Subdivision of Salmonella enteritidis PT 4 by pulsed-field gel electrophoresis: potential for epidemiological surveillance.

Using pulsed-field gel electrophoresis (PFGE), nine profile types were identified in XbaI digests of a panel of strains of Salmonella enteritidis phage type 4 (PT 4) isolated in England and Wales between 1967 and 1992. When applied to 39 isolates from humans, chickens, poultry products and feed, strains belonging to pulsed-field profile (PFP) 1 predominated. DNA-DNA hybridization studies demonstrated that a band of approximately 57 kb was associated with the presence of the 38 MDa S. enteritidis 'serovar-specific' plasmid. It is concluded that PFGE provides a method for discriminating strains of S. enteritidis PT 4 suitable for epidemiological investigations.