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102
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Mahmoud BS. Reduction of Vibrio vulnificus in pure culture, half shell and whole shell oysters (Crassostrea virginica) by X-ray. Int J Food Microbiol 2009; 130:135-9. [DOI: 10.1016/j.ijfoodmicro.2009.01.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 01/20/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
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103
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Kodaka H, Teramura H, Mizuochi S, Saito M, Matsuoka H. Evaluation of the Compact Dry VP method for screening raw seafood for total Vibrio parahaemolyticus. J Food Prot 2009; 72:169-73. [PMID: 19205480 DOI: 10.4315/0362-028x-72.1.169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Compact Dry VP (CDVP) is a ready-to-use method for enumerating Vibrio parahaemolyticus in food. The presterilized plates contain a culture medium comprising peptone, NaCl, bile salts, antibiotics, chromogenic substrates, and polysaccharide gum as a cold water-soluble gelling. After diluting raw seafood samples in a phosphate-buffered saline solution, a 1-ml aliquot was inoculated onto the center of the plate and allowed to diffuse by capillary action. Blue-green colonies forming on the plates were counted after 18 to 20 h of incubation at 35 degrees C. A total of 85 V. parahaemolyticus strains (62 tdh+ strains and 23 tdh- strains) were studied for inclusivity, 81 (95.3 %) of which produced blue-green colonies. When 97 strains (14 strains of Vibrio spp., 33 strains of coliform bacteria, and 50 strains of noncoliform bacteria) were assessed for exclusivity, 10 strains of Vibrio spp. produced non-blue-green colonies, and 87 strains failed to grow. The CDVP and U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA-BAM) methods were compared with the use of four different types of raw seafood that were inoculated with four different V. parahaemolyticus strains. For raw tuna and oysters, the FDA-BAM colony lift method was used, whereas the FDA-BAM most-probable-number method was used for salmon and scallop. The linear correlation coefficients between the CDVP and FDA-BAM methods were 0.99 for fresh raw tuna, 0.95 for fresh raw oysters, 0.95 for frozen raw salmon, and 0.95 for frozen raw scallops. These results suggest that the CDVP method is useful for screening raw seafood for V. parahaemolyticus.
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Affiliation(s)
- Hidemasa Kodaka
- Research Institute of Advanced Technology, Nissui Pharmaceutical Co. Ltd., Yuki, Ibaraki 307-0036, Japan.
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104
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Abstract
PCR screening of the shellfish-borne pathogen Vibrio vulnificus revealed csrA-negative strains, and these strains formed increased biofilm compared to csrA-positive strains. Complementation in trans with csrA resulted in reduced biofilm formation, similar to that by csrA(+) strains. Our results provide evidence that csrA inhibits biofilm formation in V. vulnificus.
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105
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Emerging Vibrio species: an unending threat to public health in developing countries. Res Microbiol 2008; 159:495-506. [PMID: 18692131 DOI: 10.1016/j.resmic.2008.07.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 06/06/2008] [Accepted: 07/04/2008] [Indexed: 11/23/2022]
Abstract
Discharge of inadequately treated sewage effluents into the environment in developing countries has increased over the years, leading to deterioration of water quality of major watersheds in developing nations and consequently an increased incidence of emerging pathogens such as Vibrio species, the prevalence of which has been generally underestimated in developing nations. This review underscores the need for a proactive approach to risk factors for emerging Vibrio infections, so as to establish adequate prevention measures.
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106
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Hsieh JL, Fries JS, Noble RT. Dynamics and predictive modelling of Vibrio spp. in the Neuse River Estuary, North Carolina, USA. Environ Microbiol 2008; 10:57-64. [PMID: 18211266 DOI: 10.1111/j.1462-2920.2007.01429.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vibrio spp. are naturally occurring bacteria in marine and estuarine environments around the world. The genus includes several human and animal pathogens that can negatively impact human health, seafood and aquaculture. Vibrio spp. populations are capable of rapid adaptation in response to changing environmental conditions, making them dynamic over short-term and seasonal scales. Temperature, vertical mixing, tidal flushing, climate, precipitation and nutrient loading can change the estuarine environment and subsequently alter microbial community structure, including Vibrio spp., affecting estuarine water quality and public health. To describe these dynamics, Vibrio spp. concentrations and a range of microbial, physical and chemical measures were monitored every 2 weeks and after storm events for 19 months in the Neuse River Estuary (NRE). Results showed clear seasonal and geographic trends in Vibrio spp. abundance. Multiple regression analysis revealed a strong relationship to temperature and salinity, with additional minor influences of chlorophyll a and dissolved organic carbon. Similar models based on easily measured environmental parameters should be pursued for individual Vibrio species in the NRE and other estuarine environments. Predictive models provide useful information for managers, researchers and modellers of estuarine ecosystems.
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Affiliation(s)
- Jennifer L Hsieh
- UNC Chapel Hill, Institute of Marine Sciences, 3431 Arendell Street, Morehead City, NC 28557, USA
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107
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Inoue Y, Ono T, Matsui T, Miyasaka J, Kinoshita Y, Ihn H. Epidemiological survey of Vibrio vulnificus infection in Japan between 1999 and 2003. J Dermatol 2008; 35:129-39. [PMID: 18346255 DOI: 10.1111/j.1346-8138.2008.00432.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The frequency of Vibrio vulnificus infection is very rare and there are many questions regarding its epidemiology in Japan. To investigate the clinical course and epidemiology of V. vulnificus infection in Japan, we performed a retrospective questionnaire survey in which 1693 hospitals from all over Japan were surveyed, including advanced life saving emergency centers and dermatology institutions. Of the 1693 hospitals, we received answers from 1045. Ninety-four cases were confirmed as V. vulnificus infections during 1999 and 2003. Sixty-eight (72.3%) of the 94 patients had the septic type infection with a mortality rate of 75.0% (51/68 patients died). The prognosis of patients with the septic type was worse than that of the wound type (P < 0.001). V. vulnificus infections occurred from June to November and none occurred in winter. Many infections occurred in western Japan with the majority of infections (50/94) occurring in Kyushu. In particular, 43 infections occurred in marine coastal areas of the Ariake and Yatsushiro Seas, which have many tidelands. Seventy-seven of 89 patients (86.5%) had liver function impairment as an underlying disease, and 53 (59.6%) had liver cirrhosis, of whom nine (10.1%) suffered from liver cancer. The incidence of V. vulnificus infection was different according to districts. Geographic and climatic factors also contributed to the occurrence of V. vulnificus infection.
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Affiliation(s)
- Yuji Inoue
- Department of Dermatology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
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108
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The ecology of Vibrio vulnificus, Vibrio cholerae, and Vibrio parahaemolyticus in North Carolina estuaries. J Microbiol 2008; 46:146-53. [PMID: 18545963 DOI: 10.1007/s12275-007-0216-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2007] [Accepted: 02/06/2008] [Indexed: 12/19/2022]
Abstract
While numerous studies have characterized the distribution and/or ecology of various pathogenic Vibrio spp., here we have simultaneously examined several estuarine sites for Vibrio vulnificus, V. cholerae, and V. parahaemolyticus. For a one year period, waters and sediment were monitored for the presence of these three pathogens at six different sites on the east coast of North Carolina in the United States. All three pathogens, identified using colony hybridization and PCR methods, occurred in these estuarine environments, although V. cholerae occurred only infrequently and at very low levels. Seventeen chemical, physical, and biological parameters were investigated, including salinity, water temperature, turbidity, dissolved oxygen, levels of various inorganic nutrients and dissolved organic carbon, as well as total vibrios, total coliforms, and E. coli. We found each of the Vibrio spp. in water and sediment to correlate to several of these environmental measurements, with water temperature and total Vibrio levels correlating highly (P<0.0001) with occurrence of the three pathogens. Thus, these two parameters may represent simple assays for characterizing the potential public health hazard of estuarine waters.
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109
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Cyclic-di-GMP regulates extracellular polysaccharide production, biofilm formation, and rugose colony development by Vibrio vulnificus. Appl Environ Microbiol 2008; 74:4199-209. [PMID: 18487410 DOI: 10.1128/aem.00176-08] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Vibrio vulnificus is a human and animal pathogen that carries the highest death rate of any food-borne disease agent. It colonizes shellfish and forms biofilms on the surfaces of plankton, algae, fish, and eels. Greater understanding of biofilm formation by the organism could provide insight into approaches to decrease its load in filter feeders and on biotic surfaces and control the occurrence of invasive disease. The capsular polysaccharide (CPS), although essential for virulence, is not required for biofilm formation under the conditions used here. In other bacteria, increased biofilm formation often correlates with increased exopolysaccharide (EPS) production. We exploited the translucent phenotype of acapsular mutants to screen a V. vulnificus genomic library and identify genes that imparted an opaque phenotype to both CPS biosynthesis and transport mutants. One of these encoded a diguanylate cyclase (DGC), an enzyme that synthesizes bis-(3'-5')-cyclic-di-GMP (c-di-GMP). This prompted us to use this DGC, DcpA, to examine the effect of elevated c-di-GMP levels on several developmental pathways in V. vulnificus. Increased c-di-GMP levels induced the production of an EPS that was distinct from the CPS and dramatically enhanced biofilm formation and rugosity in a CPS-independent manner. However, the EPS could not compensate for the loss of CPS production that is required for virulence. In contrast to V. cholerae, motility and virulence appeared unaffected by elevated levels of c-di-GMP.
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110
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Mahmud ZH, Neogi SB, Kassu A, Mai Huong BT, Jahid IK, Islam MS, Ota F. Occurrence, seasonality and genetic diversity of Vibrio vulnificus in coastal seaweeds and water along the Kii Channel, Japan. FEMS Microbiol Ecol 2008; 64:209-18. [PMID: 18355295 DOI: 10.1111/j.1574-6941.2008.00460.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Vibrio vulnificus is a ubiquitous toxigenic bacterium found in a coastal environment but little is known about its occurrence and seasonality among seaweeds, which are widely consumed as seafood in Japan. Therefore, we have observed the bacterium's abundance in seawater and seaweed samples from three areas of the Kii Channel, Japan, during June 2003 to May 2004. A total of 192 samples were collected: 24 from each source in summer, autumn, winter and spring. The samples were selectively cultivated following the most probable number (MPN) technique. Vibrio vulnificus population ranged from 0 to 10(3) MPN 100 mL(-1) seawater or 10 g seaweeds; higher counts were observed during summer. The optimum temperature, salinity and pH for the bacterium were 20-24 degrees C, 24-28 p.p.t. and 7.95-8.15, respectively. However, seaweeds always contained higher V. vulnificus than seawater. Among 280 V. vulnificus strains, detected by species-specific colony hybridization and PCR, 78, 74, 11 and 16 were from seaweeds and 46, 42, 2 and 11 were from seawater during summer, autumn, winter and spring, respectively. Ribotyping of 160 selected strains revealed a higher genotypic diversity (18 patterns) among strains from seaweeds than from seawater (10 patterns). Seaweeds can thus act as a potential habitat for V. vulnificus and are more unsafe for consumption during summer.
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Affiliation(s)
- Zahid Hayat Mahmud
- Environmental Microbiology Laboratory, Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh.
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111
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Pushpamali WA, De Zoysa M, Kang HS, Oh CH, Whang I, Kim SJ, Lee J. Comparative study of two thioredoxin peroxidases from disk abalone (Haliotis discus discus): cloning, recombinant protein purification, characterization of antioxidant activities and expression analysis. FISH & SHELLFISH IMMUNOLOGY 2008; 24:294-307. [PMID: 18226547 DOI: 10.1016/j.fsi.2007.11.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/22/2007] [Accepted: 11/22/2007] [Indexed: 05/25/2023]
Abstract
Thioredoxin peroxidase (TPx), also named peroxiredoxin (Prx), is an important peroxidase, which can protect organisms against various oxidative stresses. Two TPxs were isolated from a disk abalone (Haliotis discus discus) cDNA library, named as AbTPx1 and AbTPx2, respectively. AbTPx1 and AbTPx2 consist of 1315 and 1045 bp full-length cDNA with 753 and 597 bp open reading frames encoding 251 and 199 amino acids, respectively. The TPx signature motif 1 (FYPLDFTFVCPTEI) and motif 2 (GEVCPA) were conserved in both AbTPx1 and AbTPx2 amino acid sequences. Purified recombinant abalone TPx fusion proteins catalyzed the reduction of H2O2 and butyl hydroperoxide in peroxidase assays. Furthermore, both AbTPx fusion proteins were shown to protect super-coiled DNA from damage by metal-catalyzed oxidation (MCO) in vitro. Escherichia coli cells transformed with AbTPx1 and AbTPx2 coding sequences in pMAL-c2x showed resistance to H2O2 at 0.8 mM concentration by in vivo H2O2 tolerance assay. AbTPx1 and AbTPx2 mRNA were constitutively expressed in gill, mantle, abductor muscle and digestive tract in a tissue specific manner. Additionally, both TPxs mRNA were up-regulated in gill and digestive tract tissues against H2O2 at 3h post injection. The results indicate that AbTPx1 and AbTPx2 gene expressions are induced by oxidative stress and their respective proteins function in the detoxification of different ROS molecules to maintain efficient antioxidant defense in disk abalone.
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112
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Population structures of two genotypes of Vibrio vulnificus in oysters (Crassostrea virginica) and seawater. Appl Environ Microbiol 2007; 74:80-5. [PMID: 17993556 DOI: 10.1128/aem.01434-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus biotype 1 strains can be classified into two genotypes based on the PCR analysis of variations in the virulence-correlated gene (vcg). Genotype has been correlated with human infection for 90% of isolates from human cases having the vcgC sequence type and 87% of environmental strains having the vcgE variant. In this study we examined the dynamics of V. vulnificus populations and the distribution of the two genotypes recovered from oysters and surrounding estuarine wasters. Analysis of 880 isolates recovered from oysters showed a disparity in the ratio of the two genotypes, with those of the vcgE (E) genotype accounting for 84.4% of the population. In contrast, 292 isolates recovered from the waters surrounding the oyster sites revealed an almost equal distribution of the two genotypes. The levels of vcgC (C genotype) strains from both sources increased as a percentage of the population as water temperatures increased, while no culturable V. vulnificus cells were recovered from December through February. Our results suggest that there is a selective advantage for strains of the E genotype within oysters while survival of the C genotype strains may be favored by increased water column temperatures. These data suggest that the low incidence of infections may be due to the comparatively rare consumption of an oyster that contains a greater number of V. vulnificus vcgC genotype strains than of vcgE genotype strains. Levels of the two genotypes as well as seasonal dynamics within both oyster tissue and the surrounding waters may aid in identifying risk factors associated with human infection.
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113
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Survival of and in situ gene expression by Vibrio vulnificus at varying salinities in estuarine environments. Appl Environ Microbiol 2007; 74:182-7. [PMID: 17993554 DOI: 10.1128/aem.02436-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The opportunistic human pathogen Vibrio vulnificus survives in a wide range of ecological environments, which demonstrates its ability to adapt to highly variable conditions. Survival and gene expression under various conditions have been extensively studied in vitro; however, little work has been done to evaluate this bacterium in its natural habitat. Therefore, this study monitored the long-term survival of V. vulnificus in situ and simultaneously evaluated the expression of stress (rpoS, relA, hfq, and groEL) and putative virulence (vvpE, smcR, viuB, and trkA) genes at estuarine sites of varying salinity. Additionally, the survival and gene expression of an rpoS and an oxyR mutant were examined under the same conditions. Differences between the sampling sites in the long-term survival of any strain were not seen. However, differences were seen in the expression of viuB, trkA, and relA but our findings differed from what has been previously shown in vitro. These results also routinely demonstrated that genes required for survival under in vitro stress or host conditions are not necessarily required for survival in the water column. Overall, this study highlights the need for further in situ evaluation of this bacterium in order to gain a true understanding of its ecology and how it relates to its natural habitat.
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114
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De Zoysa M, Lee J. Molecular cloning and expression analysis of interferon-γ inducible lysosomal thiol reductase (GILT)-like cDNA from disk abalone (Haliotis discus discus). J Invertebr Pathol 2007; 96:221-9. [PMID: 17599346 DOI: 10.1016/j.jip.2007.05.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 05/05/2007] [Accepted: 05/22/2007] [Indexed: 11/28/2022]
Abstract
Interferon Gamma (IFN-gamma) Inducible Lysosomal Thiol reductase (GILT) has been described as a key enzyme in processing and presentation of major histocompatibility complex (MHC) class II restricted antigen (Ag) by catalyzing disulfide bond (S-S) reduction in mammals. Abalone GILT-like (AbGILT) full-length cDNA was isolated from the normalized disk abalone cDNA library. The 807-bp AbGILT cDNA consists of an open reading frame of 684-bp, encoding 228 amino acid residues. The predicted AbGILT protein has a molecular weight of 25kDa and an isoelectric point of 7.8. The N-terminus of the AbGILT was found to have a putative signal peptide with a cleavage site amino acid position at 19-20. AbGILT contains two active site C-XX-C motifs, ((23)CLDC(26) and (46)CPYC(49)) which motif is highly conserved in GILT protein family. AbGILT exhibited a characteristic GILT signature sequence (92)CQHGX(2)ECX(2)NX(4)C(107) and 12 cysteine residues representing 5% in the mature peptide. Phylogenetic analysis showed that AbGILT has been derived from a common ancestor with other GILT proteins. RT-PCR results showed that AbGILT expression was up-regulated in the gill, mantle and digestive tract 24h post injection of phytohemagglutinin (PHA) while Vibrio alginolyticus up-regulation appeared in the gill and digestive tract after 48h. In contrast, AbGILT expression was not up-regulated by poly inosinic-cytidylic acid (poly I:C) during the 48h induction. However, AbGILT was constitutively expressed in gill, mantle, and digestive tract tissues suggesting that it may maintain first line of innate immune defense at basal level in disk abalone.
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Affiliation(s)
- Mahanama De Zoysa
- Department of Marine Biotechnology, College of Ocean Science, Cheju National University, Jeju 690-756, Republic of Korea
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115
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Wright AC, Garrido V, Debuex G, Farrell-Evans M, Mudbidri AA, Otwell WS. Evaluation of postharvest-processed oysters by using PCR-based most-probable-number enumeration of Vibrio vulnificus bacteria. Appl Environ Microbiol 2007; 73:7477-81. [PMID: 17905883 PMCID: PMC2168190 DOI: 10.1128/aem.01118-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 09/18/2007] [Indexed: 11/20/2022] Open
Abstract
Postharvest processing (PHP) is used to reduce levels of Vibrio vulnificus in oysters, but process validation is labor-intensive and expensive. Therefore, quantitative PCR was evaluated as a rapid confirmation method for most-probable-number enumeration (QPCR-MPN) of V. vulnificus bacteria in PHP oysters. QPCR-MPN showed excellent correlation (R(2) = 0.97) with standard MPN and increased assay sensitivity and efficiency.
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Affiliation(s)
- Anita C Wright
- University of Florida, Department of Food Science and Human Nutrition, P.O. Box 110370, Gainesville, FL 32611, USA.
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116
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Drake SL, DePaola A, Jaykus LA. An Overview of Vibrio vulnificus and Vibrio parahaemolyticus. Compr Rev Food Sci Food Saf 2007. [DOI: 10.1111/j.1541-4337.2007.00022.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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117
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Paranjpye RN, Johnson AB, Baxter AE, Strom MS. Role of type IV pilins in persistence of Vibrio vulnificus in Crassostrea virginica oysters. Appl Environ Microbiol 2007; 73:5041-4. [PMID: 17557854 PMCID: PMC1951050 DOI: 10.1128/aem.00641-07] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 06/01/2007] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is part of the natural estuarine microflora and accumulates in shellfish through filter feeding. It is responsible for the majority of seafood-associated fatalities in the United States mainly through consumption of raw oysters. Previously we have shown that a V. vulnificus mutant unable to express PilD, the type IV prepilin peptidase, does not express pili on the surface of the bacterium and is defective in adherence to human epithelial cells (R. N. Paranjpye, J. C. Lara, J. C. Pepe, C. M. Pepe, and M. S. Strom, Infect. Immun. 66:5659-5668, 1998). A mutant unable to express one of the type IV pilins, PilA, is also defective in adherence to epithelial cells as well as biofilm formation on abiotic surfaces (R. N. Paranjpye and M. S. Strom, Infect. Immun. 73:1411-1422, 2005). In this study we report that the loss of PilD or PilA significantly reduces the ability of V. vulnificus to persist in Crassostrea virginica over a 66-h interval, strongly suggesting that pili expressed by this bacterium play a role in colonization or persistence in oysters.
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118
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Broza YY, Danin-Poleg Y, Lerner L, Broza M, Kashi Y. Vibrio vulnificus typing based on simple sequence repeats: insights into the biotype 3 group. J Clin Microbiol 2007; 45:2951-9. [PMID: 17652479 PMCID: PMC2045284 DOI: 10.1128/jcm.00236-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is an opportunistic, highly invasive human pathogen with worldwide distribution. V. vulnificus strains are commonly divided into three biochemical groups (biotypes), most members of which are pathogenic. Simple sequence repeats (SSR) provide a source of high-level genomic polymorphism used in bacterial typing. Here, we describe the use of variations in mutable SSR loci for accurate and rapid genotyping of V. vulnificus. An in silico screen of the genomes of two V. vulnificus strains revealed thousands of SSR tracts. Twelve SSR with core motifs longer than 5 bp in a panel of 32 characterized and 56 other V. vulnificus isolates, including both clinical and environmental isolates from all three biotypes, were tested for polymorphism. All tested SSR were polymorphic, and diversity indices ranged from 0.17 to 0.90, allowing a high degree of discrimination among isolates (27 of 32 characterized isolates). Genetic analysis of the SSR data resulted in the clear distinction of isolates that belong to the highly virulent biotype 3 group. Despite the clonal nature of this new group, SSR analysis demonstrated high-level discriminatory power within the biotype 3 group, as opposed to other molecular methods that failed to differentiate these isolates. Thus, SSR are suitable for rapid typing and classification of V. vulnificus strains by high-throughput capillary electrophoresis methods. SSR (>/=5 bp) by their nature enable the identification of variations occurring on a small scale and, therefore, may provide new insights into the newly emerged biotype 3 group of V. vulnificus and may be used as an efficient tool in epidemiological studies.
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Affiliation(s)
- Yoav Y Broza
- Department of Biotechnology and Food Engineering, The Technion Haifa, Haifa 32000, Israel
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119
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Lhafi SK, Kühne M. Occurrence of Vibrio spp. in blue mussels (Mytilus edulis) from the German Wadden Sea. Int J Food Microbiol 2007; 116:297-300. [PMID: 17331605 DOI: 10.1016/j.ijfoodmicro.2007.01.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 01/29/2007] [Indexed: 10/23/2022]
Abstract
The present study aimed at determining the contamination of blue mussels grown in Germany with relevant bacterial organisms. Seasonal variations were examined. For that purpose, mussel samples were taken regularly between June 2004 and May 2005 in seven shellfish-growing areas of the German Wadden Sea. A total of 90 samples were analysed. The analysis included the compulsory microbiological parameters Escherichia coli and Salmonella spp., as well as the determination of the contamination with Vibrio spp. Although the analysed mussels complied with the legislation in force, potential human pathogens were detected in a wide range of samples. Vibrio spp. was detected in 74.4% of the samples analysed in this study. Among Vibrio isolates, Vibrio alginolyticus was the species most frequently detected (51.2%), followed by Vibrio parahaemolyticus (39.5%). Vibrio vulnificus was detected in 3.5% of the samples. V. parahaemolyticus and V. vulnificus were not found in samples collected at low water temperatures. The results indicate that blue mussels from shellfish-growing areas in the German Wadden Sea regularly contain pathogens relevant to public health. They also show that E. coli is not a reliable indicator for the contamination with Vibrio spp. To improve consumer protection, it therefore seems necessary to extend the analysis of mussels for direct human consumption by additional parameters.
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Affiliation(s)
- Soumaya Katherine Lhafi
- University of Veterinary Medicine Hannover, Institute of Food Quality and Food Safety, Bischofsholer Damm 15, Hannover, Germany
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120
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Screening for extracellular enzyme activities by bacteria isolated from samples collected in the Tyrrhenian Sea. ANN MICROBIOL 2007. [DOI: 10.1007/bf03175056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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121
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Chatzidaki-Livanis M, Hubbard MA, Gordon K, Harwood VJ, Wright AC. Genetic distinctions among clinical and environmental strains of Vibrio vulnificus. Appl Environ Microbiol 2006; 72:6136-41. [PMID: 16957239 PMCID: PMC1563656 DOI: 10.1128/aem.00341-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus causes rare but frequently fatal septicemia associated with raw oyster consumption by persons with underlying hepatic or immune system dysfunction. The virulence potential of environmental reservoirs appears widely distributed, because most strains are virulent in animal models; however, several investigations recently demonstrated genetic divergence among strains from clinical versus environmental origin at independent genetic loci. The present study used PCR to screen DNA polymorphisms in strains from environmental (n = 35) or clinical (n = 33) sources, and genomic relationships were determined by repetitive extragenic palindromic DNA PCR (rep-PCR) typing. Significant (P < 0.01) association was observed for typical "clinical" or "environmental" polymorphism profiles based on strain origin. Most oyster isolates (88%), including all of those with the "environmental" profile, also formed a single rep-PCR genogroup. Clinical isolates within this group did not have the typical "clinical" profile. On the other hand, clinical isolates with the typical polymorphism profile were distributed among multiple rep-PCR genogroups, demonstrating greater genetic diversity than was evident by profiling genetic polymorphisms. Wound isolates were genetically distinct from typical blood isolates by all assays. Strains from an outbreak of wound infections in Israel (biotype 3) were closely related to several U.S. strains by rep-PCR, indicating potential reservoirs of emerging disease. Strains genetically related to blood isolates appeared to be relatively rare in oysters, as only one had the "clinical" polymorphism profile or clustered by rep-PCR. However, this study was not an extensive survey, and more sampling using rep-PCR for sensitive genetic discrimination is needed to determine the virulence potential of environmental reservoirs.
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Affiliation(s)
- Maria Chatzidaki-Livanis
- University of Florida, Department of Food Science and Human Nutrition, P.O. Box 110370, Gainesville, FL 32611, USA
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122
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Maugeri TL, Carbone M, Fera MT, Gugliandolo C. Detection and differentiation of Vibrio vulnificus in seawater and plankton of a coastal zone of the Mediterranean Sea. Res Microbiol 2006; 157:194-200. [PMID: 16129581 DOI: 10.1016/j.resmic.2005.06.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/13/2005] [Accepted: 06/22/2005] [Indexed: 12/17/2022]
Abstract
Vibrio vulnificus, a human and animal pathogen, is present in low numbers in the Mediterranean Sea. Seawater and plankton samples were collected from a marine coastal zone of the Straits of Messina in the Mediterranean Sea (Italy) in order to investigate V. vulnificus as free-living (>0.2 microm) and associated with small (>64 microm) and large plankton (>200 microm) utilizing cultural and molecular techniques. Characteristic colonies, grown on thiosulfate, citrate, bile salts and sucrose agar plates, were identified using a biochemical protocol system. A PCR assay was used to confirm isolates and to directly detect V. vulnificus in environmental concentrated samples. Specific primers were used to target the structural cytotoxin/hemolysin gene and the variable regions of 16S rRNA species-specific for V. vulnificus. In addition, a tri-primer PCR of 16S rRNA was used for the differentiation of V. vulnificus strains. Direct detection in marine samples was more frequent than isolation of culturable forms. All isolates were assigned to V. vulnificus biotype 1, 16S rRNA type B. These results confirm the low incidence of V. vulnificus in Mediterranean coastal waters. The isolation of cultivable forms is limited to the warmest months. 16S rRNA primers were the most sensitive molecular tool as they allowed detection of V. vulnificus in 79.1% of samples. Due to the low incidence of V. vulnificus in the Mediterranean coastal environment, its detection requires a molecular approach. The occurrence of V. vulnificus as plankton-associated confirms the role of plankton as a potential reservoir for this pathogen.
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Affiliation(s)
- Teresa L Maugeri
- Dipartimento di Biologia Animale ed Ecologia Marina, Università di Messina, Salita Sperone 31, 98166 Messina, Italy.
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123
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Panicker G, Bej AK. Real-time PCR detection of Vibrio vulnificus in oysters: comparison of oligonucleotide primers and probes targeting vvhA. Appl Environ Microbiol 2005; 71:5702-9. [PMID: 16204478 PMCID: PMC1265985 DOI: 10.1128/aem.71.10.5702-5709.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared three sets of oligonucleotide primers and two probes designed for Vibrio vulnificus hemolysin A gene (vvhA) for TaqMan-based real-time PCR method enabling specific detection of Vibrio vulnificus in oysters. Two of three sets of primers with a probe were specific for the detection of all 81 V. vulnificus isolates by TaqMan PCR. The 25 nonvibrio and 12 other vibrio isolates tested were negative. However, the third set of primers, F-vvh1059 and R-vvh1159, with the P-vvh1109 probe, although positive for all V. vulnificus isolates, also exhibited positive cycle threshold (C(T)) values for other Vibrio spp. Optimization of the TaqMan PCR assay using F-vvh785/R-vvh990 or F-vvh731/R-vvh1113 primers and the P-vvh874 probe detected 1 pg of purified DNA and 10(3) V. vulnificus CFU/ml in pure cultures. The enriched oyster tissue homogenate did not exhibit detectable inhibition to the TaqMan PCR amplification of vvhA. Detection of 3 x 10(3) CFU V. vulnificus, resulting from a 5-h enrichment of an initial inoculum of 1 CFU/g of oyster tissue homogenate, was achieved with F-vvh785/R-vvh990 or F-vvh731/R-vvh1113 primers and P-vvh875 probe. The application of the TaqMan PCR using these primers and probe, exhibited detection of V. vulnificus on 5-h-enriched natural oysters harvested from the Gulf of Mexico. Selection of appropriate primers and a probe on vvhA for TaqMan-PCR-based detection of V. vulnificus in post-harvest-treated oysters would help avoid false-positive results, thus ensuring a steady supply of safe oysters to consumers and reducing V. vulnificus-related illnesses and deaths.
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Affiliation(s)
- Gitika Panicker
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Campbell Hall, Rm. 102, Birmingham, AL 35294-1170, USA
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124
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Quevedo AC, Smith JG, Rodrick GE, Wright AC. Ice immersion as a postharvest treatment of oysters for the reduction of Vibrio vulnificus. J Food Prot 2005; 68:1192-7. [PMID: 15954706 DOI: 10.4315/0362-028x-68.6.1192] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vibrio vulnificus produces serious illnesses that are commonly associated with shellfish consumption, particularly raw oysters. Ingestion can result in fatal septicemia in susceptible individuals with hepatitis, cirrhosis, immune dysfunction, diabetes, or hemochromatosis (metabolic iron overload). Therefore, postharvest treatments to reduce vibrio levels in oysters have been recommended. In this study, rapid chilling by immersion of unwashed whole oysters in ice for 3 h was assessed as a postharvest treatment for reduction of V. vulnificus. Treated oysters were subsequently refrigerated at 45 degrees F (7.2 degrees C), whereas control oysters were not iced but were maintained at 45 degrees F throughout the study. Homogenized meats were monitored for total heterotrophic aerobic bacteria, V. vulnificus, and fecal coliform content before and after treatment over a 2-week period. V. vulnificus was enumerated by DNA probe hybridization of colonies from standard plate counts on nonselective medium, and recovery was compared for several media. Loss of plating efficiency was observed on standard selective and differential media compared with nonselective agars. Numbers of V. vulnificus generally declined in treated samples compared with controls; however, increases in total heterotrophic bacteria and fecal coliforms were also observed in treated samples at some time points. This study does not support the use of ice immersion as a postharvest method because of the relatively small declines in V. vulnificus numbers and the possibility of concomitant increases in fecal coliform and total bacterial contamination.
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Affiliation(s)
- Ana C Quevedo
- University of Florida, Department of Food Science and Human Nutrition, P.O. Box 110370, Gainesville, Florida 32611, USA
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125
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Pruzzo C, Gallo G, Canesi L. Persistence of vibrios in marine bivalves: the role of interactions with haemolymph components. Environ Microbiol 2005; 7:761-72. [PMID: 15892695 DOI: 10.1111/j.1462-2920.2005.00792.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Marine bivalves are widespread in coastal environments and, due to their filter-feeding habit, they can accumulate large numbers of bacteria thus acting as passive carriers of human pathogens. Bivalves possess both humoral and cellular defence mechanisms that operate in a co-ordinated way to kill and eliminate infecting bacteria. Vibrio species are very abundant in coastal waters and are commonly isolated from edible bivalves tissues where they can persist after depuration processes in controlled waters. Such observations indicate that vibrios are regular components of bivalve microflora and that the molluscs can represent an important ecological niche for these bacteria. Here we tried to summarize data on the interactions between vibrios and bivalve haemolymph; the available evidence supports the hypothesis that persistence of bacteria in bivalve tissues depends, at least in part, on their sensitivity to the bactericidal activity of the haemolymph. Results obtained with an in vitro model of Vibrio cholerae challenged against Mytilus galloprovincialis haemocytes indicate that bacterial surface components, soluble haemolymph factors and the signalling pathways of the haemocyte host are involved in determining the result of vibrio-haemolymph interactions.
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Affiliation(s)
- Carla Pruzzo
- Dipartimento di Biologia, Università di Genova, Genova, Italy.
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126
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Paranjpye RN, Strom MS. A Vibrio vulnificus type IV pilin contributes to biofilm formation, adherence to epithelial cells, and virulence. Infect Immun 2005; 73:1411-22. [PMID: 15731039 PMCID: PMC1064924 DOI: 10.1128/iai.73.3.1411-1422.2005] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus expresses a multitude of cell-associated and secreted factors that potentially contribute to pathogenicity, although the specific roles of most of these factors have been difficult to define. Previously we have shown that a mutation in pilD (originally designated vvpD), which encodes a type IV prepilin peptidase/N-methyltransferase, abolishes expression of surface pili, suggesting that they belong to the type IV class. In addition, a pilD mutant exhibits reduced adherence to HEp-2 cells, a block in secretion of several exoenzymes that follow the type II secretion pathway, and decreased virulence. In this study, we have cloned and characterized a V. vulnificus type IV pilin (PilA) that shares extensive homology to group A type IV pilins expressed by many pathogens, including Vibrio cholerae (PilA), Pseudomonas aeruginosa (PilA), and Aeromonas hydrophila (TapA). The V. vulnificus pilA gene is part of an operon and is clustered with three other pilus biogenesis genes, pilBCD. Inactivation of pilA reduces the ability of V. vulnificus to form biofilms and significantly decreases adherence to HEp-2 cells and virulence in iron dextran-treated mice. Southern blot analysis demonstrates the widespread presence of both pilA and pilD in clinical as well as environmental strains of V. vulnificus.
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Affiliation(s)
- Rohinee N Paranjpye
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric, Seattle, WA 98112, USA
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127
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Harwood VJ, Gandhi JP, Wright AC. Methods for isolation and confirmation of Vibrio vulnificus from oysters and environmental sources: a review. J Microbiol Methods 2004; 59:301-16. [PMID: 15488274 DOI: 10.1016/j.mimet.2004.08.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 06/29/2004] [Accepted: 08/06/2004] [Indexed: 12/17/2022]
Abstract
The gram-negative bacterium Vibrio vulnificus is a natural inhabitant of estuarine waters and poses a significant health threat to humans who suffer from immune disorders, liver disease, or hemochromatosis (iron overload). V. vulnificus enters human hosts via wound infections or consumption of raw shellfish (primarily oysters), and infections frequently progress to septicemia and death in susceptible individuals. Prevalence in waters and shellfish is not correlated with fecal indicator organisms; therefore, species-specific detection and enumeration of V. vulnificus in the environment has become a priority for agencies that are responsible for shellfish safety. The many selective-differential media developed for isolation of Vibrio spp., and specifically for V. vulnificus detection, are reviewed here; however, none of the media developed to date combines the sensitivity to low numbers with the specificity necessary to inhibit growth of other organisms. Therefore, immunological and molecular protocols are needed for confirmation of the identity of the organism and are discussed in detail. Methods under development that hold promise for rapid, accurate, and sensitive detection and enumeration of the organism include multiplex and real-time PCR. Developing technologies that have proven useful for detection and investigation of other pathogens such as biosensors, spectroscopy and microarrays may provide the next generation of tools for investigation of the prevalence and ecology of V. vulnificus.
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Affiliation(s)
- Valerie J Harwood
- Department of Biology, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA.
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128
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Parvathi A, Kumar HS, Karunasagar I, Karunasagar I. Detection and enumeration of Vibrio vulnificus in oysters from two estuaries along the southwest coast of India, using molecular methods. Appl Environ Microbiol 2004; 70:6909-13. [PMID: 15528563 PMCID: PMC525118 DOI: 10.1128/aem.70.11.6909-6913.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2004] [Accepted: 06/02/2004] [Indexed: 11/20/2022] Open
Abstract
This study was conducted to understand the seasonal distribution of Vibrio vulnificus in oysters from two estuaries and the effect of environmental factors on the abundance of V. vulnificus in tropical waters. V. vulnificus was detected in 56.6% of the samples tested by colony hybridization with an alkaline phosphatase-labeled oligonucleotide probe (VV-AP), and the counts ranged from <10/g during the summer months to 10(3)/g in the monsoon season at both sites. The density of V. vulnificus appeared to be controlled more by salinity than by temperature. A nested PCR used in this study detected V. vulnificus in 85% of the samples following 18 h of enrichment in alkaline peptone water.
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Affiliation(s)
- Ammini Parvathi
- Department of Microbiology, College of Fisheries, University of Agricultural Sciences, Mangalore, India
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129
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Randa MA, Polz MF, Lim E. Effects of temperature and salinity on Vibrio vulnificus population dynamics as assessed by quantitative PCR. Appl Environ Microbiol 2004; 70:5469-76. [PMID: 15345434 PMCID: PMC520858 DOI: 10.1128/aem.70.9.5469-5476.2004] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Accepted: 05/05/2004] [Indexed: 11/20/2022] Open
Abstract
The abundance of Vibrio vulnificus in coastal environments has been linked to water temperature, while its relationship to salinity is less clear. We have developed a culture-independent, most-probable-number quantitative PCR approach to examine V. vulnificus population dynamics in Barnegat Bay, N.J. Based on the combined analysis of our results from Barnegat Bay and from the literature, the present data show that (i) V. vulnificus population dynamics are strongly correlated to water temperature and (ii) although the general trend is for V. vulnificus abundance to be inversely correlated with salinity, this relationship depends on salinity levels. Irrespective of temperature, high abundances of V. vulnificus are observed at 5 to 10 ppt, which thus appears to be the optimal salinity regime for their survival. At 20 to 25 ppt, V. vulnificus abundances show a positive correlation to salinity. Unsuccessful attempts to resuscitate V. vulnificus, combined with our inability to detect cells during the winter despite an assay adapted to detect viable but nonculturable (VBNC) cells, suggest that the decline and eventual disappearance of V. vulnificus from the water column during the winter months is due primarily to a significant reduction in population size and is not only the consequence of cells entering the VBNC state. These findings are in line with the hypothesis that the sediment serves as a refuge for a subpopulation of V. vulnificus over the winter and weather-driven mixing events during the spring initiate a summer bloom in the water column.
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Affiliation(s)
- Mark A Randa
- Biology Department, Temple University, 1900 N. 12th St., Philadelphia, PA 19122, USA
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130
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Joachimsthal EL, Ivanov V, Tay STL, Tay JH. Bacteriological examination of ballast water in Singapore Harbour by flow cytometry with FISH. MARINE POLLUTION BULLETIN 2004; 49:334-343. [PMID: 15341828 DOI: 10.1016/j.marpolbul.2004.02.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this study the concentrations of total bacteria, enterobacteria, Vibrio spp., and E. coli have been compared for ballast water samples taken from ships in Singapore Harbour. The cell concentrations were enumerated using FISH and flow cytometry. The data were highly variable, reflecting the many influences upon ballast water as it is utilized in the shipping industry. The concentration of bacterial species was determined as a proportion of the total concentration of cells for the ballast water sampled. For the ballast water sampled these concentrations were 0.67-39.55% for eubacteria, 0-2.46% for enterobacteria, 0.18-35.82% for Vibrio spp., and 0-2.46% for E. coli. Using FISH and flow cytometry, an informative determination of the bacterial hazards of ship ballast water can be made.
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Affiliation(s)
- E L Joachimsthal
- Environmental Engineering Research Centre and the Maritime Research Centre, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Block N1, Singapore 639798, Singapore
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131
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Yano Y, Yokoyama M, Satomi M, Oikawa H, Chen SS. Occurrence of Vibrio vulnificus in fish and shellfish available from markets in China. J Food Prot 2004; 67:1617-23. [PMID: 15330524 DOI: 10.4315/0362-028x-67.8.1617] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vibrio vulnificus is a naturally occurring estuarine bacterium often associated with disease such as septicemia in humans following consumption of raw and lightly cooked seafood. In China and neighboring countries, rapid economic growth has encouraged increased consumption of seafood, and dietary habits are changing, with more people eating raw fish. In this study, the prevalence of V. vulnificus was investigated in 48 samples from 11 species of live seafood available from markets in coastal cities of China. The bacterium was detected in four of four razor clam samples, in seven of seven giant tiger prawn samples, and in five of nine mantis shrimp samples. The bacterium was also found in water samples of the prawn aquaria at the markets. The maximum level of V. vulnificus was 3.4 log CFU/g in the razor clam samples and 4.9 log CFU/g in the prawn samples by a direct spreading method. Differential bacterial counts on the prawn body revealed that most of the bacteria were found on the shells (exoskeletons), with very few in the edible muscle. However, dense populations can be found in the intestines. Biochemical tests indicated that the isolates of V. vulnificus were biotype 1 strain, which is pathogenic to humans. These isolates were susceptible to ampicillin, penicillin, kanamycin, streptomycin, and erythromycin. These results suggest that V. vulnificus is a potential health hazard to humans in cities consuming and handling live shellfish, especially giant tiger prawns.
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Affiliation(s)
- Yutaka Yano
- National Research Institute of Fisheries Science, Yokohama 2368648, Japan.
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132
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Thompson JR, Randa MA, Marcelino LA, Tomita-Mitchell A, Lim E, Polz MF. Diversity and dynamics of a north atlantic coastal Vibrio community. Appl Environ Microbiol 2004; 70:4103-10. [PMID: 15240289 PMCID: PMC444776 DOI: 10.1128/aem.70.7.4103-4110.2004] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2003] [Accepted: 03/24/2004] [Indexed: 11/20/2022] Open
Abstract
Vibrios are ubiquitous marine bacteria that have long served as models for heterotrophic processes and have received renewed attention because of the discovery of increasing numbers of facultatively pathogenic strains. Because the occurrence of specific vibrios has frequently been linked to the temperature, salinity, and nutrient status of water, we hypothesized that seasonal changes in coastal water bodies lead to distinct vibrio communities and sought to characterize their level of differentiation. A novel technique was used to quantify shifts in 16S rRNA gene abundance in samples from Barnegat Bay, N.J., collected over a 15-month period. Quantitative PCR (QPCR) with primers specific for the genus Vibrio was combined with separation and quantification of amplicons by constant denaturant capillary electrophoresis (CDCE). Vibrio populations identified by QPCR-CDCE varied between summer and winter samples, suggesting distinct warm-water and year-round populations. Identification of the CDCE populations by cloning and sequencing of 16S rRNA genes from two summer and two winter samples confirmed this distinction. It further showed that CDCE populations corresponded in most cases to approximately 98% rRNA similarity groups and suggested that the abundance of these follows temperature trends. Phylogenetic comparison yielded closely related cultured and often pathogenic representatives for most sequences, and the temperature ranges of these isolates confirmed the trends seen in the environmental samples. Overall, this suggests that temperature is a good predictor of the occurrence of closely related vibrios but that considerable microdiversity of unknown significance coexists within this trend.
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Affiliation(s)
- Janelle R Thompson
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 48-421, 77 Massachusetts Ave., Cambridge, MA 02139, USA
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133
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Abstract
Vibrio vulnificus is an opportunistic human pathogen commonly found in estuarine environments. Infections are associated with raw oyster consumption and can produce rapidly fatal septicemia in susceptible individuals. Standard enumeration of this organism in shellfish or seawater is laborious and inaccurate; therefore, more efficient assays are needed. An oligonucleotide probe derived from the cytolysin gene, vvhA, was previously used for colony hybridizations to enumerate V. vulnificus. However, this method requires overnight growth, and vibrios may lack culturability under certain conditions. In the present study, we targeted the same locus for development of a TaqMan real-time PCR assay. Probe specificity was confirmed by amplification of 28 V. vulnificus templates and by the lack of a PCR product with 22 non-V. vulnificus strains. Detection of V. vulnificus in pure cultures was observed over a 6-log-unit linear range of concentration (10(2) to 10(8) CFU ml(-1)), with a lower limit of 72 fg of genomic DNA micro l of PCR mixture(-1) or the equivalent of six cells. Similar sensitivity was observed in DNA extracted from mixtures of V. vulnificus and V. parahaemolyticus cells. Real-time PCR enumeration of artificially inoculated oyster homogenates correlated well with colony hybridization counts (r(2) = 0.97). Numbers of indigenous V. vulnificus cells in oysters by real-time PCR showed no significant differences from numbers from plate counts with probe (t test; P = 0.43). Viable but nonculturable cells were also enumerated by real-time PCR and confirmed by the BacLight viability assay. These data indicate that real-time PCR can provide sensitive species-specific detection and enumeration of V. vulnificus in seafood.
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134
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Butt AA, Aldridge KE, Sanders CV. Infections related to the ingestion of seafood Part I: viral and bacterial infections. THE LANCET. INFECTIOUS DISEASES 2004; 4:201-12. [PMID: 15050937 DOI: 10.1016/s1473-3099(04)00969-7] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Foodborne diseases cause an estimated 76 million illnesses in the USA each year. Seafood is implicated in 10-19% of these illnesses. A causative agent can be traced in about 44% of seafood-related outbreaks, viruses accounting for around half of these illnesses. Although viruses are the most common cause of seafood-related infections, most hospitalisations and deaths are due to bacterial agents. A wide variety of viruses, bacteria, and parasites have been implicated in seafood-related outbreaks, which are reported worldwide. The factor most commonly associated with infection is consumption of raw or undercooked seafood. People with underlying disorders, particularly liver disease, are more susceptible to infection. The first part of this two-part review summarises the general incidence of seafood-related infections and discusses the common viral and bacterial causes of these infections. For each agent, the microbiology, epidemiology, mode of transmission, and treatment are discussed. In the May issue of the journal we will discuss parasites associated with seafood consumption, the safety of seafood, and the measures put in place in the USA to increase its safety.
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Affiliation(s)
- Adeel A Butt
- Division of Infectious Diseases, University of Pittsburgh, the VA Pittsburgh Healthcare System, and the Center for Health Equity Research and Promotion, Pittsburgh, PA 15213, USA.
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135
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Joseph LA, Wright AC. Expression of Vibrio vulnificus capsular polysaccharide inhibits biofilm formation. J Bacteriol 2004; 186:889-93. [PMID: 14729720 PMCID: PMC321485 DOI: 10.1128/jb.186.3.889-893.2004] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is a human pathogen that produces lethal septicemia in susceptible persons, and the primary virulence factor for this organism is capsular polysaccharide (CPS). The role of the capsule in V. vulnificus biofilms was examined under a variety of conditions, by using either defined CPS mutants or spontaneous CPS expression phase variants derived from multiple strains. CPS expression was shown to inhibit attachment and biofilm formation, which contrasted with other studies describing polysaccharides as integral to biofilms in related species.
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Affiliation(s)
- Lavin A Joseph
- Aquatic Food Products Laboratory, Food Science and Human Nutrition Department, University of Florida, Gainesville, Florida 32611, USA
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136
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Morris JG. Cholera and other types of vibriosis: a story of human pandemics and oysters on the half shell. Clin Infect Dis 2003; 37:272-80. [PMID: 12856219 DOI: 10.1086/375600] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2003] [Accepted: 03/17/2003] [Indexed: 11/03/2022] Open
Abstract
Vibrios are ubiquitous in the aquatic environment and are commonly present in or on shellfish and other seafood. A small subset of strains/species are able to cause human disease, including the cholera toxin-producing strains of Vibrio cholerae that are responsible for epidemic/pandemic cholera; thermostable direct hemolysin-producing strains of Vibrio parahaemolyticus; and Vibrio vulnificus, which can cause fulminant sepsis. Cholera outbreaks can be initiated by transmission of "epidemic" V. cholerae strains from their environmental reservoir to humans through seafood or other environmentally related food or water sources. "Nonepidemic" strains of V. cholerae and strains of other Vibrio species, including V. parahaemolyticus and V. vulnificus, are generally acquired by eating seafood (particularly raw oysters/oysters on the half shell). Although the primary clinical manifestation of infection with these strains is gastroenteritis, they can also cause wound infections and (particularly for V. vulnificus) septicemia in persons who have liver disease or are immunocompromised.
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Affiliation(s)
- J Glenn Morris
- Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, and Baltimore Veterans Affairs Medical Center, 21201, USA.
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137
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Lin M, Payne DA, Schwarz JR. Intraspecific diversity of Vibrio vulnificus in Galveston Bay water and oysters as determined by randomly amplified polymorphic DNA PCR. Appl Environ Microbiol 2003; 69:3170-5. [PMID: 12788713 PMCID: PMC161529 DOI: 10.1128/aem.69.6.3170-3175.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2002] [Accepted: 03/24/2003] [Indexed: 11/20/2022] Open
Abstract
Randomly amplified polymorphic DNA (RAPD) PCR was used to analyze the temporal and spatial intraspecific diversity of 208 Vibrio vulnificus strains isolated from Galveston Bay water and oysters at five different sites between June 2000 and June 2001. V. vulnificus was not detected during the winter months (December through February). The densities of V. vulnificus in water and oysters were positively correlated with water temperature. Cluster analysis of RAPD PCR profiles of the 208 V. vulnificus isolates revealed a high level of intraspecific diversity among the strains. No correlation was found between the intraspecific diversity among the isolates and sampling site or source of isolation. After not being detected during the winter months, the genetic diversity of V. vulnificus strains first isolated in March was 0.9167. Beginning in April, a higher level of intraspecific diversity (0.9933) and a major shift in population structure were observed among V. vulnificus isolates. These results suggest that a great genetic diversity of V. vulnificus strains exists in Galveston Bay water and oysters and that the population structure of this species is linked to changes in environmental conditions, especially temperature.
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Affiliation(s)
- Meilan Lin
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas 77551, USA
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138
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Stin OC, Carnahan A, Singh R, Powell J, Furuno JP, Dorsey A, Silbergeld E, Williams HN, Morris JG. Characterization of microbial communities from coastal waters using microarrays. ENVIRONMENTAL MONITORING AND ASSESSMENT 2003; 81:327-336. [PMID: 12620025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the "health" of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.
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Affiliation(s)
- O Colin Stin
- Department of Epidemiology and Preventive Medicine, School of Medicine, University of Maryland Baltimore, Baltimore, Maryland, USA.
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139
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Romero J, Gonzalez N, Espejo R. Marine Pseudoalteromonas sp. Composes Most of the Bacterial Population Developed in Oysters (Tiostrea chilensis) Spoiled During Storage. J Food Sci 2002. [DOI: 10.1111/j.1365-2621.2002.tb09544.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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140
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Gooch JA, DePaola A, Bowers J, Marshall DL. Growth and survival of Vibrio parahaemolyticus in postharvest American oysters. J Food Prot 2002; 65:970-4. [PMID: 12092730 DOI: 10.4315/0362-028x-65.6.970] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oysters at the retail stage of distribution generally contain greater densities of Vibrio parahaemolyticus than do oysters at harvest. The objective of this study was to determine the effects of postharvest storage at 26 and 3 degrees C on the growth and survival of naturally occurring V. parahaemolyticus in shellstock American oysters (Crassostrea virginica). Oysters were collected monthly from May 1998 through April 1999 from Mobile Bay, Alabama, and their V. parahaemolyticus densities were determined after 0, 5, 10, and 24 h of postharvest storage at 26 degrees C. After 24 h of storage at 26 degrees C, oysters were transferred to a refrigerator at 3 degrees C and analyzed 14 to 17 days later. V. parahaemolyticus numbers were determined by a direct plating method involving an alkaline-phosphatase-labeled DNA probe that targets the species-specific thermolabile hemolysin gene (tlh-AP) to identify suspect isolates. From April to December, when water temperatures at harvest were >20 degrees C, the geometric mean harvest density of V. parahaemolyticus was 130 CFU/g. When water temperatures were <20 degrees C, the geometric mean harvest density was 15 CFU/g. After harvest, V. parahaemolyticus multiplied rapidly in live oysters held at 26 degrees C, showing a 50-fold increase (1.7 log CFU/g) at 10 h and a 790-fold increase (2.9 log CFU/g) at 24 h (April through December). Average V. parahaemolyticus numbers showed a sixfold decrease (0.8 log CFU/g) after approximately 14 days of refrigeration. These results indicate that V. parahaemolyticus can grow rapidly in unrefrigerated oysters.
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Affiliation(s)
- J A Gooch
- U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina 29412-9110, USA.
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141
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Tanaka R, Sawabe T, Yoshimizu M, Ezura Y. Distribution of Vibrio halioticoli around an Abalone-farming Center in Japan. Microbes Environ 2002. [DOI: 10.1264/jsme2.2002.6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Reiji Tanaka
- Laboratory of Microbiology, Graduate School of Fisheries Sciences, Hokkaido University
| | - Tomoo Sawabe
- Laboratory of Microbiology, Graduate School of Fisheries Sciences, Hokkaido University
| | - Mamoru Yoshimizu
- Laboratory of Microbiology, Graduate School of Fisheries Sciences, Hokkaido University
| | - Yoshio Ezura
- Laboratory of Microbiology, Graduate School of Fisheries Sciences, Hokkaido University
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142
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Lorca TA, Pierson MD, Flick GJ, Hackney CR. Levels of Vibrio vulnificus and organoleptic quality of raw shellstock oysters (Crassostrea virginica) maintained at different storage temperatures. J Food Prot 2001; 64:1716-21. [PMID: 11726149 DOI: 10.4315/0362-028x-64.11.1716] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Temperature abuse during raw oyster harvesting and storage may allow for the multiplication of natural spoilage flora as well as microbial pathogens, thus posing a potential health threat to susceptible consumers and compromising product quality. The objective of this study was to provide a scientific basis for determining whether different refrigeration and abuse temperatures for raw oysters would result in a spoiled product before it became unsafe. Raw shellstock oysters (Crassostrea virginica) purchased from a commercial Virginia processor were subjected to different temperature abuse conditions (7, 13, and 21 degrees C) over a 10-day storage period. Salinity, pH, halophilic plate count (HPC), total culturable Vibrio counts, and culturable Vibrio vulnificus counts were determined at each abuse condition. V. vulnificus isolates were confirmed by a specific enzyme-linked immunosorbent assay. Olfactory analysis was performed to determine consumer acceptability of the oysters at each abuse stage. The pH of the oysters decreased over time in each storage condition. The HPC increased 2 to 4 logs for all storage conditions, while olfactory acceptance decreased over time. V. vulnificus levels increased over time, reaching 10(5) to 10(6) CFU/g by day 6. The length of storage had a greater effect on the bacterial counts and olfactory acceptance of the oysters (P < 0.05) over time than did the storage temperature (P < 0.05).
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Affiliation(s)
- T A Lorca
- Department of Food Science and Technology, Virginia Tech, Blacksburg 24061-0418, USA
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143
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Wright AC, Powell JL, Kaper JB, Morris JG. Identification of a group 1-like capsular polysaccharide operon for Vibrio vulnificus. Infect Immun 2001; 69:6893-901. [PMID: 11598064 PMCID: PMC100069 DOI: 10.1128/iai.69.11.6893-6901.2001] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Virulence of Vibrio vulnificus correlates with changes in colony morphology that are indicative of a reversible phase variation for expression of capsular polysaccharide (CPS). Encapsulated variants are virulent with opaque colonies, whereas phase variants with reduced CPS expression are attenuated and are translucent. Using TnphoA mutagenesis, we identified a V. vulnificus CPS locus, which included an upstream ops element, a wza gene (wza(Vv)), and several open reading frames with homology to CPS biosynthetic genes. This genetic organization is characteristic of group 1 CPS operons. The wza gene product is required for transport of CPS to the cell surface in Escherichia coli. Polar transposon mutations in wza(Vv) eliminated expression of downstream biosynthetic genes, confirming operon structure. On the other hand, nonpolar inactivation of wza(Vv) was specific for CPS transport, did not alter CPS biosynthesis, and could be complemented in trans. Southern analysis of CPS phase variants revealed deletions or rearrangements at this locus. A survey of environmental isolates indicated a correlation between deletions in wza(Vv) and loss of virulent phenotype, suggesting a genetic mechanism for CPS phase variation. Full virulence in mice required surface expression of CPS and supported the essential role of capsule in the pathogenesis of V. vulnificus.
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Affiliation(s)
- A C Wright
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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144
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Cerdà-Cuéllar M, Permin L, Larsen JL, Blanch AR. Comparison of selective media for the detection of Vibrio vulnificus in environmental samples. J Appl Microbiol 2001; 91:322-7. [PMID: 11473597 DOI: 10.1046/j.1365-2672.2001.01387.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS To compare two selective agars, cellobiose-colistin (CC) agar and a modification of the Vibrio vulnificus medium (VVMc agar), for the isolation of Vibrio vulnificus from environmental samples. METHODS AND RESULTS The efficiencies of recovery of V. vulnificus collection strains on CC, VVM, VVMc and on thiosulphate-citrate-bile salts-sucrose (TCBS) agar were compared and similar efficiencies were obtained. A slightly higher recovery was observed on VVMc agar. The detection of V. vulnificus in environmental samples (eels and water) was performed by combining culture-based methods (CC and VVMc agars) with DNA-based methods using species-specific probes based on the cytolysin-haemolysin and the 16S rDNA genes. A lower accompanying microbiota was found on CC agar than on VVMc agar. CONCLUSION The comparison between CC and VVMc agars confirms that both are useful for the detection of V. vulnificus in environmental samples. However, the use of any of these media should be combined with a species-specific probe. SIGNIFICANCE AND IMPACT OF THE STUDY The combined use of a selective medium and a specific probe provides a feasible method for the detection of V. vulnificus for epidemiological and ecological studies.
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Affiliation(s)
- M Cerdà-Cuéllar
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
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145
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Sizemore J, Mitre E. Leg pain in a patient with chronic hepatitis C. Lancet 2001; 357:440. [PMID: 11273065 DOI: 10.1016/s0140-6736(00)04009-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J Sizemore
- Johns Hopkins Hospital, Baltimore, MD, USA
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146
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GRIFFIN DALEW, LIPP ERINK, McLAUGHLIN MOLLYR, ROSE JOANB. Marine Recreation and Public Health Microbiology: Quest for the Ideal Indicator. Bioscience 2001. [DOI: 10.1641/0006-3568(2001)051[0817:mraphm]2.0.co;2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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147
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McCarthy SA, DePaola A, Kaysner CA, Hill WE, Cook DW. Evaluation of nonisotopic DNA hybridization methods for detection of the tdh gene of vibrio parahaemolyticus. J Food Prot 2000; 63:1660-4. [PMID: 11131887 DOI: 10.4315/0362-028x-63.12.1660] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Production of the thermostable direct hemolysin (TDH) by Vibrio parahaemolyticus is associated with pathogenicity of the organism and is encoded by the tdh gene. The timely resolution of seafood-associated outbreaks requires rapid and accurate detection of pathogenic V. parahaemolyticus. The specificity of alkaline phosphatase- and digoxigenin-labeled tdh gene probes was evaluated against 61 strains of V. parahaemolyticus (including isolates from recent outbreaks involving oysters from the Pacific Northwest, Texas, and New York), 85 strains of other vibrios, and 7 strains of non-vibrio species from clinical and environmental sources. The probes were specific for detection of the V. parahaemolyticus tdh gene.
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Affiliation(s)
- S A McCarthy
- Gulf Coast Seafood Laboratory, US Food and Drug Administration, Dauphin Island, Alabama 36528, USA.
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148
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Abstract
Pathogenic bacteria, when present in marine seafood and in fresh cultured products, are usually found at fairly low levels, and where these products are adequately cooked, food safety hazards are insignificant. A few bacteria associated with faecal contamination of seafood continue to pose a large-scale health threat through seafood.
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Affiliation(s)
- F Feldhusen
- State Veterinary Institute for Fish and Fishery Products, Schleusenstr., D-27472, Cuxhaven, Germany.
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149
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Lee SE, Shin SH, Kim SY, Kim YR, Shin DH, Chung SS, Lee ZH, Lee JY, Jeong KC, Choi SH, Rhee JH. Vibrio vulnificus has the transmembrane transcription activator ToxRS stimulating the expression of the hemolysin gene vvhA. J Bacteriol 2000; 182:3405-15. [PMID: 10852871 PMCID: PMC101907 DOI: 10.1128/jb.182.12.3405-3415.2000] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In an attempt to dissect the virulence regulatory mechanism in Vibrio vulnificus, we tried to identify the V. cholerae transmembrane virulence regulator toxRS (toxRS(Vc)) homologs in V. vulnificus. By comparing the sequences of toxRS of V. cholerae and V. parahaemolyticus (toxRS(Vp)), we designed a degenerate primer set targeting well-conserved sequences. Using the PCR product as an authentic probe for Southern blot hybridization, a 1.6-kb BglII-HindIII fragment and a 1.2-kb HindIII fragment containing two complete open reading frames and one partial open reading frame attributable to toxR(Vv), toxS(Vv), and htpG(Vv) were cloned. ToxR(Vv) shared 55.0 and 63.0% sequence homology with ToxR(Vc) and ToxR(Vp), respectively. ToxS(Vv) was 71.5 and 65.7% homologous to ToxS(Vc) and ToxS(Vp), respectively. The amino acid sequences of ToxRS(Vv) showed transmembrane and activity domains similar to those observed in ToxRS(Vc) and ToxRS(Vp). Western blot analysis proved the expression of ToxR(Vv) in V. vulnificus. ToxRS(Vv) enhanced, in an Escherichia coli background, the expression of the V. vulnificus hemolysin gene (vvhA) fivefold. ToxRS(Vv) also activated the ToxR(Vc)-regulated ctx promoter incorporated into an E. coli chromosome. A toxR(Vv) null mutation decreased hemolysin production. The defect in hemolysin production could be complemented by a plasmid harboring the wild-type gene. The toxR(Vv) mutation also showed a reversed outer membrane protein expression profile in comparison to the isogenic wild-type strain. These results demonstrate that ToxR(Vv) may regulate the virulence expression of V. vulnificus.
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Affiliation(s)
- S E Lee
- Department of Microbiology, Chosun University Medical School, Kwangju, Republic of Korea
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150
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Cerdà-Cuéllar M, Jofre J, Blanch AR. A selective medium and a specific probe for detection of Vibrio vulnificus. Appl Environ Microbiol 2000; 66:855-9. [PMID: 10653765 PMCID: PMC91910 DOI: 10.1128/aem.66.2.855-859.2000] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/1999] [Accepted: 12/06/1999] [Indexed: 01/22/2023] Open
Abstract
A selective medium (VVM) and a specific 16S rRNA gene (rDNA) probe (V3VV) for the detection of Vibrio vulnificus were developed. The medium contains D-(+)-cellobiose as the main carbon source and electrolytes (MgCl(2)-6H(2)O and KCl), which stimulate bacterial growth. Polymyxin B, colistin, and moderate alkalinity and salinity provide selectivity properties. V. vulnificus grows on VVM as flat, bright yellow colonies. Other Vibrio species tested either did not grow or showed green-bluish colonies, with the exception of V. campbelli, V. carchariae, and V. navarrensis. There is a higher colony count on VVM agar than on cellobiose-colistin agar or on modified cellobiose-polymyxin B-colistin agar. The specific probe was evaluated by colony hybridization and dot blot hybridization with PCR-amplified 16S rDNA using collection strains and environmental isolates. No strain studied other than V. vulnificus showed positive hybridization with this oligonucleotide. The combined use of VVM agar and the V3VV probe provided the recovery of V. vulnificus from mixed bacterial suspensions and spiked mussels.
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Affiliation(s)
- M Cerdà-Cuéllar
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain.
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