Subdivision of Salmonella enterica serovar enteritidis phage types PT14b and PT21 by plasmid profiling

We have shown that plasmid profiling is a sensitive method for further iden tification of strains of Salmonella enterica serovar enteritidis (S. enteri tidis) phage type PT21 and to a lesser extent the strains of phage type PT1 4b Five and three plasmid types were identified within 33 strains of phage type PT21 and 19 strains of phage type PT14b, respectively. Plasmid types i n strains of phage type PT21 showed significant correlation with geographic al origin of the strain. In strains of phage type PT14b a single isolate pr edominated suggesting that the plasmid designated as 'C' can be directly li nked with S. enteritidis PT14b strains, Application of IS200 fingerprinting did not reveal any other differences and showed just one copy of IS200 in all the 52 analysed strains. All the strains were tested for antibiotic res istance and only four strains were resistant to ampicillin, cefotaxime, cef uroxime and cotrimoxazole. This indicates that low molecular weight plasmid s in Salmonella enteritidis are not responsible for the spread of antibioti c resistance. (C) 2000 Elsevier Science B.V. All rights reserved.