[The application of a Salmonella typhimurium biotyping method to the epidemiological surveys and surveillance]

In order to explore a new and effective means to the investigation and surveillance on Salmonella typhimurium infection, the authors applied a biotyping method of S. typhimurium invented by Duguid to the surveillance of nosocomial infection and tracing of infected case as well as cause of food-poisoning. Results showed that the major biotypes of strains isolated from children of acquired nosocomial infection with biotypes of strains from hospital environment and medical staff were quite similar. The biotype of cultures from the urine in a paralytic patient was the same as from the environment of the household and the wife's hands. The biotypes of strains identified from food-poison cases and leftovers was the same as isolated from ducks. It is believed that nosocomicial infection among children was caused by contamination of bacteria in hospital environment and carriers of medical staff. The urinary infection of a paralytic patient was due to environment pollution of the household, but not to nosocomial infection. The food-poisoning case was caused by the consumption of ducks infected with the bacteria.