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Mjølnerød EB, Srivastava A, Moore LJ, Plarre H, Nylund A. Identification of housekeeping genes of Candidatus Branchiomonas cysticola associated with epitheliocystis in Atlantic salmon (Salmo salar L.). Arch Microbiol 2022; 204:365. [PMID: 35661924 PMCID: PMC9167185 DOI: 10.1007/s00203-022-02966-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/26/2022]
Abstract
Candidatus Branchiomonas cysticola is an intracellular, gram-negative Betaproteobacteria causing epitheliocystis in Atlantic Salmon (Salmo salar L.). The bacterium has not been genetically characterized at the intraspecific level despite its high prevalence among salmon suffering from gill disease in Norwegian aquaculture. DNA from gill samples of Atlantic salmon PCR positive for Cand. B. cysticola and displaying pathological signs of gill disease, was, therefore, extracted and subject to next-generation sequencing (mNGS). Partial sequences of four housekeeping (HK) genes (aceE, lepA, rplB, rpoC) were ultimately identified from the sequenced material. Assays for real-time RT-PCR and fluorescence in-situ hybridization, targeting the newly acquired genes, were simultaneously applied with existing assays targeting the previously characterized 16S rRNA gene. Agreement in both expression and specificity between these putative HK genes and the 16S gene was observed in all instances, indicating that the partial sequences of these HK genes originate from Cand. B. cysticola. The knowledge generated from the present study constitutes a major prerequisite for the future design of novel genotyping schemes for this bacterium.
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Affiliation(s)
- Even Bysveen Mjølnerød
- Department of Biological Sciences, Fish Disease Research Group, University of Bergen, PO Box 7803, 5020, Bergen, Norway.
| | - Aashish Srivastava
- Department of Clinical Science, University of Bergen, PO Box 7804, 5020, Bergen, Norway
| | - Lindsey J Moore
- Department of Biological Sciences, Fish Disease Research Group, University of Bergen, PO Box 7803, 5020, Bergen, Norway
| | - Heidrun Plarre
- Department of Biological Sciences, Fish Disease Research Group, University of Bergen, PO Box 7803, 5020, Bergen, Norway
| | - Are Nylund
- Department of Biological Sciences, Fish Disease Research Group, University of Bergen, PO Box 7803, 5020, Bergen, Norway
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2
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Cascarano MC, Ruetten M, Vaughan L, Tsertou MI, Georgopoulou D, Keklikoglou K, Papandroulakis N, Katharios P. Epitheliocystis in Greater Amberjack: Evidence of a Novel Causative Agent, Pathology, Immune Response and Epidemiological Findings. Microorganisms 2022; 10:627. [PMID: 35336202 PMCID: PMC8949381 DOI: 10.3390/microorganisms10030627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 01/03/2023] Open
Abstract
Epitheliocystis is a fish gill disease caused by a broad range of intracellular bacteria infecting freshwater and marine fish worldwide. Here we report the occurrence and progression of epitheliocystis in greater amberjack reared in Crete (Greece). The disease appears to be caused mainly by a novel Betaproteobacteria belonging to the Candidatus Ichthyocystis genus with a second agent genetically similar to Ca. Parilichlamydia carangidicola coinfecting the gills in some cases. After a first detection of the disease in 2017, we investigated epitheliocystis in the following year's cohort of greater amberjack juveniles (cohort 2018) transferred from inland tanks to the same cage farm in the open sea where the first outbreak was detected. This cohort was monitored for over a year together with stocks of gilthead seabream and meagre co-farmed in the same area. Our observations showed that epitheliocystis could be detected in greater amberjack gills as early as a month following the transfer to sea cages, with ionocytes at the base of the gill lamellae being initially infected. Cyst formation appears to trigger a proliferative response, leading to the fusion of lamellae, impairment of gill functions and subsequently to mortality. Lesions are characterized by infiltration of immune cells, indicating activation of the innate immune response. At later stages of the outbreak, cysts were no longer found in ionocytes but were observed in mucocytes at the trailing edge of the filament. Whole cysts appeared finally to be expelled from infected mucocytes directly into the water, which might constitute a novel means of dispersion of the infectious agents. Molecular screening indicates that meagre is not affected by this disease and confirms the presence of previously described epitheliocystis agents, Ca. Ichthyocystis sparus, Ca. Ichthyocystis hellenicum and Ca. Similichlamydia spp., in gilthead seabream. Prevalence data show that the bacteria persist in both gilthead seabream and greater amberjack cohorts after first infection.
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Affiliation(s)
- Maria Chiara Cascarano
- Department of Biology, University of Crete, 71003 Heraklion, Greece; (M.C.C.); (K.K.)
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
| | - Maja Ruetten
- Pathovet AG, 8317 Tagelswangen, Switzerland; (M.R.); (L.V.)
| | - Lloyd Vaughan
- Pathovet AG, 8317 Tagelswangen, Switzerland; (M.R.); (L.V.)
| | - Maria Ioanna Tsertou
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
| | - Dimitra Georgopoulou
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
| | - Kleoniki Keklikoglou
- Department of Biology, University of Crete, 71003 Heraklion, Greece; (M.C.C.); (K.K.)
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
| | - Nikos Papandroulakis
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
| | - Pantelis Katharios
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (M.I.T.); (D.G.); (N.P.)
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3
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Dagleish MP, Flockhart AF, Baily JL, Hall AJ, Simpson TI, Longbottom D. Presence of DNA from Chlamydia-like organisms in the nasal cavities of grey seal pups (Halichoerus grypus) and three different substrates present in a breeding colony. BMC Vet Res 2021; 17:328. [PMID: 34645426 PMCID: PMC8515689 DOI: 10.1186/s12917-021-03032-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/27/2021] [Indexed: 12/03/2022] Open
Abstract
Background Chlamydia-like organisms (CLO) have been found to be present in many environmental niches, including human sewage and agricultural run-off, as well as in a number of aquatic species worldwide. Therefore, monitoring their presence in sentinel wildlife species may be useful in assessing the wider health of marine food webs in response to habitat loss, pollution and disease. We used nasal swabs from live (n = 42) and dead (n = 50) pre-weaned grey seal pups and samples of differing natal substrates (n = 8) from an off-shore island devoid of livestock and permanent human habitation to determine if CLO DNA is present in these mammals and to identify possible sources. Results We recovered CLO DNA from 32/92 (34.7%) nasal swabs from both live (n = 17) and dead (n = 15) seal pups that clustered most closely with currently recognised species belonging to three chlamydial families: Parachlamydiaceae (n = 22), Rhabdochlamydiaceae (n = 6), and Simkaniaceae (n = 3). All DNA positive sediment samples (n = 7) clustered with the Rhabdochlamydiaceae. No difference was found in rates of recovery of CLO DNA in live versus dead pups suggesting the organisms are commensal but their potential as opportunistic secondary pathogens could not be determined. Conclusion This is the first report of CLO DNA being found in marine mammals. This identification warrants further investigation in other seal populations around the coast of the UK and in other areas of the world to determine if this finding is unique or more common than shown by this data. Further investigation would also be warranted to determine if they are present as purely commensal organisms or whether they could also be opportunistic pathogens in seals, as well as to investigate possible sources of origin, including whether they originated as a result of anthropogenic impacts, including human waste and agricultural run-off.
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Affiliation(s)
- Mark P Dagleish
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK
| | - Allen F Flockhart
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.,Present address: School of Applied Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh, UK
| | - Johanna L Baily
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.,Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK.,Present address: Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Ailsa J Hall
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
| | - T Ian Simpson
- Biomathematics and Statistics Scotland, JCMB, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, UK.,Present address: School of Informatics, University of Edinburgh, Crichton Street, Edinburgh, UK
| | - David Longbottom
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.
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Novacovsky GN, Palacios MG, Sueiro MC. Epitheliocystis in wild marine fishes and its relation with anthropogenic pollution. JOURNAL OF FISH BIOLOGY 2021; 99:1519-1523. [PMID: 34159586 DOI: 10.1111/jfb.14826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
Epitheliocystis is a fish disease with recorded in increasing numbers globally. Here we show that (a) pollution-exposed wild marine fishes have higher infection prevalence than nonexposed individuals from reference sites, suggesting that anthropogenic pollution predisposes individuals to this disease in natural systems, (b) the effect of pollution on infection status did not vary significantly between two sympatric fish species, and (c) infected and noninfected individuals from both species did not differ significantly in selected immune and general-health parameters, a result that deserves further study with increased sample sizes.
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Affiliation(s)
- Gabriela N Novacovsky
- Centro para el Estudio de Sistemas Marinos, Centro Nacional Patagónico - Consejo Nacional de Investigaciones Científicas y Técnicas), Puerto Madryn, Argentina
| | - María G Palacios
- Centro para el Estudio de Sistemas Marinos, Centro Nacional Patagónico - Consejo Nacional de Investigaciones Científicas y Técnicas), Puerto Madryn, Argentina
| | - María C Sueiro
- Centro para el Estudio de Sistemas Marinos, Centro Nacional Patagónico - Consejo Nacional de Investigaciones Científicas y Técnicas), Puerto Madryn, Argentina
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Zhang XH, Ahmad W, Zhu XY, Chen J, Austin B. Viable but nonculturable bacteria and their resuscitation: implications for cultivating uncultured marine microorganisms. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:189-203. [PMID: 37073345 PMCID: PMC10077291 DOI: 10.1007/s42995-020-00041-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 03/25/2020] [Indexed: 05/03/2023]
Abstract
Culturing has been the cornerstone of microbiology since Robert Koch first successfully cultured bacteria in the late nineteenth century. However, even today, the majority of microorganisms in the marine environment remain uncultivated. There are various explanations for the inability to culture bacteria in the laboratory, including lack of essential nutrients, osmotic support or incubation conditions, low growth rate, development of micro-colonies, and the presence of senescent or viable but nonculturable (VBNC) cells. In the marine environment, many bacteria have been associated with dormancy, as typified by the VBNC state. VBNC refers to a state where bacteria are metabolically active, but are no longer culturable on routine growth media. It is apparently a unique survival strategy that has been adopted by many microorganisms in response to harsh environmental conditions and the bacterial cells in the VBNC state may regain culturability under favorable conditions. The resuscitation of VBNC cells may well be an important way to cultivate the otherwise uncultured microorganisms in marine environments. Many resuscitation stimuli that promote the restoration of culturability have so far been identified; these include sodium pyruvate, quorum sensing autoinducers, resuscitation-promoting factors Rpfs and YeaZ, and catalase. In this review, we focus on the issues associated with bacterial culturability, the diversity of bacteria entering the VBNC state, mechanisms of induction into the VBNC state, resuscitation factors of VBNC cells and implications of VBNC resuscitation stimuli for cultivating these otherwise uncultured microorganisms. Bringing important microorganisms into culture is still important in the era of high-throughput sequencing as their ecological functions in the marine environment can often only be known through isolation and cultivation.
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Affiliation(s)
- Xiao-Hua Zhang
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071 China
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266100 China
| | - Waqar Ahmad
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Xiao-Yu Zhu
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050 China
| | - Brian Austin
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA Scotland, UK
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6
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Oren A, Garrity GM, Parker CT, Chuvochina M, Trujillo ME. Lists of names of prokaryotic Candidatus taxa. Int J Syst Evol Microbiol 2020; 70:3956-4042. [DOI: 10.1099/ijsem.0.003789] [Citation(s) in RCA: 782] [Impact Index Per Article: 195.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We here present annotated lists of names of Candidatus taxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status of Candidatus taxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names of Candidatus taxa with additions and corrections to the current lists to be published periodically in the International Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of the Candidatus names if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.
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Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 9190401 Jerusalem, Israel
| | - George M. Garrity
- NamesforLife, LLC, PO Box 769, Okemos MI 48805-0769, USA
- Department of Microbiology & Molecular Genetics, Biomedical Physical Sciences, Michigan State University, East Lansing, MI 48824-4320, USA
| | | | - Maria Chuvochina
- Australian Centre for Ecogenomics, University of Queensland, St. Lucia QLD 4072, Brisbane, Australia
| | - Martha E. Trujillo
- Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, 37007, Salamanca, Spain
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7
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Tinta T, Kogovšek T, Klun K, Malej A, Herndl GJ, Turk V. Jellyfish-Associated Microbiome in the Marine Environment: Exploring Its Biotechnological Potential. Mar Drugs 2019; 17:E94. [PMID: 30717239 PMCID: PMC6410321 DOI: 10.3390/md17020094] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 12/25/2022] Open
Abstract
Despite accumulating evidence of the importance of the jellyfish-associated microbiome to jellyfish, its potential relevance to blue biotechnology has only recently been recognized. In this review, we emphasize the biotechnological potential of host⁻microorganism systems and focus on gelatinous zooplankton as a host for the microbiome with biotechnological potential. The basic characteristics of jellyfish-associated microbial communities, the mechanisms underlying the jellyfish-microbe relationship, and the role/function of the jellyfish-associated microbiome and its biotechnological potential are reviewed. It appears that the jellyfish-associated microbiome is discrete from the microbial community in the ambient seawater, exhibiting a certain degree of specialization with some preferences for specific jellyfish taxa and for specific jellyfish populations, life stages, and body parts. In addition, different sampling approaches and methodologies to study the phylogenetic diversity of the jellyfish-associated microbiome are described and discussed. Finally, some general conclusions are drawn from the existing literature and future research directions are highlighted on the jellyfish-associated microbiome.
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Affiliation(s)
- Tinkara Tinta
- Department of Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
- Marine Biology Station Piran, National Institute of Biology, Fornače 41, 6330 Piran, Slovenia.
| | - Tjaša Kogovšek
- Marine Biology Station Piran, National Institute of Biology, Fornače 41, 6330 Piran, Slovenia.
| | - Katja Klun
- Marine Biology Station Piran, National Institute of Biology, Fornače 41, 6330 Piran, Slovenia.
| | - Alenka Malej
- Marine Biology Station Piran, National Institute of Biology, Fornače 41, 6330 Piran, Slovenia.
| | - Gerhard J Herndl
- Department of Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, 1790 AB Den Burg, The Netherlands.
| | - Valentina Turk
- Marine Biology Station Piran, National Institute of Biology, Fornače 41, 6330 Piran, Slovenia.
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Blandford MI, Taylor-Brown A, Schlacher TA, Nowak B, Polkinghorne A. Epitheliocystis in fish: An emerging aquaculture disease with a global impact. Transbound Emerg Dis 2018; 65:1436-1446. [PMID: 29790651 DOI: 10.1111/tbed.12908] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 12/11/2022]
Abstract
Epitheliocystis is a skin and gill disease in fish caused by pathogenic intracellular bacteria. The disease has been reported in at least 90 species of marine and freshwater fish in both the southern and northern hemispheres. It affects a number of commercially important aquaculture species, including salmon, kingfish and bream. In infected fish, cysts typically develop in the gill epithelia, promoting the fusion of gill lamellae. Infections can lead to respiratory distress and death, particularly in cultured and juvenile fish with cases rarely reported in wild fish. Modern molecular techniques are challenging the conventional wisdoms regarding the epidemiology of epitheliocystis, showing now that a number of distinct bacterial pathogens from completely different phyla can cause this disease. Here, we review the state of knowledge, including updates on aetiology, host range, diagnosis and treatments. Traditionally, bacteria from the phylum Chlamydiae were the only known pathogenic agents of epitheliocystis, but aetiology is now recognized as being more complex, including a range of Proteobacteria. Notwithstanding recent advances in identifying the pathogens, the reservoirs and modes of transmission remain largely unknown. Recent genome sequencing of the growing number of epitheliocystis agents suggests that many bacteria causing this disease are unique to individual species of fish. Environmental conditions that approach or exceed animals' physiological tolerances (e.g. atypical temperature, salinity or pH levels) are thought to contribute to disease development and progression. Empirical data and evidence concerning epidemiology, aetiology and treatments are, however, in many cases limited, highlighting the need for more work to better characterize this disease across the different hosts and locales affected.
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Affiliation(s)
| | - Alyce Taylor-Brown
- USC Animal Research Centre, University of the Sunshine Coast, Maroochydore D.C., QLD, Australia
| | - Thomas A Schlacher
- USC Animal Research Centre, University of the Sunshine Coast, Maroochydore D.C., QLD, Australia.,School of Science & Engineering, University of the Sunshine Coast, Maroochydore D.C., QLD, Australia
| | - Barbara Nowak
- Institute of Marine and Antarctic Studies, University of Tasmania, Newnham, TAS, Australia
| | - Adam Polkinghorne
- USC Animal Research Centre, University of the Sunshine Coast, Maroochydore D.C., QLD, Australia
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Steigen A, Nylund A, Plarre H, Watanabe K, Karlsbakk E, Brevik Ø. Presence of selected pathogens on the gills of five wrasse species in western Norway. DISEASES OF AQUATIC ORGANISMS 2018; 128:21-35. [PMID: 29565251 DOI: 10.3354/dao03198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The objective of this study was to identify gill pathogens in Labridae (wrasse) species used as cleaner fish to control salmon louse in western Norwegian aquaculture. Wrasse are often moved over long distances, raising issues of fish health, welfare and pathogen transmission. Histological examination and real-time RT-PCR analysis of the gills from Centrolabrus exoletus, Ctenolabrus rupestris, Labrus bergylta, L. mixtus and Symphodus melops revealed several pathogens: a new species of Ichthyobodo, Paramoeba perurans, microsporidia, trichodinids, Hatschekia spp., Candidatus Similichlamydia labri and 2 putative new species of Chlamydiae. Cand. S. labri or closely related bacteria were present on most wrasse specimens. Epitheliocysts on the gills of L. mixtus contained large inclusions (120 µm) with actiniae radiating from the inclusion membrane. A possible member of the Candidatus family Parilichlamydiaceae was present at a high prevalence on the gills of L. mixtus, L. bergylta and C. rupestris. Sequencing the 16S rRNA gene showed 93.9% similarity to Cand. S. labri and 96.8% similarity to Cand. Parilichlamydia carangidicola from the gills of Seriola lalandi. This bacterium probably represents a new species within the order Chlamydiales, family Cand. Parilichlamydiaceae. The other Chlamydiae detected on gills of S. melops could represent a new species in Cand. genus Syngnamydia. Ichthyobodo sp. and Paranucleospora theridion were detected on the gills of nearly all individuals, while Paramoeba spp. were detected on the gills of L. bergylta and L. mixtus. Trichodinids, microsporidia and parasitic copepods had low prevalence. Viral haemorrhagic septicaemia virus was not detected.
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Affiliation(s)
- A Steigen
- Department of Biology, University of Bergen, Bergen, Norway
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10
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Genotyping of Candidatus Syngnamydia salmonis (chlamydiales; Simkaniaceae) co-cultured in Paramoeba perurans (amoebozoa; Paramoebidae). Arch Microbiol 2018; 200:859-867. [PMID: 29455239 PMCID: PMC6019428 DOI: 10.1007/s00203-018-1488-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 12/14/2022]
Abstract
Candidatus Syngnamydia salmonis (Chlamydiales, Simkaniaceae) was described as an epitheliocystis-causing bacterium from the gills of Atlantic salmon (Salmo salar) in Norway. A bacterium showing 99.2% 16S rRNA identity to Cand. S. salmonis is able to multiply in Paramoeba perurans and based on the classification criteria this bacterium could represent the same species as Cand. S. salmonis. Sequencing the genome of the cultured bacterium has made it possible to fulfill the minimal standards for genetic characterization of species within the order Chlamydiales. The complete rRNA genes, the amino acid sequences of SucA, PepF, Adk, HemL, DnaA, FtsK and FabI, are presented in addition to the morphology of the Chlamydia-like morphs in the cytoplasm of P. perurans.
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11
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Bühl H, Eibach D, Nagel M, Greub G, Borel N, Sarpong N, Rettig T, Pesch T, Aeby S, Klöckner A, Brunke M, Krannich S, Kreuels B, Owusu-Dabo E, Hogan B, May J, Henrichfreise B. Chlamydiae in febrile children with respiratory tract symptoms and age-matched controls, Ghana. New Microbes New Infect 2018; 22:44-48. [PMID: 29511568 PMCID: PMC5832669 DOI: 10.1016/j.nmni.2017.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 11/30/2017] [Accepted: 12/21/2017] [Indexed: 11/29/2022] Open
Abstract
Members of the Chlamydiales order are obligate intracellular pathogens causing acute and chronic infectious diseases. Chlamydiaceae are established agents of community- and zoonotically acquired respiratory tract infections, and emerging pathogens among the Chlamydia-related bacteria have been implicated in airway infections. The role of both in airway infections in Africa is underexplored. We performed a case -control study on the prevalence of Chlamydiaceae and Chlamydia-related emerging pathogens in children with febrile respiratory tract infections in West Africa, Ghana. Using a pan-Chlamydiales broad-range real-time PCR, we detected chlamydial DNA in 11 (1.9%) of 572 hospitalized febrile children with respiratory tract symptoms and in 24 (4.3%) of 560 asymptomatic age-matched controls (p 0.03). Chlamydiaceae were found to be common among both symptomatic and healthy Ghanaian children, with Chlamydia pneumoniae being the most prevalent species. Parachlamydiaceae were detected in two children without symptoms but not in the symptomatic group. We identified neither Chlamydia psittaci nor Simkania negevensis but a member of a new chlamydial family that shared 90.2% sequence identity with the 16S rRNA gene of the zoonotic pathogen Chlamydia pecorum. In addition, we found a new Chlamydia-related species that belonged to a novel family sharing 91.3% 16S rRNA sequence identity with Candidatus Syngnamydia venezia. The prevalence and spectrum of chlamydial species differed from previous results obtained from children of other geographic regions and our study indicates that both, Chlamydiaceae and Chlamydia-related bacteria, are not clearly linked to clinical symptoms in Ghanaian children.
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Affiliation(s)
- H Bühl
- Institute for Pharmaceutical Microbiology, University Clinic, University of Bonn, Germany
| | - D Eibach
- Bernhard Nocht Institute for Tropical Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck, Germany
| | - M Nagel
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | - G Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne, Switzerland
| | - N Borel
- Institute of Veterinary Pathology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland
| | - N Sarpong
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck, Germany.,Agogo Presbyterian Hospital, Department of Child Health, Agogo, Ghana
| | - T Rettig
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | - T Pesch
- Institute of Veterinary Pathology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland
| | - S Aeby
- Institute of Microbiology, University Hospital Center and University of Lausanne, Switzerland
| | - A Klöckner
- Institute for Pharmaceutical Microbiology, University Clinic, University of Bonn, Germany.,German Center for Infection Research (DZIF), Bonn, Germany
| | - M Brunke
- Institute for Pharmaceutical Microbiology, University Clinic, University of Bonn, Germany
| | - S Krannich
- Institute for Pharmaceutical Microbiology, University Clinic, University of Bonn, Germany
| | - B Kreuels
- Division of Tropical Medicine, I. Department of Internal Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany
| | - E Owusu-Dabo
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana.,Department of Global Health, School of Public Health, College of Health Sciences, KNUST, Kumasi, Ghana
| | - B Hogan
- Bernhard Nocht Institute for Tropical Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck, Germany
| | - J May
- Bernhard Nocht Institute for Tropical Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck, Germany
| | - B Henrichfreise
- Institute for Pharmaceutical Microbiology, University Clinic, University of Bonn, Germany
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12
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Bayramova F, Jacquier N, Greub G. Insight in the biology of Chlamydia-related bacteria. Microbes Infect 2017; 20:432-440. [PMID: 29269129 DOI: 10.1016/j.micinf.2017.11.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/14/2017] [Accepted: 11/21/2017] [Indexed: 01/21/2023]
Abstract
The Chlamydiales order is composed of obligate intracellular bacteria and includes the Chlamydiaceae family and several family-level lineages called Chlamydia-related bacteria. In this review we will highlight the conserved and distinct biological features between these two groups. We will show how a better characterization of Chlamydia-related bacteria may increase our understanding on the Chlamydiales order evolution, and may help identifying new therapeutic targets to treat chlamydial infections.
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Affiliation(s)
- Firuza Bayramova
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland
| | - Nicolas Jacquier
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland
| | - Gilbert Greub
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland.
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13
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Collingro A, Köstlbacher S, Mussmann M, Stepanauskas R, Hallam SJ, Horn M. Unexpected genomic features in widespread intracellular bacteria: evidence for motility of marine chlamydiae. ISME JOURNAL 2017. [PMID: 28644443 PMCID: PMC5604735 DOI: 10.1038/ismej.2017.95] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chlamydiae are obligate intracellular bacteria comprising important human pathogens and symbionts of protists. Molecular evidence indicates a tremendous diversity of chlamydiae particularly in marine environments, yet our current knowledge is based mainly on terrestrial representatives. Here we provide first insights into the biology of marine chlamydiae representing three divergent clades. Our analysis of single-cell amplified genomes revealed hallmarks of the chlamydial lifestyle, supporting the ancient origin of their characteristic developmental cycle and major virulence mechanisms. Surprisingly, these chlamydial genomes encode a complete flagellar apparatus, a previously unreported feature. We show that flagella are an ancient trait that was subject to differential gene loss among extant chlamydiae. Together with a chemotaxis system, these marine chlamydiae are likely motile, with flagella potentially playing a role during host cell infection. This study broadens our view on chlamydial biology and indicates a largely underestimated potential to adapt to different hosts and environments.
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Affiliation(s)
- Astrid Collingro
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Stephan Köstlbacher
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Marc Mussmann
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | | | - Steven J Hallam
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Genome Science and Technology Program, University of British Columbia, Vancouver, British Columbia, Canada.,Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia, Canada.,Peter Wall Institute for Advanced Studies, University of British Columbia, Vancouver, British Columbia, Canada.,ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthias Horn
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
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14
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Guevara Soto M, Vidondo B, Vaughan L, Rubin JF, Segner H, Samartin S, Schmidt-Posthaus H. Investigations into the temporal development of epitheliocystis infections in brown trout: a histological study. JOURNAL OF FISH DISEASES 2017; 40:811-819. [PMID: 27670837 DOI: 10.1111/jfd.12562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 06/06/2023]
Abstract
Epitheliocystis in Swiss brown trout (Salmo trutta) is a chlamydial infection, mainly caused by Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola. To gain a better understanding of the temporal development of infections in wild brown trout, we investigated epitheliocystis infections during the course of the summer and autumn months of a single year (2015), and compared this to sampling points over the span of the years 2012-2014. The survey focused on tributaries (Venoge and Boiron) of the Rhone flowing in to Lake Geneva. When evaluated histologically, epitheliocystis infections were found throughout the period of investigation with the exception of the month of June. Fifty to 86 animals per sampling were investigated. Highest prevalence and infection intensities were seen in September. A correlation between epitheliocystis infection and water temperatures was not evident. Interyear comparison revealed consistent levels of prevalence and infection intensities in late summer. The absence of infections in June, combined with the consistent interyear results, indicates seasonal fluctuation of epitheliocystis infections in brown trout with a reservoir persisting during winter months from which infections can re-initiate each year. This could either be at levels below detection limits within the brown trout population itself or in an alternative host.
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Affiliation(s)
- M Guevara Soto
- Centre of Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
| | - B Vidondo
- Institute of Veterinary Public Health, University of Bern, Bern, Switzerland
| | - L Vaughan
- Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
| | - J-F Rubin
- Fondation de la Maison de la Rivière, Tolochenaz, Switzerland
| | - H Segner
- Centre of Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
| | - S Samartin
- Institute of Veterinary Public Health, University of Bern, Bern, Switzerland
| | - H Schmidt-Posthaus
- Centre of Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
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15
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Viver T, Orellana LH, Hatt JK, Urdiain M, Díaz S, Richter M, Antón J, Avian M, Amann R, Konstantinidis KT, Rosselló-Móra R. The low diverse gastric microbiome of the jellyfish Cotylorhiza tuberculata is dominated by four novel taxa. Environ Microbiol 2017; 19:3039-3058. [PMID: 28419691 DOI: 10.1111/1462-2920.13763] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/10/2017] [Indexed: 01/06/2023]
Abstract
Cotylorhiza tuberculata is an important scyphozoan jellyfish producing population blooms in the Mediterranean probably due to pelagic ecosystem's decay. Its gastric cavity can serve as a simple model of microbial-animal digestive associations, yet poorly characterized. Using state-of-the-art metagenomic population binning and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH), we show that only four novel clonal phylotypes were consistently associated with multiple jellyfish adults. Two affiliated close to Spiroplasma and Mycoplasma genera, one to chlamydial 'Candidatus Syngnamydia', and one to bacteroidetal Tenacibaculum, and were at least one order of magnitude more abundant than any other bacteria detected. Metabolic modelling predicted an aerobic heterotrophic lifestyle for the chlamydia, which were found intracellularly in Onychodromopsis-like ciliates. The Spiroplasma-like organism was predicted to be an anaerobic fermenter associated to some jellyfish cells, whereas the Tenacibaculum-like as free-living aerobic heterotroph, densely colonizing the mesogleal axis inside the gastric filaments. The association between the jellyfish and its reduced microbiome was close and temporally stable, and possibly related to food digestion and protection from pathogens. Based on the genomic and microscopic data, we propose three candidate taxa: 'Candidatus Syngnamydia medusae', 'Candidatus Medusoplasma mediterranei' and 'Candidatus Tenacibaculum medusae'.
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Affiliation(s)
- Tomeu Viver
- Mediterranean Institute for Advanced Studies (IMEDEA; CSIC-UIB), Marine Microbiology Group, Esporles, E-07190, Spain
| | - Luis H Orellana
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Dr. NW, Atlanta, GA, 30332, USA
| | - Janet K Hatt
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Dr. NW, Atlanta, GA, 30332, USA
| | - Mercedes Urdiain
- Mediterranean Institute for Advanced Studies (IMEDEA; CSIC-UIB), Marine Microbiology Group, Esporles, E-07190, Spain
| | - Sara Díaz
- Mediterranean Institute for Advanced Studies (IMEDEA; CSIC-UIB), Marine Microbiology Group, Esporles, E-07190, Spain
| | | | - Josefa Antón
- Department of Physiology, Genetics and Microbiology, and Multidisciplinary Institute for Environmental Studies Ramon Margalef, University of Alicante, Alicante, Spain
| | - Massimo Avian
- Department of Life Science, University of Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
| | - Rudolf Amann
- Department of Molecular Ecology, Max-Planck-Institut für Marine Mikrobiologie, Bremen, D-28359, Germany
| | - Konstantinos T Konstantinidis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Dr. NW, Atlanta, GA, 30332, USA.,School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr. NW, Atlanta, GA, 30332, USA
| | - Ramon Rosselló-Móra
- Mediterranean Institute for Advanced Studies (IMEDEA; CSIC-UIB), Marine Microbiology Group, Esporles, E-07190, Spain
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16
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Oren A. A plea for linguistic accuracy - also for Candidatus taxa. Int J Syst Evol Microbiol 2017; 67:1085-1094. [PMID: 27926819 DOI: 10.1099/ijsem.0.001715] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
While all names of new taxa submitted to the International Journal of Systematic and Evolutionary Microbiology, either in direct submissions or in validation requests for names effectively published elsewhere, are subject to nomenclatural review to ensure that they are acceptable based on the rules of the International Code of Nomenclature of Prokaryotes, the names of Candidatus taxa have not been subjected to such a review. Formally, this was not necessary because the rank of Candidatus is not covered by the Code, and the names lack the priority afforded validly published names. However, many Candidatus taxa of different ranks are widely discussed in the scientific literature, and a proposal to incorporate the nomenclature of uncultured prokaryotes under the provisions of the Code is currently pending. Therefore, an evaluation of the names of Candidatus taxa published thus far is very timely. Out of the ~400 Candidatus names found in the literature, 120 contradict the current rules of the Code or are otherwise problematic. A list of those names of Candidatus taxa that need correction is presented here and alternative names that agree with the provisions of the Code are proposed.
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Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 91904 Jerusalem, Israel
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17
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Taylor-Brown A, Pillonel T, Bridle A, Qi W, Bachmann NL, Miller TL, Greub G, Nowak B, Seth-Smith HMB, Vaughan L, Polkinghorne A. Culture-independent genomics of a novel chlamydial pathogen of fish provides new insight into host-specific adaptations utilized by these intracellular bacteria. Environ Microbiol 2017; 19:1899-1913. [PMID: 28205377 DOI: 10.1111/1462-2920.13694] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/02/2017] [Accepted: 02/07/2017] [Indexed: 12/12/2022]
Abstract
Several Chlamydiales families are associated with epitheliocystis, a common condition of the fish gill epithelium. These families share common ancestors with the Chlamydiaceae and environmental Chlamydiae. Due to the lack of culture systems, little is known about the biology of these chlamydial fish pathogens. We investigated epitheliocystis in cultured Orange-spotted grouper (Epinephelus coioides) from North Queensland, Australia. Basophilic inclusions were present in the gills of 22/31 fish and the presence of the chlamydial pathogen in the cysts was confirmed by in situ hybridization. Giant grouper (Epinephelus lanceolatus) cultured in the same systems were epitheliocystis free. 16S rRNA gene sequencing revealed a novel member of the Candidatus Parilichlamydiaceae: Ca. Similichlamydia epinephelii. Using metagenomic approaches, we obtained an estimated 68% of the chlamydial genome, revealing that this novel chlamydial pathogen shares a number of key pathogenic hallmarks with the Chlamydiaceae, including an intact Type III Secretion system and several chlamydial virulence factors. This provides additional evidence that these pathogenic mechanisms were acquired early in the evolution of this unique bacterial phylum. The identification and genomic characterization of Ca. S. epinephelii provides new opportunities to study the biology of distantly-related chlamydial pathogens while shining a new light on the evolution of pathogenicity of the Chlamydiaceae.
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Affiliation(s)
- Alyce Taylor-Brown
- Centre for Animal Health Innovation, Faculty of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland, 4556, Australia
| | - Trestan Pillonel
- Institute of Microbiology, University of Lausanne, Lausanne, CH-1011, Switzerland
| | - Andrew Bridle
- Institute of Marine and Antarctic Studies, University of Tasmania, Newnham, Tasmania, 7248, Australia
| | - Weihong Qi
- Functional Genomics Centre, University of Zurich, Zurich, CH-8057, Switzerland
| | - Nathan L Bachmann
- Centre for Animal Health Innovation, Faculty of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland, 4556, Australia
| | - Terrence L Miller
- Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Cairns, Queensland, 4878, Australia
| | - Gilbert Greub
- Institute of Microbiology, University of Lausanne, Lausanne, CH-1011, Switzerland
| | - Barbara Nowak
- Institute of Marine and Antarctic Studies, University of Tasmania, Newnham, Tasmania, 7248, Australia
| | - Helena M B Seth-Smith
- Functional Genomics Centre, University of Zurich, Zurich, CH-8057, Switzerland.,Institute of Veterinary Pathology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Lloyd Vaughan
- Institute of Veterinary Pathology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, Faculty of Science, Engineering and Education, University of the Sunshine Coast, Sippy Downs, Queensland, 4556, Australia
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18
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The value of cultures to modern microbiology. Antonie van Leeuwenhoek 2017; 110:1247-1256. [DOI: 10.1007/s10482-017-0840-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 01/31/2017] [Indexed: 02/02/2023]
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19
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Burnard D, Weaver H, Gillett A, Loader J, Flanagan C, Polkinghorne A. Novel Chlamydiales genotypes identified in ticks from Australian wildlife. Parasit Vectors 2017; 10:46. [PMID: 28122598 PMCID: PMC5267465 DOI: 10.1186/s13071-017-1994-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/19/2017] [Indexed: 11/24/2022] Open
Abstract
Background Members of the order Chlamydiales are known for their potential as human and veterinary bacterial pathogens. Despite this recognition, epidemiological factors such as routes of transmission are yet to be fully defined. Ticks are well known vectors for many other infections with several reports recently describing the presence of bacteria in the order Chlamydiales in these arthropods. Australian wildlife are hosts to an extensive range of tick species. Evidence is also growing that the marsupial hosts these ticks parasitise can also be infected by a number of bacteria in the order Chlamydiales, with at least one species, Chlamydia pecorum, posing a significant conservation threat. In the current study, we investigated the presence and identity of Chlamydiales in 438 ixodid ticks parasitizing wildlife in Australia by screening with a pan-Chlamydiales specific targeting the 16S rRNA gene. Results Pan-Chlamydiales specific PCR assays confirmed the common presence of Chlamydiales in Australian ticks parasitising a range of native wildlife. Interestingly, we did not detect any Chlamydiaceae, including C. pecorum, the ubiquitous pathogen of the koala. Instead, the Chlamydiales diversity that could be resolved indicated that Australian ticks carry at least six novel Chlamydiales genotypes. Phylogenetic analysis of the 16S rRNA sequences (663 bp) of these novel Chlamydiales suggests that three of these genotypes are associated with the Simkaniaceae and putatively belong to three distinct novel strains of Fritschea spp. and three genotypes are related to the “Ca. Rhabdochlamydiaceae” and putatively belong to a novel genus, Rhabdochlamydia species and strain, respectively. Conclusions Sequence results suggest Australian wildlife ticks harbour a range of unique Chlamydiales bacteria that belong to families previously identified in a range of arthropod species. The results of this work also suggest that it is unlikely that arthropods act as vectors of pathogenic members of the family Chlamydiaceae, including C. pecorum, in Australian wildlife. The biology of novel Chlamydiales identified in arthropods remain unknown. The pathogenic role of the novel Chlamydiales identified in this study and the role that ticks may play in their transmission needs to be explored further. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-1994-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Delaney Burnard
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4556, Australia
| | - Haylee Weaver
- Australian Government, Department of Environment and Energy, Australian Biological Resources Study, GPO Box 787, Canberra, ACT, 2601, Australia
| | - Amber Gillett
- Australia Zoo Wildlife Hospital, Steve Irwin Way, Beerwah, QLD, 4519, Australia
| | - Joanne Loader
- Endeavour Veterinary Ecology Pty Ltd, 1695 Pumicestone Rd, Toorbul, QLD, 4510, Australia
| | - Cheyne Flanagan
- Port Macquarie Koala Hospital, Roto House Historic Site, Cnr Lord Street and Roto Place, Port Macquarie, 2444, NSW, Australia
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4556, Australia.
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20
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Fehr AGJ, Ruetten M, Seth-Smith HMB, Nufer L, Voegtlin A, Lehner A, Greub G, Crosier PS, Neuhauss SCF, Vaughan L. A Zebrafish Model for Chlamydia Infection with the Obligate Intracellular Pathogen Waddlia chondrophila. Front Microbiol 2016; 7:1829. [PMID: 27917158 PMCID: PMC5114312 DOI: 10.3389/fmicb.2016.01829] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/01/2016] [Indexed: 01/22/2023] Open
Abstract
Obligate intracellular chlamydial bacteria of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) superphylum are important pathogens of terrestrial and marine vertebrates, yet many features of their pathogenesis and host specificity are still unknown. This is particularly true for families such as the Waddliacea which, in addition to epithelia, cellular targets for nearly all Chlamydia, can infect and replicate in macrophages, an important arm of the innate immune system or in their free-living amoebal counterparts. An ideal pathogen model system should include both host and pathogen, which led us to develop the first larval zebrafish model for chlamydial infections with Waddlia chondrophila. By varying the means and sites of application, epithelial cells of the swim bladder, endothelial cells of the vasculature and phagocytosing cells of the innate immune system became preferred targets for infection in zebrafish larvae. Through the use of transgenic zebrafish, we could observe recruitment of neutrophils to the infection site and demonstrate for the first time that W. chondrophila is taken up and replicates in these phagocytic cells and not only in macrophages. Furthermore, we present evidence that myeloid differentiation factor 88 (MyD88) mediated signaling plays a role in the innate immune reaction to W. chondrophila, eventually by Toll-like receptor (TLRs) recognition. Infected larvae with depleted levels of MyD88 showed a higher infection load and a lower survival rate compared to control fish. This work presents a new and potentially powerful non-mammalian experimental model to study the pathology of chlamydial virulence in vivo and opens up new possibilities for investigation of other members of the PVC superphylum.
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Affiliation(s)
- Alexander G J Fehr
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Maja Ruetten
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Helena M B Seth-Smith
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of ZurichZurich, Switzerland; Functional Genomics Center Zurich, Molecular and Life Sciences, University of ZurichZurich, Switzerland
| | - Lisbeth Nufer
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Andrea Voegtlin
- Vetsuisse Faculty, Institute of Veterinary Bacteriology, University of Zurich Zurich, Switzerland
| | - Angelika Lehner
- Vetsuisse Faculty, Institute for Food Safety and Hygiene, University of Zurich Zurich, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne Lausanne, Switzerland
| | - Philip S Crosier
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland Auckland, New Zealand
| | | | - Lloyd Vaughan
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich Zurich, Switzerland
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21
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Vouga M, Baud D, Greub G. Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order. Crit Rev Microbiol 2016; 43:62-80. [PMID: 27786615 DOI: 10.3109/1040841x.2016.1165650] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Simkania negevensis is a Chlamydia-related bacterium discovered in 1993 and represents the founding member of the Simkaniaceae family within the Chlamydiales order. As other Chlamydiales, it is an obligate intracellular bacterium characterized by a biphasic developmental cycle. Its similarities with the pathogenic Chlamydia trachomatis and Chlamydia pneumoniae make it an interesting bacterium. So far, little is known about its biology, but S. negevensis harbors various microbiological characteristics of interest, including a strong association of the Simkania-containing vacuole with the ER and the presence of an intron in the 23S rRNA encoding gene. Evidence of human exposition has been reported worldwide. However, there is a lack of robust clinical studies evaluating its implication in human diseases; current data suggest an association with pneumonia and bronchiolitis making S. negevensis a potential emerging pathogen. Owing to its fastidious growth requirements, the clinical relevance of S. negevensis is probably underestimated. In this review, we summarize the current knowledge on S. negevensis and explore future research challenges.
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Affiliation(s)
- Manon Vouga
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,b Department "Femme-Mère-Enfant" , Materno-Fetal and Obstetrics Research Unit, University Hospital , Lausanne , Switzerland
| | - David Baud
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,b Department "Femme-Mère-Enfant" , Materno-Fetal and Obstetrics Research Unit, University Hospital , Lausanne , Switzerland
| | - Gilbert Greub
- a Institute of Microbiology , Center for Research on Intracellular Bacteria, Faculty of Biology and Medicine, University and University Hospital of Lausanne , Lausanne , Switzerland.,c Infectious Diseases Unit , University hospital , Lausanne , Switzerland
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22
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Qi W, Vaughan L, Katharios P, Schlapbach R, Seth-Smith HMB. Host-Associated Genomic Features of the Novel Uncultured Intracellular Pathogen Ca. Ichthyocystis Revealed by Direct Sequencing of Epitheliocysts. Genome Biol Evol 2016; 8:1672-89. [PMID: 27190004 PMCID: PMC4943182 DOI: 10.1093/gbe/evw111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2016] [Indexed: 12/24/2022] Open
Abstract
Advances in single-cell and mini-metagenome sequencing have enabled important investigations into uncultured bacteria. In this study, we applied the mini-metagenome sequencing method to assemble genome drafts of the uncultured causative agents of epitheliocystis, an emerging infectious disease in the Mediterranean aquaculture species gilthead seabream. We sequenced multiple cyst samples and constructed 11 genome drafts from a novel beta-proteobacterial lineage, Candidatus Ichthyocystis. The draft genomes demonstrate features typical of pathogenic bacteria with an obligate intracellular lifestyle: a reduced genome of up to 2.6 Mb, reduced G + C content, and reduced metabolic capacity. Reconstruction of metabolic pathways reveals that Ca Ichthyocystis genomes lack all amino acid synthesis pathways, compelling them to scavenge from the fish host. All genomes encode type II, III, and IV secretion systems, a large repertoire of predicted effectors, and a type IV pilus. These are all considered to be virulence factors, required for adherence, invasion, and host manipulation. However, no evidence of lipopolysaccharide synthesis could be found. Beyond the core functions shared within the genus, alignments showed distinction into different species, characterized by alternative large gene families. These comprise up to a third of each genome, appear to have arisen through duplication and diversification, encode many effector proteins, and are seemingly critical for virulence. Thus, Ca Ichthyocystis represents a novel obligatory intracellular pathogenic beta-proteobacterial lineage. The methods used: mini-metagenome analysis and manual annotation, have generated important insights into the lifestyle and evolution of the novel, uncultured pathogens, elucidating many putative virulence factors including an unprecedented array of novel gene families.
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Affiliation(s)
- Weihong Qi
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Lloyd Vaughan
- Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
| | - Pantelis Katharios
- Hellenic Center for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture, Heraklion, Greece
| | - Ralph Schlapbach
- Functional Genomics Center Zurich, University of Zurich, Switzerland
| | - Helena M B Seth-Smith
- Functional Genomics Center Zurich, University of Zurich, Switzerland Vetsuisse Faculty, Institute for Veterinary Pathology, University of Zurich, Switzerland
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23
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Emerging pathogens of gilthead seabream: characterisation and genomic analysis of novel intracellular β-proteobacteria. ISME JOURNAL 2016; 10:1791-803. [PMID: 26849311 DOI: 10.1038/ismej.2015.223] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 10/11/2015] [Accepted: 10/26/2015] [Indexed: 12/16/2022]
Abstract
New and emerging environmental pathogens pose some of the greatest threats to modern aquaculture, a critical source of food protein globally. As with other intensive farming practices, increasing our understanding of the biology of infections is important to improve animal welfare and husbandry. The gill infection epitheliocystis is increasingly problematic in gilthead seabream (Sparus aurata), a major Mediterranean aquaculture species. Epitheliocystis is generally associated with chlamydial bacteria, yet we were not able to localise chlamydial targets within the major gilthead seabream lesions. Two previously unidentified species within a novel β-proteobacterial genus were instead identified. These co-infecting intracellular bacteria have been characterised using high-resolution imaging and genomics, presenting the most comprehensive study on epitheliocystis agents to date. Draft genomes of the two uncultured species, Ca. Ichthyocystis hellenicum and Ca. Ichthyocystis sparus, have been de novo sequenced and annotated from preserved material. Analysis of the genomes shows a compact core indicating a metabolic dependency on the host, and an accessory genome with an unprecedented number of tandemly arrayed gene families. This study represents a critical insight into novel, emerging fish pathogens and will be used to underpin future investigations into the bacterial origins, and to develop diagnostic and treatment strategies.
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The emergence of epitheliocystis in the upper Rhone region: evidence for Chlamydiae in wild and farmed salmonid populations. Arch Microbiol 2016; 198:315-24. [PMID: 26802008 DOI: 10.1007/s00203-016-1192-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/17/2015] [Accepted: 01/12/2016] [Indexed: 10/22/2022]
Abstract
We present the first study comparing epitheliocystis in a wild and farmed salmonid in Europe. Sampling three tributaries to the Lake Geneva, including one from headwaters to river mouth, revealed an unequal distribution of epitheliocystis in brown trout (Salmo trutta). When evaluated histologically and comparing sites grouped as wild versus farm, the probability of finding infected trout is higher on farms. In contrast, the infection intensities, as estimated by the number of cysts per gill arch, were higher on average and showed maximum values in the wild trout. Sequence analysis showed the most common epitheliocystis agents were Candidatus Piscichlamydia salmonis, all clustering into a single clade, whereas Candidatus Clavichlamydia salmonicola sequences cluster in two closely related subspecies, of which one was mostly found in farmed fish and the other exclusively in wild brown trout, indicating that farms are unlikely to be the source of infections in wild trout. A detailed morphological analysis of cysts using transmission electron microscopy revealed unique features illustrating the wide divergence existing between Ca. P. salmonis and Ca. C. salmonicola within the phylum Chlamydiae.
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Environmental marine pathogen isolation using mesocosm culture of sharpsnout seabream: striking genomic and morphological features of novel Endozoicomonas sp. Sci Rep 2015; 5:17609. [PMID: 26639610 PMCID: PMC4671022 DOI: 10.1038/srep17609] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/02/2015] [Indexed: 11/09/2022] Open
Abstract
Aquaculture is a burgeoning industry, requiring diversification into new farmed species, which are often at risk from infectious disease. We used a mesocosm technique to investigate the susceptibility of sharpsnout seabream (Diplodus puntazzo) larvae to potential environmental pathogens in seawater compared to control borehole water. Fish exposed to seawater succumbed to epitheliocystis from 21 days post hatching, causing mortality in a quarter of the hosts. The pathogen responsible was not chlamydial, as is often found in epitheliocystis, but a novel species of the γ-proteobacterial genus Endozoicomonas. Detailed characterisation of this pathogen within the infectious lesions using high resolution fluorescent and electron microscopy showed densely packed rod shaped bacteria. A draft genome sequence of this uncultured bacterium was obtained from preserved material. Comparison with the genome of the Endozoicomonas elysicola type strain shows that the genome of Ca. Endozoicomonas cretensis is undergoing decay through loss of functional genes and insertion sequence expansion, often indicative of adaptation to a new niche or restriction to an alternative lifestyle. These results demonstrate the advantage of mesocosm studies for investigating the effect of environmental bacteria on susceptible hosts and provide an important insight into the genome dynamics of a novel fish pathogen.
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Characteristics of chlamydia-like organisms pathogenic to fish. J Appl Genet 2015; 57:135-41. [PMID: 26160214 PMCID: PMC4731428 DOI: 10.1007/s13353-015-0303-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/11/2015] [Accepted: 06/22/2015] [Indexed: 01/08/2023]
Abstract
Bacteria from the Chlamydiales order have been long known, especially as pathogenic bacteria to humans and many animal species, principally including birds and mammals. But for slightly over 20 years, they have been identified in the aquatic environment as endosymbionts of amoebas and sea worms. For several years, they have also been recorded as a cause of diseases among fish, causing respiratory system infections in the form of epitheliocystis of the gill. At present, 11 chlamydia-like organisms pathogenic to fish have been described, including nine new ones, classified into six families, four of which are already known (Parachlamydiaceae, Rhabdochlamydiaceae, Candidatus Parilichlamydiaceae, Candidatus Clavichlamydiaceae) and two newly created families, namely Candidatus Actinochlamydiaceae and Candidatus Parilichlamydiaceae. This paper characterises 11 chlamydia-like organisms, as well as seven isolates not classified into families, which are pathogenic to fish, presenting their genetical properties allowing for their classification, as well as morphological properties and diseases caused.
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Taylor-Brown A, Vaughan L, Greub G, Timms P, Polkinghorne A. Twenty years of research into Chlamydia-like organisms: a revolution in our understanding of the biology and pathogenicity of members of the phylum Chlamydiae. Pathog Dis 2014; 73:1-15. [PMID: 25854000 DOI: 10.1093/femspd/ftu009] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2014] [Indexed: 11/13/2022] Open
Abstract
Chlamydiae are obligate intracellular bacteria that share a unique but remarkably conserved biphasic developmental cycle that relies on a eukaryotic host cell for survival. Although the phylum was originally thought to only contain one family, the Chlamydiaceae, a total of nine families are now recognized. These so-called Chlamydia-like organisms (CLOs) are also referred to as 'environmental chlamydiae', as many were initially isolated from environmental sources. However, these organisms are also emerging pathogens, as many, such as Parachlamydia sp., Simkania sp. and Waddlia sp., have been associated with human disease, and others, such as Piscichlamydia sp. and Parilichlamydia sp., have been documented in association with diseases in animals. Their strict intracellular nature and the requirement for cell culture have been a confounding factor in characterizing the biology and pathogenicity of CLOs. Nevertheless, the genomes of seven CLO species have now been sequenced, providing new information on their potential ability to adapt to a wide range of hosts. As new isolation and diagnostic methods advance, we are able to further explore the richness of this phylum with further research likely to help define the true pathogenic potential of the CLOs while also providing insight into the origins of the 'traditional' chlamydiae.
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Affiliation(s)
- Alyce Taylor-Brown
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Lloyd Vaughan
- Institute of Veterinary Pathology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Adam Polkinghorne
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
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Steigen A, Karlsbakk E, Plarre H, Watanabe K, Øvergård AC, Brevik Ø, Nylund A. A new intracellular bacterium, Candidatus Similichlamydia labri sp. nov. (Chlamydiaceae) producing epitheliocysts in ballan wrasse, Labrus bergylta (Pisces, Labridae). Arch Microbiol 2014; 197:311-8. [PMID: 25416125 PMCID: PMC4326665 DOI: 10.1007/s00203-014-1061-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 11/11/2014] [Indexed: 11/25/2022]
Abstract
Certain wrasse species (Labridae) are used as cleaner fish in salmon farms on the Norwegian coast, reducing salmon louse intensities. The pathogen repertoire of wrasse in Norway is poorly known, and the objective of the present study is to describe a novel intracellular bacterium detected in Norwegian Labrus bergylta. Histological examination of gill tissues from ballan wrasse, L. bergylta, revealed epitheliocysts occurring basally to the secondary lamellae in the interlamellar epithelium. Ultrastructurally, these had bacteria-filled inclusions with thickened membranes and radiating ray-like structures (actinae). 16S rRNA gene sequences from the gill bacteria showed the highest (97.1 %) similarity to Candidatus Similichlamydia latridicola from the gills of the latrid marine fish Latris lineata in Australia and 94.9 % similarity to Candidatus Actinochlamydia clariae, causing epitheliocystis in the freshwater catfish Clarias gariepinus in Uganda. A total of 47 gill samples from L. bergylta from Western Norway were screened by real time RT-PCR with an assay targeting Candidatus Actinochlamydiaceae 16S rRNA. Prevalence was 100 %. We propose the name Candidatus Similichlamydia labri sp. nov. for this new agent producing gill epitheliocysts in L. bergylta.
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Affiliation(s)
- Andreas Steigen
- Department of Biology, University of Bergen, Bergen, Norway,
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Nylund S, Steigen A, Karlsbakk E, Plarre H, Andersen L, Karlsen M, Watanabe K, Nylund A. Characterization of 'Candidatus Syngnamydia salmonis' (Chlamydiales, Simkaniaceae), a bacterium associated with epitheliocystis in Atlantic salmon (Salmo salar L.). Arch Microbiol 2014; 197:17-25. [PMID: 25294188 PMCID: PMC4282687 DOI: 10.1007/s00203-014-1038-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 09/12/2014] [Accepted: 09/13/2014] [Indexed: 10/29/2022]
Abstract
Two Chlamydiales have previously been found to infect Atlantic salmon (Salmo salar L.), Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola. Both develop intracellularly in cyst-like inclusions in gill cells, generally referred to as epitheliocysts. Here, we present evidence for the association of a novel species of Chlamydiales with epitheliocystis in Atlantic salmon. Based on its partial 16S rRNA gene sequence, it is a new member of the family Simkaniaceae, and a 95.7 % identity to the type species Candidatus Syngnamydia venezia suggests inclusion in the candidate genus Syngnamydia. The presence of the bacterium in epitheliocysts in gills of Atlantic salmon was demonstrated by RNA-RNA hybridization. Ultrastructurally, the novel bacterium produces pleomorphic reticulate bodies and elementary bodies (EBs) with a characteristic morphology. The EBs are short rods with a terminal disc-like cap area, a sub-apical spherical vacuole-like electron-lucent structure and a post-equatorial nucleoid. We propose the name Candidatus Syngnamydia salmonis for this new agent from epitheliocysts in seawater-reared salmon .
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Affiliation(s)
- Stian Nylund
- Department of Biology, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
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Kebbi-Beghdadi C, Greub G. Importance of amoebae as a tool to isolate amoeba-resisting microorganisms and for their ecology and evolution: the Chlamydia paradigm. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:309-24. [PMID: 24992529 DOI: 10.1111/1758-2229.12155] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 02/14/2014] [Accepted: 02/16/2014] [Indexed: 05/23/2023]
Abstract
Free-living amoebae are distributed worldwide and are frequently in contact with humans and animals. As cysts, they can survive in very harsh conditions and resist biocides and most disinfection procedures. Several microorganisms, called amoeba-resisting microorganisms (ARMs), have evolved to survive and multiply within these protozoa. Among them are many important pathogens, such as Legionella and Mycobacteria, and also several newly discovered Chlamydia-related bacteria, such as Parachlamydia acanthamoebae, Estrella lausannensis, Simkania negevensis or Waddlia chondrophila whose pathogenic role towards human or animal is strongly suspected. Amoebae represent an evolutionary crib for their resistant microorganisms since they can exchange genetic material with other ARMs and develop virulence traits that will be further used to infect other professional phagocytes. Moreover, amoebae constitute an ideal tool to isolate strict intracellular microorganisms from complex microbiota, since they will feed on other fast-growing bacteria, such as coliforms potentially present in the investigated samples. The paradigm that ARMs are likely resistant to macrophages, another phagocytic cell, and that they are likely virulent towards humans and animals is only partially true. Indeed, we provide examples of the Chlamydiales order that challenge this assumption and suggest that the ability to multiply in protozoa does not strictly correlate with pathogenicity and that we should rather use the ability to replicate in multiple and diverse eukaryotic cells as an indirect marker of virulence towards mammals. Thus, cell-culture-based microbial culturomics should be used in the future to try to discover new pathogenic bacterial species.
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Affiliation(s)
- Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center, University of Lausanne, Lausanne, Switzerland
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