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

Background: Classification of vibriophages has been applied for epidemiological surveillance of cholera, but in Vietnam, there was virtually no knowledge about it. It is very important to determine whether the strains have common origin or different origins.Objectives: To classify vibriophages isolated from environmental surface water samples in Thai Binh in order to monitor cholera outbreaks. Subjects and method: Three vibriophages (84, 87, and 811) were collected from surface water samples in Thai Binh in 2006. Electronic microscopy was used to compare the size and morphology of Vibrio phages. Also, the structures of genomic DNA of vibriophages were compared by hind III digestion pattern and Southern blotting. Results: Vibriophages S4 and S11 isolated from Thai Binh were similar to kappa phage (a phage produced by V. cholerae 01 EI Tor strain), phage IV (a phage produced by V. cholerae 01 classical strain) in term of morphology and genome and were the same shape and DNA dimension of phage 1823 isolated from V. cholerae O139 strain in India and Bangladesh. Conclusion: Phage 84, 81 isolated from Thai Binh were new kinds of vibriophage isolated in Viet Nam. These findings were very useful for supervising and controlling cholera outbreaks in Vietnam.
Classification ; vibriophage ; environment surface water

Background: In countries that cholera outbreaks commonly occurs, surveillance of surface water is important to control the epidemics. Kappa phage (K139) of Vibrio cholerae is related to epidemic El Tor and O139 strains in various countries. Objectives: To study the relationships between V. cholerae 01 and vibriophages in surface water in Thai Binh and Hai Phong city and to determine the predictors of cholera outbreaks. Subjects and method: Total of 82 water samples were collected by shrimp swab method in Hai Phong and Thai Binh in June and September 2007, where cholera outbreaks occurred. The enriched culture method and direct peR were applied to define the relationships between vibriophages and V. cholerae 01 in surface water. Results: The rates of detecting kappa junction with chromosomes of V. cholerae 01 in Hai Phong and Thai Binh were 10% and 15% in June 2007, 35% and 41% in September 2007. The rates of detecting vibriophages in Hai Phong and Thai Binh were 15% and 15% in June 2007, 25% and 36% in September 2007. The rates of Fs1 and Fs2 detected by PCR method were 70% and 100% in Hai Phong at June and September 2007, and were 57% and 100% in Thai Binh at June and September 2007, respectively. V. cholerae 01, O139 weren\u2019t found in water samples. Conclusion: The presences of vibriophages (kappa phage and fs1 fs2) in surface water contaminated with V. cholerae 01 were dependent on the ability of the vibriophages to infect and lyse these bacteria. Vibriophages played a role in the transfer of cholera toxin and pathogenic factors. Surveillance by detecting V. cholerae 01 and vibriophages in surface water may be a feasible means of predicting outbreaks of cholera before a significant number of cases occur.
Vibrio cholerae 01 ; vibriophages ; surface water ; cholera outbreaks

OBJECTIVES: Lysosome is the cell-organelle which is commonly used as biomonitoring tool in environmental pollution. In this study, the lysosomal proteomic of the yeast Saccharomyces cerevisiae was analyzed for utilization in the detection of toxic substances in mine water samples. METHODS: This work informs the expression of lysosomal proteomic in yeast in response with toxic chemicals, such as sodium meta-arsenite and tetracycline, for screening specific biomarkers. After that, a recombinant yeast contained this biomarker were constructed for toxic detection in pure toxic chemicals and mine water samples. RESULTS: Each chemical had an optimal dose at which the fluorescent protein intensity reached the peak. In the case of water samples, the yeast showed the response with sample 1, 3, 4, and 5; whereas there is no response with sample 2, 6, and 7. CONCLUSIONS: The recombinant yeast showed a high ability of toxic detection in response with several chemicals such as heavy metals and pharmaceuticals. In the case of mine water samples, the response varied depending on the sample content.
Environmental Monitoring ; Environmental Pollution ; Lysosomes ; Mass Screening ; Metals, Heavy ; Saccharomyces cerevisiae* ; Sodium ; Tetracycline ; Water* ; Yeasts ; Biomarkers