Background: Only strains of V cholerae 01 that produce cholera toxin have been associated with epidemics and pandemics in the past; therefore, production of cholera toxin has become an important marker for identifying isolates with the potential to cause epidemics. The Reversed Passive Latex Agglutination test (RPLA) is a semi-quantitative determination of CT or LT in culture fluid. \r\n', u'Objective: To determine the cholera toxin by RPLA in order to evaluate the severity of the epidemic and find an interventional solution.\r\n', u'Subjects and methods: The technique of RPLA enables soluble antigen such as bacterial toxins to be detected in an agglutination assay. A total of 44 strains of V. cholerae 01 were tested for the production of the cholera toxin by RPLA.\r\n', u' Results and conclusion: The concentration of cholera toxin was determined from strains isolated in 2007 much higher than that from the strains isolated in 2004. These results can explain the severe cholera endemic in 2007 in comparison with the endemic in 2004. The RPLA test is a simple and reliable method for determining cholera toxin and suitable for epidemiologic studies on cholera. \r\n', u'
Reversed passive latex agglutination ; cholera toxin

200 strains of E.Coli collected from diarrhoea patients at Bach Mai, Dong Da and Dong Anh Hospitals in Ha Noi, were investigated. By mutiplex PCR, the gene of various toxicities of 5 pathogene E. Coli strains were identified. This diagnostic technique has got epidemiological value helping physicians to perform concurrently a large number of samples, saving the time and the materials.
Polymerase Chain Reaction ; Diagnosis ; Escherichia coli

24 volunteers were divided into 3 groups. Group 1 of 10 subjects was given vaccine in addition of bicarbonate damper, group 2 of 9 subjects was given vaccine and water, group 3 of 5 subjects was given bicarbonate damper. Anti LPS antibody value of V. cholerae 01 of IgA class in ELISA spot was higher significantly than serum ELISA in same time point. Lymphocyte producing IgA antibody persisted about 5 months after immunization. IgM antibody excreting cells had activated promptly rather just 7 days after the first time of talking oral vaccine with a mean value 8 times higher than the mean value before taking vaccine. 100% of studied subjects in 2 groups had had the response of IgA antibody excreted through peripheral blood lymphocytes.
Cholera Vaccines ; Lymphocytes ; Technical Report [Publication Type]

Study the rapid serodiagnosis of typhoid fever in 41 samples collected at Saint Paul Hospital, Traffic-Transport Hospital, centers of preventive medicine in Hanoi, Lai Chau, Thai Binh from 2002 December to 2003 June. Results: IgM(+) and IgG(+) in 29 samples, IgM(-) and IgG(+) in 8 samples, IgM(-) and IgG(-) in 3 samples, and 1 unspecified sample. Most of typhoid patients eliminated bacteria in feces 4-12 weeks after recovery. Few patients continued elimination after 12 weeks. Typhi-Dot technique overcomes disadvantages of Widal reaction, gives quick result within 1 hour, has high sensitivity and specificity, simple technique, not requires expensive equipments, and could test many samples at the same time
Typhoid Fever ; Serologic Tests ; Diseases

The study carries on 87 E.coli strains. Using reversed passive latex agglutination (RPLA) technique to discover factor causing disease EspB to confirm EPEC. The result: 27 strains have no gene eae, 52 strains has eae possitive, 19 of them has Stx. In fact, following traditional, the rate infected EPEC was determined essentialy relying on slide agglutination reaction with antiserum group O of EPEC. This experience showed that the factor causing disease EspB in order to determine EPEC can apply at clinical laboratory or in community, although, most ETEC extract also EspB, Sxt and can also be determined in similar culture. This method is necessary need and significance in fact
Escherichia coli ; diagnosis ; Agglutination

4 strains of Vibrio cholerae 01 E1 Tor (V.cholerae 01) isolated from patients of various areas in Vietnam (20 strains in the year 1995 and 24 in 2000) and 256 strains of V.cholerae 01 isolated from various areas in Laos. (15 strains in 1993-1994 period, 21 in 1995-1996, 91 in 1998, 16 in 1999 and 109 in 2000). The ones from Laos in 1993-1996 years period were sensitive to common antibiotics such as tetracyclin, chloramphenicol, trimethoprim, but the ones of 1998-2000 were resistant to these antibiotics. The strains of V.cholerae 01 isolated in Vietnam in the year 1995 were sensitive to tetracyclin and chloramphenicol, but the ones in the year 2000 were resistant with a medium level. The strains of V.cholerae 01 in Vietnam were resistant to polymycin B, but the ones in Laos were sensitive to polymycin B
Vibrio cholerae ; Pharmaceutical Preparations ; epidemiology ; drugs

The random amplified polymorphic DNA (RAPD) technique was used to distinguish 60 strains of Vibrio cholerae 01 E1 Tor isolated from patients in 1991-2002 period. There were 6 strains isolated from HoChiMinh city, 43 strains from Nha Trang, 8 strains from Hanoi and 3 strains from Tay Nguyen Highland. In RAPD technique, DNA oligomers with 10 nucleotids was selected randomly using to synthese prime DNA from the sites of properly paired aminoacids. Strain specific amplified DNA was created. AP42 and AP46 were used to identify the gene of various strains in diverse areas. Results of RAPD showed that these strains of bacteria had a same origin. RAPD technique can be used to supervise the transmission of bacteria in human
DNA ; Random Amplified Polymorphic DNA Technique ; Vibrio cholerae ; DNA Fingerprinting

A total of 200 pathogenic strains of Escherichia coli collected on diarrhoea patients at the hospital BachMai, DongDa and DongAnh in Hanoi were studied.By multiplex PCR assay, genes of various toxicity levels were determined on 5 pathogenic E coli: 2 EPEC, 5 ETEC , 8 EAEC. There were 15 strains in which, pathogenic genes of E.coli causing diarrhoea which accounted for 7,5%.In comparing the multiplex PCR technique and simplex PCR technique, results were the same
Escherichia coli ; Diagnosis ; Polymerase Chain Reaction

Background: Food-born bacteria can be present in raw materials or contaminated foods during process and storage. Shrimp paste is a popular food in Viet Nam, but there are no studies on the hygiene and safety of this food. Objectives: To identify the microbial contamination of commercial shrimp paste available in Ha Noi City. Materials and method: A total of 50 shrimp paste samples were collected randomly from markets around Ha Noi City. Enumeration and isolation methods were used to determine the microbial contamination in these samples. Results: 100% of the samples were contaminated with Clostridium perfringens and Candida albicans. 10% of samples were contaminated with Coliform. Other pathogenic bacteria, including Escherichia coli, Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus and Vibrio cholerae were not found in shrimp paste samples. Conclusion: Evaluation of microbial contamination in popular foods such as shrimp paste should be done regularly to prevent food-born diseases in the community.
Microbial contamination ; Food safety.

Background: Diarrhea is a leading cause of death in children under 5 years old, especially in developing countries. About 12.600 children die because of diarrhea everyday in Asia, Africa and Latin-America. Objective: To identify the main organism that causes diarrhea in children under 5 years old. Subject and Method: The etiology agents of diarrheal children under 5 years old admitted to the Pediatric Hospital in Hai Phong city were studied in the period from September 2006 to August 2007. A total of 968 children were examined for diarrheagenic Escherichia coli (DEC), Salmonella, Shigella, Vibrio, Aeromonas, Campylobacter, these pathogens as being significant bacteria associated with diarrhea. A total of 212 out of 968 cases were positive for bacteria. Result: The main pathogens were diarrheagenic Eschierichiacoli 153 (15.7%), Salmonella 12 (1.24%), Shigella 32 (3.3%). Vibirio paraheamolyticus 1(0.1%), Aeromonas 8 (0.8%), Campylobacter 6(0.6%) from rectal swabs and no Vibrio cholerae was found. The multiplex PCR assays for the identification of DEC was developed. DEC was classified into 6 categories with frequencies of EPEC 3.9%, ETEC 4.4%, EIEC 0.6%, EAggEC 6.7%, DAEC 0.1%, no EHEC was identified. Conclusion: An analysis of incidence of enteropathogens with respect to seasonal variant demonstrated that the frequencies of isolation of etiology agents mainly in July, August and September. This study also showed that diarrheagenic- Escherichia coli is the main organism causing diarrhea in children under 5 years old.
Diarrhea ; enteropathogenic bacteri ; diarrheagenic Eschierichiacoli