrying the omp3, omp2 and srp gene homologs from Chlamydia psittaci strain GPIC was determined. A comparative analysis of the GPIC sequence with other chlamydial omp2-linked sequences reveals highly conserved omp3 and omp2 upstream sequences across species, suggesting a unified mechanism of transcription regulation. In contrast, the omp2-srp intergenic segment, which encompasses hypothetical srp transcriptional initiation sites, is relatively less conserved in length and in sequence. Examination of the predicted translation products reveals a high degree of homology within Omp3 and Omp2 across species, with the notable exception of the N-terminal fifth of Omp2. Although the latter segment displays relatively high interspecies sequence variation, it includes a smaller segment, whose high positive charge density is conserved across species, suggesting a conserved structure/function. In contrast to Omp2 and Omp3, a comparative analysis of the predicted amino acid (aa) sequence of the srp product reveals high homology within species, but relatively little across species. A 38-aa segment near the C-terminus of Srp, whose sequence is 64% identical between C. psittaci GPIC and C. trachomatis, is partially truncated in C. psittaci 6BC.
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Affiliation(s)
- R C Hsia
- Department of Microbiology and Immunology, University of Rochester Medical Center, NY 14642, USA
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Abstract
HEp-2 cells internalize non-pathogenic Escherichia coli bacteria by a low-efficiency internalization mechanism which is upregulated in Pho-derepressed strains (as shown by Sinai and Bavoil in 1993), and is independent of microfilament integrity but requires functional microtubules. Here, we further characterize the microtubule requirement of this pathway using various effectors of microtubule integrity and function. Furthermore, we show that internalization is enhanced upon treatment with monodansylcadaverine, a specific inhibitor of receptor mediated endocytosis, and is insensitive to brefeldin A, which promotes the microtubule-dependent reorganization of the endosome. An assay system is also described to directly evaluate the contribution of pinocytosis to this pathway based on the ability of the bacteria to cointernalize and consequently colocalize with the fluid-phase marker, Texas-red-conjugated dextran (TRD). Using this assay, Hoescht-stained bacteria were observed in TRD-containing vesicles in numbers that are consistent with their observed internalization rate. Overall, these data are strongly supportive of the existence of a low-efficiency macropinocytic mechanism of entry for these non-pathogenic bacteria. Moreover, the observed requirements for host tyrosine kinase and protein kinase C activities suggest that it is inducible.
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Affiliation(s)
- A P Sinai
- University of Rochester Medical Center, Department of Microbiology and Immunology, NY 14642, USA
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Abstract
The chlamydial life cycle involves the intimate interaction of components of the infectious elementary body (EB) surface with receptors on the susceptible eukaryotic cell plasma membrane. We have developed an in vitro ligand binding assay system for the identification and characterization of detergent-extracted EB envelope proteins capable of binding to glutaraldehyde-fixed HeLa cell surfaces. With this assay, the developmentally regulated cysteine-rich envelope protein Omp2 of Chlamydia psittaci strain guinea pig inclusion conjunctivitis was shown to bind specifically to HeLa cells. HeLa cells bound Omp2 selectively over other cell wall-associated proteins, including the major outer membrane protein, and the binding of Omp2 was abolished under conditions which alter its conformation. Furthermore, trypsin treatment, which reduces EB adherence, resulted in the proteolytic removal of a small terminal peptide of Omp2 at the EB surface and inactivated Omp2 in the ligand binding assay, while having a negligible effect on the major outer membrane protein. Collectively, our results suggest that Omp2 possesses the capacity to engage in a specific interaction with the host eukaryotic cell. We speculate that, since Omp2 is present only in the infectious EB form, the observed in vitro interaction may be representative of a determining step of the chlamydial pathogenic process.
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Affiliation(s)
- L M Ting
- Department of Microbiology and Immunology, University of Rochester Medical Center, New York 14642, USA
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Rank RG, Dascher C, Bowlin AK, Bavoil PM. Systemic immunization with Hsp60 alters the development of chlamydial ocular disease. Invest Ophthalmol Vis Sci 1995; 36:1344-51. [PMID: 7775112] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE To determine whether immunization with recombinant Hsp60 would exacerbate ocular pathology on challenge with viable chlamydial elementary bodies. METHODS Guinea pigs were immunized either subcutaneously with recombinant Hsp60 or both subcutaneously with recombinant Hsp60 and ocularly with attenuated Salmonella typhimurium expressing the guinea pig inclusion conjunctivitis (GPIC) Hsp60 antigen. All animals were challenged in the conjunctiva with the agent of GPIC, and the degree of gross ocular pathology was determined. Immunoglobulin G (IgG) and immunoglobulin A (IgA) antibody titers to Hsp60 were measured in ocular secretions as a measure of the degree of immunization. RESULTS In primary and challenge GPIC infection, the degree of gross ocular pathology was lower in the immunized group. The presence of high IgA and IgG antibody titers to Hsp60 in tears suggested that the response may have been modified by the presence of blocking antibodies that either may have removed the antigen quickly or prevented interaction with sensitized T cells. In contrast to subcutaneous immunization, the combined immunization regimen, consisting of subcutaneous recombinant Hsp60 followed by ocular inoculation of the attenuated Salmonella, resulted in no difference in gross pathology after reinfection of guinea pigs with GPIC. CONCLUSIONS These data indicated that the immunization with Hsp60 did not produce exacerbated disease on challenge with viable organisms; however, the data suggested that the route of administration, form of antigen, or both may be critical in the disease process.
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Affiliation(s)
- R G Rank
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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