Epidemiological analysis of Salmonella enteritidis isolates using pulsed-field gel electrophoresis and bacteriophage typing over the period of April 2000 to March 2003 in Gifu Prefecture

Abstract

We examined a total of 151 Salmonella enterica serovar Enteritidis strains isolated in Gifu Prefecture during the period from April 2000 to March 2003 by using bacteriophage typing and pulsed-field gel electrophoresis (PFGE). Bacteriophage typing classified them into twelve phage types (PT) and RDNC (reacted but did not conform). The predominant phage type was PT47 (34.4%) followed by PT1 (21.9%), PT4 (16.6%) and RDNC (11.3%). XbaI- and BlnI-digested PFGE analyses identified 17 and 44 PFGE patterns, respectively, indicating that PFGE with BlnI had more discriminating power than that with XbaI. Combination of the phage types and PFGE types of BlnI could make 53 subtypes. Some isolates with the same phage type were subdivided into different PFGE types, but those with PT47 were not. PT47 isolates were derived from sporadic patients with gastroenteritis, food poisoning outbreaks and healthy carriers through the years. This suggests that PT47 is highly clonal and disseminates over our prefecture.