• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.555-559
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• 2013

Vibrio cholerae O1 and O139 are the major serotypes associated with illness, and some V. cholera non-O1 and non-O139 isolates produce cholera toxin. The present study describes a quantitative polymerase chain reaction (qPCR) assay for the species-specific detection and quantitation of V. cholera using a primer pair based on an outer membrane lipoprotein lolB gene for the amplification of a 195 bp DNA fragment. The qPCR primer set for the accurate diagnosis of V. cholera was developed from publically available genome sequences. This quantitative PCR-based method will potentially simplify and facilitate the diagnosis of this pathogen and guide disease management.

• 한국미생물·생명공학회지
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• 제31권4호
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• pp.334-341
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• 2003

2001년 경북지역 콜레라 유행시 설사환자에서 V. cholerae O1 El Tor형 90주를 분리하였다. 분리균을 대상으로 ctxA, tcpA, hlyA gene에 대한 multiplex-PCR 시험에서는 분리균 모두에서 302, 223, 471 bps크기의 DNA 증폭산물 band를 확인하였다. ctxA 및 ctxB gene 부위의 유전자 염기서열 비교에서 분리균과 GenBank에 수록된 균간의 유형의 차이를 보였다. PFGE typing 실험에서는 분리균 모두에서 동일한 amplicon 단편을 나타내었다. 또한, 2002년 8월부터 10월까지 콜레라균 서식가능성 규명을 위해 경북 동해안 일대에서 plankton 시료채취 및 V. cholerae O1 및 V. cholerae O139의 rfb 및 CT gene 검출을 위한 multiplex-PCR 확인실험에서는 ctxA gene의 DNA band는 일부 검출되었으나, V. cholerae O1 및 V. cholerae O139는 분리되지 않았다. 험에서 ctxA gene DNA band는 검출되었으나, V. cholerae O1 및 V. cholerae O1는 분리되지 않았다.

• 환경위생공학
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• 제2권2호
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• pp.61-67
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• 1987

The genus Vibrio contains some of the most important intestinal pathogens of humans, including Vibrio cholerae, the cause of epidemic Asiatic cholera. A group of organisms which have been reffered to as the non-agglutinating vibrio (NAG) do not agglutinate in the Vibrio cholerae 0 group 1 antisera, but are indistinguishable from the 0-1 group both chemically and genetically. Non-O-l Vibrio cholerae can cause isolated as well as focal outbreaks of diarrhea, but the volume of fluid loss does not approach that of classic cholera, and the disease is usually self-limiting. These free-living organisms are found world-widely distributed in the environment including sewage, contaminated water, estuaries, seafood and animals. These strains involved in several cases were isolated from the environment and some patients of diarrhea, and a few epidemiologic reports indicated the wide distribution of the strains throughout the country, giving an attention to the role the organisms may play in an outbreak of diarrhea in Korea. More research on the epidemiology, serologic typing and virulence of the group of organisms, should be, therefore, done to obtain a complete understanding of their role in human disease.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1396-1405
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• 2022

Cholera remains a major global public health problem, for which oral cholera vaccines (OCVs) being a valuable strategy. Patients, who have recovered from cholera, develop antibody responses against LPS, cholera toxin (CT), toxin-coregulated pilus (TCP) major subunit A (TcpA) and other antigens; thus, these responses are potentially important contributors to immunity against Vibrio cholerae infection. However, assessments of the efficacy of current OCVs, especially inactivated OCVs, have focused primarily on O-antigen-specific antibody responses, suggesting that more sophisticated strategies are required for inactivated OCVs to induce immune responses against TCP, CT, and other antigens. Previously, we have shown that the toxT-139F allele enables V. cholerae strains to produce CT and TCP under simple laboratory culture conditions. Thus, we hypothesized that V. cholerae strains that express TCP via the toxT-139F allele induce TCP-specific antibody responses. As anticipated, V. cholerae strains that expressed TCP through the toxT-139F allele elicited antibody responses against TCP when the inactivated bacteria were delivered via a mouse model. We have further developed TCP-expressing V. cholerae strains that have been used in inactivated OCVs and shown that they effect an antibody response against TcpA in vivo, suggesting that V. cholerae strains with the toxT-139F allele are excellent candidates for cholera vaccines.

• 약학회지
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• 제17권1호
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• pp.17-20
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• 1973

Six novel compounds of N,N-dimethyl-N'-(6-substituted-2-benzothiazolyl) formamidines nad six novel compounds of N, N-dimethyl-N'-(substituted-phenyl)formamidines were synthesized. They were evaluated fro their bactericidal activities aginst Salmonella typhoso, Escherichia coli, Vibrio cholera, Staphyloccus aureus, Sarcina lutea and for their fungicidal activities against Saccharomyces cereviseae, Candida albicans. It was found that these compounds were considerably more active than phenol, especially against Vibrio cholera, and N, N-dimethy-N'-(4-methyl-phenyl_formamkidine, N, N-dimethyl-N'-(2-methyl-4-bromo-phenyl)formanidine showed most potent bactericidal activities.

• 한국환경보건학회지
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• 제44권2호
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• pp.133-142
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• 2018

Objectives: The pathogenic Vibrios genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus are the most important species since they can be potent human pathogens and leading causes of septicemia, wound infections, and seafood borne gastroenteritis. The recent emergence of a potential pandemic clone, V. cholera serotype O1 and the cholera outbreak in South Korea in 2016 indicates the importance of consistent surveillance of pathogenic Vibrio genus within coastal areas. Methods: The present study was undertaken to determine where and how vibrios live in the aquatic environment adjacent to coastal areas of South Korea. For this survey, a total of 838 samples were obtained at 35 different sites in South Korean coastal areas during the period from January 2016 to December 2016. Pathogenic vibrios was determined using the real-time PCR method, and its clones were isolated using three selective plating media. We also monitored changes in seawater and atmospheric temperature, salinity, turbidity, and hydrogen ion concentration at the collection points. Results: The total isolation rates of V. vulnificus, V. cholera (non-pathogenic, non-O1, non-O139 serogroups), and V. parahaemolyticus from seawater specimens in 2016 were 14.2, 13.48, and 67.06%, respectively. Conclusions: The isolation rates of pathogenic vibrios genus showed a positive correlation with temperature of seawater and atmosphere but were negatively correlated with salinity and turbidity.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.725-731
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• 2014

The classical biotype strains of the Vibrio cholerae O1 serogroup harbor the biotype-specific cholera-toxin encoding phage (CTX) $CTX^{cla}$, and the El Tor biotype strains contain CTX-1. Although the classical biotype strains have become extinct, a remnant of classical CTX phage is transferred to the El Tor biotype strains. The prototype El Tor strains, which produce the biotype-specific cholera toxin, are now being replaced by atypical El Tor variant strains producing classical biotype cholera toxin. The genome sequences of the CTX phages in atypical El Tor strains indicate that the CTX phages in atypical El Tor strains are a mosaic of $CTX^{cla}$ and CTX-1. Before the emergence of atypical El Tor stains in the early 1990s, unusual pre-seventh pandemic strains were isolated in the US Gulf Coast between 1973 and 1986. These strains have characteristics of atypical El Tor strains since they are El Tor biotype strains containing $CTX^{cla}$, yet the genome sequence of this CTX phage indicates that it is different from $CTX^{cla}$ and is therefore classified separately as $CTX^{US\;Gulf}$.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.736-744
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• 2023

The introduction of the toxT-139F allele triggers the expression of TCP (toxin co-regulated pilus) and CT (cholera toxin) under simple laboratory culture conditions in most Vibrio cholerae strains. Such V. cholerae strains, especially strains that have been used in OCVs (oral cholera vaccines), can induce antibody responses against TCP in animal models. However, CT produced in these V. cholerae strains is secreted into the culture medium. In this study, V. cholerae strains that can express intracellular CTB under the control of the toxT-139F allele have been constructed for potential application in OCVs. First, we constructed a recombinant plasmid directly linking the ctxAB promoter to ctxB without ctxA and confirmed CTB expression from the plasmid in V. cholerae containing the toxT-139F allele. We constructed another recombinant plasmid to express NtrCTB, from which 14 internal amino acids-from the 7^th to the 20^th amino acid-of the leader peptide of CTB have been omitted, and we found that NtrCTB remained in the cells. Based on those results, we constructed V. cholerae strains in which chromosomal ctxAB is replaced by ntrctxB or ntrctxB-dimer. Both NtrCTB and NtrCTB-dimer remained in the bacterial cells, and 60% of the NtrCTB-dimer in the bacterial cells was maintained in a soluble form. To develop improved OCVs, these strains could be tested to see whether they induce immune responses against CTB in animal models.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.627-636
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• 2016

The causative agent of pandemic cholera, Vibrio cholerae, infects the anaerobic environment of the human intestine. Production of cholera toxin (CT), a major virulence factor of V. cholerae, is highly induced during anaerobic respiration with trimethylamine N-oxide (TMAO) as an alternative electron acceptor. However, the molecular mechanism of TMAO-stimulated CT production is not fully understood. Herein, we reveal that CT production during anaerobic TMAO respiration is affected by glucose fermentation. When the seventh pandemic V. cholerae O1 strain N16961 was grown with TMAO and additional glucose, CT production was markedly reduced. Furthermore, an N16961 Δcrp mutant, devoid of cyclic AMP receptor protein (CRP), was defective in CT production during growth by anaerobic TMAO respiration, further suggesting a role of glucose metabolism in regulating TMAO-mediated CT production. TMAO reductase activity was noticeably decreased when grown together with glucose or by mutation of the crp gene. A CRP binding region was identified in the promoter region of the torD gene, which encodes a structural subunit of the TMAO reductase. Gel shift assays further confirmed the binding of purified CRP to the torD promoter sequence. Together, our results suggest that the bacterial ability to respire using TMAO is controlled by CRP, whose activity is dependent on glucose availability. Our results reveal a novel mechanism for the regulation of major virulence factor production by V. cholerae under anaerobic growth conditions.