Molecular typing of Salmonella enterica subsp. enterica serovar Wien by rRNA gene restriction patterns.

Analysis of digested DNA from 40 Salmonella enterica subsp. enterica serovar Wien isolates revealed five different rRNA gene restriction patterns for HindIII (H1 to H5) and five for PstI (P1 to P5). The isolates had been selected on the basis of the year of isolation, the geographic origin and the antibiotic resistance pattern and were distinguished as follows: a) 13 pre-epidemic isolates from different French towns in 1958-69 and from Senegal in 1968; b) 7 epidemic isolates from Algiers in 1969; c) 20 post-epidemic isolates from different French and Italian towns in 1970-90. Three different rRNA patterns (H1P1, H3P3 and H4P4) were observed among the pre-epidemic isolates. Conversely, the epidemic isolates, which were characterized by the previously described large antibiotic resistance patterns and by the presence of 1.3 and 80-109 MDa plasmids, belonged to the same H1P1 ribotype. All but two post-epidemic isolates were of the H1P1 ribotype. The determination of rRNA gene restriction patterns together with the plasmid content proved to be useful for a better characterization of the serovar Wien endemic and epidemic isolates.