Molecular analysis of Salmonella enteritidis isolates resistance to ampicillin and streptomycin from three outbreaks of food poisoning in Shiga Prefecture

In 1998 and 1999, there were three outbreaks caused by Salmonella Enteritidis in Shiga Prefecture. One outbreak was suspected to be a diffuse outbreak, caused by frozen cream puffs that had been sold in chain stores throughout Shiga. Prefecture between the beginning of September and the beginning of October, 1998. The other outbreaks occurred in May and in August, 1999. All isolates of the three outbreaks showed an identical lysis pattern against the typing phage, though this pattern did not conform to the current scheme, so-called RDNC. In addition all isolates were resistant to ampicillin and streptomycin. However, the patterns of pulsed-field gel electrophoresis strongly indicated that the three outbreaks were actually independent.