The study was performed on 90 Salmonella typhi strains isolated from patients in Hanoi, Hue and Ho Chi Minh city. The results showed that: the multi-antibiotic resistant Salmonella typhi strains have already spread over the country; 2 plasmid with size about 120 kilobase (Kb) and 102 Kb. Plasmid 120 Kb is conjugated, self-transmitted R-plasmid and carrying at least 5 antibiotic resistant genes to chloramphenicol, ampicillin, tetracycline and trimethoprim/sulfamethoxazole. The initial analysis by a restricted enzyme of EcoRi showed that these self-transmitted R-plasmid in S.typhi strains isolated in 3 areas Hanoi, Hue and Hochiminh city maybe the same origin.
Salmonella typhi ; R Factors ; epidemiology

Study on 884 children under age of 5 years old (627 diarrhea children, 257 healthy children) at 4 places: National Pediatric Hospital, Saint Paul Hospital, Thanh Nhan Hospital and Kim Lien primary school from March 2001 to April 2002. The results: the most prevalent pathogen was Rotavirus with the prevalence of 45% in children under 5 years old with diarrhea, E.Coli was the second commonly pathogen, was isolated by PCR technique with the rate of 24% in diarrhea children, 12% in healthy children and then Shigella with 3.2% in diarrhea children. No Salmonella and V.cholerae strains were identified PCR was used as effective method to indentify and differenciate diarrheagenic E.Coli strains
Child ; Age Factors ; Schools ; Diarrhea