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Lei S, Gu X, Xue W, Rong Z, Wang Z, Chen S, Zhong Q. A 4-plex Droplet Digital PCR Method for Simultaneous Quantification and Differentiation of Pathogenic and Non-pathogenic Vibrio parahaemolyticus Based on Single Intact Cells. Front Microbiol 2020; 11:1727. [PMID: 32903334 PMCID: PMC7434843 DOI: 10.3389/fmicb.2020.01727] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/01/2020] [Indexed: 01/17/2023] Open
Abstract
Vibrio parahaemolyticus is a significant seafood-borne pathogen, leading to serious acute gastrointestinal diseases worldwide. In this study, a reliable 4-plex droplet digital PCR (ddPCR) was successfully established and evaluated for the simultaneous detection of V. parahaemolyticus based on tlh, tdh, ureR, and orf8 in food samples using single intact cells. The targets tlh and ureR were labeled with 6-Carboxyfluorescein (FAM), and the targets tdh and orf8 were labeled with 5’-Hexachlorofluorescein (HEX). Due to reasonable proration of primers and probes corresponding into the two fluorescence channels of the ddPCR detecting platforms, the clearly separated 16 (24) clusters based on fluorescence amplitude were obtained. For better results, the sample hot lysis time and the cycle number were optimized. The results showed that the minimum number of “rain” and maximum fluorescence amplification were presented for precise detection in the condition of 25 min of the sample hot lysis time and 55 cycles. The sensitivity of this 4-plex ddPCR assay was 39 CFU/mL, which was in accordance with that of the conventional plate counting and was 10-fold sensitive than that of qPCR. In conclusion, the 4-plex ddPCR assay presented in this paper was a rapid, specific, sensitive, and accurate tool for the detection of V. parahaemolyticus including pandemic group strains and could be applied in the differentiation of V. parahaemolyticus in a wide variety of samples.
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Affiliation(s)
- Shuwen Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Xiaokui Gu
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, China.,Guangdong Shunde Innovative Design Institute, Foshan, China
| | - Wei Xue
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, China
| | - Zhangquan Rong
- Guangdong Shunde Innovative Design Institute, Foshan, China
| | - Zhe Wang
- Guangdong Shunde Innovative Design Institute, Foshan, China
| | - Song Chen
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou, China
| | - Qingping Zhong
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
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Zhang L, Li Z, Li Y, Tian J, Jia K, Zhang D, Song M, Abbas Raza SH, Garcia M, Kang Y, Zheng W, Qian A, Shan X, Xu Y. OmpW expressed by recombinant Lactobacillus casei elicits protective immunity against Aeromonas veronii in common carp. Microb Pathog 2019; 133:103552. [PMID: 31121269 DOI: 10.1016/j.micpath.2019.103552] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/16/2019] [Accepted: 05/19/2019] [Indexed: 12/22/2022]
Abstract
Aeromonas veronii is an opportunistic pathogen that is capable of infecting both aquatic livestock and mammals. Natural infection in fishes results in irreparable damage to the aquaculture industry. In this study, we sought to investigate whether recombinant Lactobacillus casei expressing the outer membrane protein W (OmpW) of A.veronii could elicit protective immunity against A.veronii infections. We generated two recombinant Lactobacillus casei (L.casei) strains expressing the OmpW of A.veronii (surface-displayed or secreted) and evaluated the effect on immune responses in a fish model. A 600-bp gene fragment was subcloned into the L.casei expression plasmids pPG-1 (surface-displayed) and pPG-2 (secreted). Expression of the recombinant OmpW protein was also confirmed by Western blot and immunofluorescence assays. Common carp immunized with Lc-pPG-1- OmpW and Lc-pPG-2- OmpW via oral administration elicited high serum specific antibody titers and high LZM, ACP, and SOD activities. High levels of the IL-10, IL-β, IFN-γ, and TNF-α genes in different organs indicated that the inflammatory response and cell immune response were triggered. Additionally, when immunized fish were challenged with A.veronii, Lc-pPG1-OmpW and Lc-pPG2-OmpW demonstrated 40% and 50% protective efficacy. These data indicate that the combination of OmpW delivery and the lactic acid bacteria (LAB) approach may be a promising mucosal therapeutic strategy for treatment of A.veronii.
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Affiliation(s)
- Lei Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Zhenxing Li
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Ying Li
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Jiaxin Tian
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Kaixiang Jia
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Dongxing Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Mingfang Song
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Sayed Haidar Abbas Raza
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shanxi, 712100, PR China
| | - Matthew Garcia
- Utah State University, School of Animal Dairy and Veterinary Sciences, Logan Utah USA, 84322, USA
| | - Yuanhuan Kang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Wei Zheng
- Jilin Province Fisheries Research Institute, Changchun, 130000, China
| | - Aidong Qian
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Xiaofeng Shan
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
| | - Yang Xu
- Agriculture Ministry Key Laboratory of Healthy Freshwater Aquaculture, Key Laboratory of Freshwater Aquaculture Genetic and Breeding of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries, Huzhou, 313001, China.
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Paria P, Chakraborty HJ, Behera BK, Das Mohapatra PK, Das BK. Computational characterization and molecular dynamics simulation of the thermostable direct hemolysin-related hemolysin (TRH) amplified from Vibrio parahaemolyticus. Microb Pathog 2018; 127:172-182. [PMID: 30503957 DOI: 10.1016/j.micpath.2018.11.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/24/2018] [Accepted: 11/26/2018] [Indexed: 01/08/2023]
Abstract
Vibrio parahaemolyticus is a major seafood-borne pathogen that causes life-threatening gastroenteric diseases in humans through the consumption of contaminated seafoods. V. parahaemolyticus produces different kinds of toxins, including thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH), and some effector proteins belonging to the Type 3 Secretion System, out of which TDH and TRH are considered to be the major factors for virulence. Although TRH is one of the major virulent proteins, there is a dearth of understanding about the structural and functional properties of this protein. This study therefore aimed to amplify the full length trh gene from V. parahaemolyticus and perform sequence-based analyses, followed by structural and functional analyses of the TRH protein using different bioinformatics tools. The TRH protein shares significant conservedness with the TDH protein. A multiple sequence alignment of TRH proteins from Vibrio and non-Vibrio species revealed that the TRH protein is highly conserved throughout evolution. The three dimensional (3D) structure of the TRH protein was constructed by comparative modelling and the quality of the predicted model was verified. Molecular dynamics simulations were performed to understand the dynamics, residual fluctuations, and the compactness of the protein. The structure of TRH was found to contain 19 pockets, of which one (pocket ID: 2) was predicted to be important from the view of drug design. Eleven residues (E138, Y140, C151, F158, C161, K162, S163, and Q164), which are reported to actively participate in the formation of the tetrameric structure, were present in this pocket. This study extends our understanding of the structural and functional dynamics of the TRH protein and as well as provides new insights for the treatment and prevention of V. parahaemolyticus infections.
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Affiliation(s)
- Prasenjit Paria
- Biotechnology Laboratory, ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, 700120, West Bengal, India; Department of Microbiology, Vidyasagar University, Midnapure, 721102, West Bengal, India
| | - Hirak Jyoti Chakraborty
- Biotechnology Laboratory, ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, 700120, West Bengal, India
| | - Bijay Kumar Behera
- Biotechnology Laboratory, ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, 700120, West Bengal, India.
| | | | - Basanta Kumar Das
- Biotechnology Laboratory, ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, 700120, West Bengal, India
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Nilsson WB, Turner JW. The thermostable direct hemolysin-related hemolysin (trh) gene of Vibrio parahaemolyticus: Sequence variation and implications for detection and function. J Microbiol Methods 2016; 126:1-7. [PMID: 27094247 DOI: 10.1016/j.mimet.2016.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 02/08/2023]
Abstract
Vibrio parahaemolyticus is a leading cause of bacterial food-related illness associated with the consumption of undercooked seafood. Only a small subset of strains is pathogenic. Most clinical strains encode for the thermostable direct hemolysin (TDH) and/or the TDH-related hemolysin (TRH). In this work, we amplify and sequence the trh gene from over 80 trh+strains of this bacterium and identify thirteen genetically distinct alleles, most of which have not been deposited in GenBank previously. Sequence data was used to design new primers for more reliable detection of trh by endpoint PCR. We also designed a new quantitative PCR assay to target a more conserved gene that is genetically-linked to trh. This gene, ureR, encodes the transcriptional regulator for the urease gene cluster immediately upstream of trh. We propose that this ureR assay can be a useful screening tool as a surrogate for direct detection of trh that circumvents challenges associated with trh sequence variation.
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Affiliation(s)
- William B Nilsson
- Environmental and Fisheries Science Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd. E., Seattle, WA 98112, USA.
| | - Jeffrey W Turner
- Environmental and Fisheries Science Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd. E., Seattle, WA 98112, USA
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Raghunath P. Roles of thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) in Vibrio parahaemolyticus. Front Microbiol 2015; 5:805. [PMID: 25657643 PMCID: PMC4302984 DOI: 10.3389/fmicb.2014.00805] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 12/30/2014] [Indexed: 01/08/2023] Open
Abstract
Vibrio parahaemolyticus is the leading cause of seafood borne bacterial gastroenteritis in the world, often associated with the consumption of raw or undercooked seafood. However, not all strains of V. parahaemolyticus are pathogenic. The thermostable direct hemolysin (TDH) or TDH-related hemolysin (TRH) encoded by tdh and trh genes, respectively, are considered major virulence factors in V. parahaemolyticus. However, about 10% of clinical strains do not contain tdh and/or trh. Environmental isolates of V. parahaemolyticus lacking tdh and/or trh are also highly cytotoxic to human gastrointestinal cells. Even in the absence of these hemolysins, V. parahaemolyticus remains pathogenic indicating other virulence factors exist. This mini review aims at discussing the possible roles of tdh and trh genes in clinical and environmental isolates of V. parahaemolyticus.
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Affiliation(s)
- Pendru Raghunath
- Department of Microbiology, Dr. VRK Women's Medical College Teaching Hospital and Research Centre Hyderabad, India
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Ceccarelli D, Hasan NA, Huq A, Colwell RR. Distribution and dynamics of epidemic and pandemic Vibrio parahaemolyticus virulence factors. Front Cell Infect Microbiol 2013; 3:97. [PMID: 24377090 PMCID: PMC3858888 DOI: 10.3389/fcimb.2013.00097] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/23/2013] [Indexed: 12/18/2022] Open
Abstract
Vibrio parahaemolyticus, autochthonous to estuarine, marine, and coastal environments throughout the world, is the causative agent of food-borne gastroenteritis. More than 80 serotypes have been described worldwide, based on antigenic properties of the somatic (O) and capsular (K) antigens. Serovar O3:K6 emerged in India in 1996 and subsequently was isolated worldwide, leading to the conclusion that the first V. parahaemolyticus pandemic had taken place. Most strains of V. parahaemolyticus isolated from the environment or seafood, in contrast to clinical strains, do not produce a thermostable direct hemolysin (TDH) and/or a TDH-related hemolysin (TRH). Type 3 secretion systems (T3SSs), needle-like apparatuses able to deliver bacterial effectors into host cytoplasm, were identified as triggering cytotoxicity and enterotoxicity. Type 6 secretion systems (T6SS) predicted to be involved in intracellular trafficking and vesicular transport appear to play a role in V. parahaemolyticus virulence. Recent advances in V. parahaemolyticus genomics identified several pathogenicity islands (VpaIs) located on either chromosome in both epidemic and pandemic strains and comprising additional colonization factors, such as restriction-modification complexes, chemotaxis proteins, classical bacterial surface virulence factors, and putative colicins. Furthermore, studies indicate strains lacking toxins and genomic regions associated with pathogenicity may also be pathogenic, suggesting other important virulence factors remain to be identified. The unique repertoire of virulence factors identified to date, their occurrence and distribution in both epidemic and pandemic strains worldwide are described, with the aim of highlighting the complexity of V. parahaemolyticus pathogenicity as well as its dynamic genome.
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Affiliation(s)
- Daniela Ceccarelli
- Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA
| | - Nur A Hasan
- Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA ; CosmosID Inc. College Park, MD, USA
| | - Anwar Huq
- Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA ; Maryland Institute of Applied Environmental Health, University of Maryland College Park, MD, USA
| | - Rita R Colwell
- Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA ; CosmosID Inc. College Park, MD, USA ; Maryland Institute of Applied Environmental Health, University of Maryland College Park, MD, USA ; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA
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Rosec JP, Causse V, Cruz B, Rauzier J, Carnat L. The international standard ISO/TS 21872-1 to study the occurence of total and pathogenic Vibrio parahaemolyticus and Vibrio cholerae in seafood: ITS improvement by use of a chromogenic medium and PCR. Int J Food Microbiol 2012; 157:189-94. [PMID: 22682545 DOI: 10.1016/j.ijfoodmicro.2012.04.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 11/18/2022]
Abstract
During two surveys conducted in 2008 and 2009, the culture method described in the international standard ISO/TS 21872-1 was applied to the detection of Vibrio parahaemolyticus and Vibrio cholerae in 112 living bivalve mollusc samples, with a chromogenic medium used in addition to the TCBS agar, as second selective isolation medium and for enumeration of V. parahaemolyticus and V. cholerae by surface inoculation. A PCR method for detection of these 2 Vibrio species and the hemolysin genes tdh and trh, was applied in parallel. In 2009, the survey was extended to finfish fillets and crustaceans. PCR was also used for species confirmation of characteristic colonies. The identity of the PCR products, specifically targeting V. parahaemolyticus, was checked by sequencing. Occurrence of V. parahaemolyticus and V. cholerae isolates in living bivalve molluscs ranged from 30.4% to 32.6% and from 1.4% to 4.7% respectively. In frozen crustaceans (2009 survey) V. parahaemolyticus and V. cholerae isolates were respectively found in 45% and 10% of the samples. No V. parahaemolyticus or V. cholerae was detected in frozen fish fillets, neither by the ISO method nor by PCR. In 2009, enteropathogenic V. parahaemolyticus (trh+) was isolated from 4 out of 43 oyster samples while the trh gene was present in V. alginolyticus strains and in samples where V. parahaemolyticus was not detected (9 over 112 samples). The ISO method failed to isolate V. parahaemolyticus in 44% to 53% of the living bivalve molluscs where PCR detected the toxR gene specific of V. parahaemolyticus (Vp-toxR). Our results highlighted the need for a revision of the ISO/TS 21872-1 standard, at least, for analysis of living bivalve molluscs, and confirmed the increasing concern of enteropathogenic V. parahaemolyticus in French bivalve molluscs. Enrichment at 41.5°C was questioned and some reliable solutions for the improvement of the ISO/TS 21872-1 method, such as the PCR method for screening of positive samples and confirmation of colonies, were pointed out.
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Affiliation(s)
- Jean-Philippe Rosec
- Service Commun des Laboratoires-Laboratoire de Montpellier-Unité Biologie, Montpellier, France.
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Bisha B, Simonson J, Janes M, Bauman K, Goodridge LD. A review of the current status of cultural and rapid detection of Vibrio parahaemolyticus. Int J Food Sci Technol 2012. [DOI: 10.1111/j.1365-2621.2012.02950.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Singh V, Mani I, Chaudhary DK, Somvanshi P. Molecular detection and cloning of thermostable hemolysin gene from Aeromonas hydrophila. Mol Biol 2011. [DOI: 10.1134/s002689331104011x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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