Abstract
In Hiroshima city, when medical facilities report the occurrence of a sporadic food poisoning case to the public health center, the center collects the bacterial isolate and the isolate is tested for serotype, antibiotics susceptibility and other attributes at the institute of public health to monitor trends in food poisoning. This surveillance system has noted the gradually increasing tendency toward Salmonella serogroup O7 isolates since the end of 1998 that were almost all serotyped as Salmonella Oranienburg, suggesting an epidemiological relation between these isolates. Therefore, we evaluated the availability of random amplified polymorphic DNA (RAPD) method as a molecular-epidemiological technique for comparison of them and investigated food poisoning cases by applying RAPD and other techniques, including pulsed-field gel electrophoresis (PFGE), to the isolates. Most Salmonella isolates showed the same RAPD and PFGE patterns. Consequently, the investigation by these techniques and field-epidemiological data revealed that the sporadic food poisoning cases in Hiroshima city were a diffuse outbreak due to cuttlefish chips contaminated by not only S. Oranienburg but also S. Chester. The RAPD method was a rapid and useful tool for molecular-epidemiological approach to this outbreak.
