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Dang M, Dien TD, Ha VT, Hua VC, Thanh NTH, Nowak BF. Epitheliocystis in armoured catfish (Pterygoplichthys spp.), anabas (Anabas testudineus) and tilapia (Oreochromis niloticus) in central Vietnam. JOURNAL OF FISH DISEASES 2022; 45:755-760. [PMID: 35180313 DOI: 10.1111/jfd.13598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/08/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Mai Dang
- Institute for Veterinary Research and Development of Central Vietnam, Nha Trang, Vietnam
| | - Tran Duc Dien
- Coastal Branch, Vietnam - Russia Tropical Center, Nha Trang, Vietnam
| | - Vo Thi Ha
- Coastal Branch, Vietnam - Russia Tropical Center, Nha Trang, Vietnam
| | - Viet Cuong Hua
- Institute for Veterinary Research and Development of Central Vietnam, Nha Trang, Vietnam
| | | | - Barbara F Nowak
- Institute for Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia
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Expansion of the Beta-Proteobacterial Genus Ca. Ichthyocystis: A Case Report of Epitheliocystis in the Pompano Trachinotus ovatus. Pathogens 2022; 11:pathogens11040421. [PMID: 35456096 PMCID: PMC9025894 DOI: 10.3390/pathogens11040421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 12/10/2022] Open
Abstract
Epitheliocystis is a disease caused by a wide variety of host-specific intracellular bacteria infecting fish gills. In the Mediterranean Sea, epitheliocystis has been recently associated with a novel genus of beta-proteobacteria, the Ca. Ichthyocystis genus. In the present study, we report a case of epitheliocystis in a wild-caught specimen of pompano Trachinotus ovatus in Crete, Greece. Molecular analysis of partial 16s rRNA sequence led to the discovery of a putative novel species of the Ca. Ichthyocystis genus. Investigation of the phylogenetic relationship between closely related sequences deposited in NCBI suggests that bacterial ancestors in gilthead seabream might have a pivotal role in the differentiation of genus.
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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:microorganisms10030627. [PMID: 35336202 PMCID: PMC8949381 DOI: 10.3390/microorganisms10030627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [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.)
- Correspondence:
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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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Sood N, Pradhan PK, Verma DK, Yadav MK, Dev AK, Swaminathan TR, Sood NK. Candidatus Actinochlamydia pangasiae sp. nov. (Chlamydiales, Actinochlamydiaceae), a bacterium associated with epitheliocystis in Pangasianodon hypophthalmus. JOURNAL OF FISH DISEASES 2018; 41:281-290. [PMID: 28940578 DOI: 10.1111/jfd.12711] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/01/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
Chlamydial infections are recognised as causative agent of epitheliocystis, reported from over 90 fish species. In the present study, the farmed striped catfish Pangasianodon hypophthalmus (14-15 cm, 70-90 g) with a history of cumulative mortality of about 23% during June and July 2015, were brought to the laboratory. The histopathological examination of gills from the affected fish revealed presence of granular basophilic intracellular inclusions, mostly at the base of the interlamellar region and in gill filaments. A concurrent infection with Trichodina spp., Ichthyobodo spp. and Dactylogyrus spp. was observed in the gills. The presence of chlamydial DNA in the gills of affected fish was confirmed by amplification and sequencing of 16S rRNA gene. BLAST-n analysis of these amplicons revealed maximum similarity (96%) with Candidatus Actinochlamydia clariae. On the basis of phylogenetic analysis, it was inferred that the epitheliocystis agents from striped catfish were novel and belonged to the taxon Ca. Actinochlamydia. It is proposed that epitheliocystis agents from striped catfish will be named as Ca. Actinochlamydia pangasiae. The 16S rRNA gene amplicons from novel chlamydiae were labelled and linked to inclusions by in situ hybridisation. This is the first report of epitheliocystis from India in a new fish host P. hypophthalmus.
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Affiliation(s)
- N Sood
- ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh, India
| | - P K Pradhan
- ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh, India
| | - D K Verma
- ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh, India
| | - M K Yadav
- ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh, India
| | - A K Dev
- ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh, India
| | - T R Swaminathan
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-NBFGR, Kochi, Kerala
| | - N K Sood
- Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
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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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Guevara Soto M, Vaughan L, Segner H, Wahli T, Vidondo B, Schmidt-Posthaus H. Epitheliocystis Distribution and Characterization in Brown Trout (Salmo trutta) from the Headwaters of Two Major European Rivers, the Rhine and Rhone. Front Physiol 2016; 7:131. [PMID: 27148070 PMCID: PMC4834352 DOI: 10.3389/fphys.2016.00131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/24/2016] [Indexed: 11/13/2022] Open
Abstract
We present a first description of the distribution and characterization of epitheliocystis infections in brown trout (Salmo trutta) from the upper catchments of two major European rivers, the Rhine and the Rhone. Overall, epitheliocystis was widely distributed, with 70% of the Rhine and 67% of the Rhone sites harboring epitheliocystis positive brown trout. The epitheliocystis agents Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola could be identified in both catchments, although their relative proportions differed from site to site. Additionally, in two rivers in the Rhine catchment, a new species of Candidatus Similichlamydia was identified. Based on the histology, infection intensity, and severity of pathological changes were significantly more pronounced in mixed chlamydial infections, whereas single infections showed only low numbers of cysts and mild pathology. Infections could be found over a wide range of temperatures, which showed no correlation to infection prevalence or intensity.
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Affiliation(s)
- Maricruz Guevara Soto
- Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, University of Bern Bern, Switzerland
| | - Lloyd Vaughan
- Department of Pathobiology, Institute of Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Helmut Segner
- Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, University of Bern Bern, Switzerland
| | - Thomas Wahli
- Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, University of Bern Bern, Switzerland
| | - Beatriz Vidondo
- Department of Clinical Research and Veterinary Public Health, Veterinary Public Health Institute, University of Bern Bern, Switzerland
| | - Heike Schmidt-Posthaus
- Department of Infectious Diseases and Pathobiology, Centre of Fish and Wildlife Health, University of Bern Bern, Switzerland
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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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Katharios P, Kokkari C, Dourala N, Smyrli M. First report of Edwardsiellosis in cage-cultured sharpsnout sea bream, Diplodus puntazzo from the Mediterranean. BMC Vet Res 2015; 11:155. [PMID: 26193880 PMCID: PMC4508803 DOI: 10.1186/s12917-015-0482-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/14/2015] [Indexed: 02/04/2023] Open
Abstract
Background Edwardsiella tarda, is a serious bacterial pathogen affecting a broad range of aquaculture fish species. The bacterium has also been reported as a human pathogen, however recent studies have dissociated the fish pathogenic Edwardsiella from those isolated from humans by placing them in a new species, E. piscicida. Here we report the first case of Edwardsiellosis in cultured sharpsnout sea breams, Diplodus puntazzo in Greece. Case presentation The disease has affected cultured sharpsnout sea breams of a commercial fish farm in a single location in East Greece. Two populations of sharpsnout sea breams stocked in two consecutive years in floating cages presented signs of disease which included nodules and abscesses in spleen and kidney, morbidity and cumulative mortality reaching 5.3 %. Using microbiological, biochemical and molecular tools we have identified Edwardsiella sp. as the main aetiological factor of the disease. Following phylogenetic analysis the bacterial isolates are grouped with the newly described Edwardsiella piscicida species. Conclusions This is the first report of Edwardsiellosis in this species but most importantly in sea cage-cultured fish in the Mediterranean which may pose a serious threat for aquaculture fish species in this region.
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Affiliation(s)
- Pantelis Katharios
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Former American Base of Gournes, Heraklion, 71003, Crete, Greece.
| | - Constantina Kokkari
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Former American Base of Gournes, Heraklion, 71003, Crete, Greece.
| | - Nancy Dourala
- Selonda Aquaculture, Navarhou Nikodimou 30, 105 56, Athens, Greece.
| | - Maria Smyrli
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Former American Base of Gournes, Heraklion, 71003, Crete, Greece.
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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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11
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Stride MC, Polkinghome A, Nowak BF. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species. Vet Microbiol 2014; 171:258-66. [PMID: 24932463 DOI: 10.1016/j.vetmic.2014.03.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.
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12
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Stride M, Polkinghorne A, Nowak B. Chlamydial infections of fish: Diverse pathogens and emerging causes of disease in aquaculture species. Vet Microbiol 2014; 170:19-27. [DOI: 10.1016/j.vetmic.2014.01.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
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13
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Mendoza M, Güiza L, Martinez X, Caraballo X, Rojas J, Aranguren LF, Salazar M. A novel agent (Endozoicomonas elysicola) responsible for epitheliocystis in cobia Rachycentrum canadum larvae. DISEASES OF AQUATIC ORGANISMS 2013; 106:31-37. [PMID: 24062550 DOI: 10.3354/dao02636] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Aquaculture of cobia has gained popularity in the last decade, and this species is now farmed in several countries in Latin America and Asia. Despite recent improvement in production techniques that allowed the expansion of the industry, little is known about the diseases that affect cobia during the larviculture stage. In this article we investigated the cause of mass mortalities occurring 13-20 d post-hatching in 3 cycles of cobia larviculture. Wet mounts from diseased larvae gills revealed the presence of cyst-like basophilic inclusions. DNA from the cysts was extracted and PCR amplified using the 16S rRNA gene universal primers for prokaryotes. The amplified products were sequenced and analyzed using BLAST, finding a similarity of 99% with Endozoicomonas elysicola, a Gram-negative bacterium. Confirmation of E. elysicola was conducted by designing a specific probe for in situ hybridization. Specific primers were also designed for diagnostic purposes. This is the first report of epitheliocystis in cobia larvae and also the first report of E. elysicola as an epitheliocystis-causing agent.
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Affiliation(s)
- Mabel Mendoza
- Corporación Centro de Investigación de la acuicultura en Colombia-CENIACUA, Carrera 9B 113-60 Bogotá, 110111, Colombia
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Molecular characterization of "Candidatus Similichlamydia latridicola" gen. nov., sp. nov. (Chlamydiales: "Candidatus Parilichlamydiaceae"), a novel Chlamydia-like epitheliocystis agent in the striped trumpeter, Latris lineata (Forster). Appl Environ Microbiol 2013; 79:4914-20. [PMID: 23770893 DOI: 10.1128/aem.00746-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Histological analysis of gill samples taken from individuals of Latris lineata reared in aquaculture in Tasmania, Australia, and those sampled from the wild revealed the presence of epitheliocystis-like basophilic inclusions. Subsequent morphological, in situ hybridization, and molecular analyses were performed to confirm the presence of this disease and discovered a Chlamydia-like organism associated with this condition, and the criteria set by Fredericks and Relman's postulates were used to establish disease causation. Three distinct 16S rRNA genotypes were sequenced from 16 fish, and phylogenetic analyses of the nearly full-length 16S rRNA sequences generated for this bacterial agent indicated that they were nearly identical novel members of the order Chlamydiales. This new taxon formed a well-supported clade with "Candidatus Parilichlamydia carangidicola" from the yellowtail kingfish (Seriola lalandi). On the basis of sequence divergence over the 16S rRNA region relative to all other members of the order Chlamydiales, a new genus and species are proposed here for the Chlamydia-like bacterium from L. lineata, i.e., "Candidatus Similichlamydia latridicola" gen. nov., sp. nov.
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Stride MC, Polkinghorne A, Miller TL, Groff JM, Lapatra SE, Nowak BF. Molecular characterization of "Candidatus Parilichlamydia carangidicola," a novel Chlamydia-like epitheliocystis agent in yellowtail kingfish, Seriola lalandi (Valenciennes), and the proposal of a new family, "Candidatus Parilichlamydiaceae" fam. nov. (order Chlamydiales). Appl Environ Microbiol 2013; 79:1590-7. [PMID: 23275507 PMCID: PMC3591964 DOI: 10.1128/aem.02899-12] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 12/19/2012] [Indexed: 11/20/2022] Open
Abstract
Three cohorts of farmed yellowtail kingfish (Seriola lalandi) from South Australia were examined for Chlamydia-like organisms associated with epitheliocystis. To characterize the bacteria, 38 gill samples were processed for histopathology, electron microscopy, and 16S rRNA amplification, sequencing, and phylogenetic analysis. Microscopically, the presence of membrane-enclosed cysts was observed within the gill lamellae. Also observed was hyperplasia of the epithelial cells with cytoplasmic vacuolization and fusion of the gill lamellae. Transmission electron microscopy revealed morphological features of the reticulate and intermediate bodies typical of members of the order Chlamydiales. A novel 1,393-bp 16S chlamydial rRNA sequence was amplified from gill DNA extracted from fish in all cohorts over a 3-year period that corresponded to the 16S rRNA sequence amplified directly from laser-dissected cysts. This sequence was only 87% similar to the reported "Candidatus Piscichlamydia salmonis" (AY462244) from Atlantic salmon and Arctic charr. Phylogenetic analysis of this sequence against 35 Chlamydia and Chlamydia-like bacteria revealed that this novel bacterium belongs to an undescribed family lineage in the order Chlamydiales. Based on these observations, we propose this bacterium of yellowtail kingfish be known as "Candidatus Parilichlamydia carangidicola" and that the new family be known as "Candidatus Parilichlamydiaceae."
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Affiliation(s)
- M C Stride
- University of Tasmania, Launceston, Tasmania, Australia.
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Schmidt-Posthaus H, Polkinghorne A, Nufer L, Schifferli A, Zimmermann DR, Segner H, Steiner P, Vaughan L. A natural freshwater origin for two chlamydial species, Candidatus Piscichlamydia salmonis and Candidatus Clavochlamydia salmonicola, causing mixed infections in wild brown trout (Salmo trutta). Environ Microbiol 2011; 14:2048-57. [DOI: 10.1111/j.1462-2920.2011.02670.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mitchell SO, Steinum T, Rodger H, Holland C, Falk K, Colquhoun DJ. Epitheliocystis in Atlantic salmon, Salmo salar L., farmed in fresh water in Ireland is associated with 'Candidatus Clavochlamydia salmonicola' infection. JOURNAL OF FISH DISEASES 2010; 33:665-673. [PMID: 20629856 DOI: 10.1111/j.1365-2761.2010.01171.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Intracellular inclusions containing chlamydia-like organisms are frequently observed in the gill epithelial cells of Atlantic salmon, Salmo salar L., cultured in fresh water in Ireland. In this study, the causative agent was identified in four separate freshwater sites, using 16s rRNA sequencing, as 'Candidatus Clavochlamydia salmonicola'. Histopathology and real-time (RT) PCR were used to further assess infections. The prevalence of infection ranged from 75-100% between sites and infection intensity was highly variable. No significant lesions were associated with these infections. As a diagnostic tool, RT-PCR proved marginally more sensitive than histopathology. The fate of 'Candidatus Clavochlamydia salmonicola' in Atlantic salmon post-seawater transfer was investigated in a 12-week marine longitudinal study. Both RT-PCR and histopathological examination indicate that the organism disappears from the gills 4-6 weeks post-transfer.
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