[d-Tartrate-positive Salmonella paratyphi B (var. java): lysotype of 1200 strains isolated in France (1975-1985)].

The 1200 d-tartrate positive (dt+) strains of S. paratyphi B, isolated in France during the period 1975-1985, were studied with the aid of the Felix and Callow phage-typing system and the results were compared with those of the study of 1945 d-tartrate negative (dt-) strains of S. paratyphi B examined by means of the same phage-typing method. 2359 dt+ and dt- strains were typable and could be assigned to 25 recognized phage-types. A great variation in the number of strains of each biovar was observed in some phage-types. The proportion of dt+ strains was very high (more than 80%) in four of the most frequent phage-types: 1 var. 3 (87.5%), 1 var. 4 (88.1%), Battersea (90.4%), Worksop (100%); but this proportion was low or very low in eight other frequent phage-types: 1 (29%), BAOR (21.1%), 3aI var. 1 (6.1%), Beccles (5.1%), 3aI var. 4 (4.8%), Dundee (4.7%), 3aI (2.7%), Taunton (2.1%). No recognized phage-type found in France can be considered to be specific of the variety java of S. paratyphi B, with the exception of the phage-type Workshop of all which 76 strains were dt+. On the other hand, 422 dt+ strains were atypical and 93 other were untypable by phages. Among 211 dt+ strains isolated from frozen foods imported from South East Asia, 81.3% were atypical. Six new atypical phage-types were defined and proposed for inclusion into the phage-typing schema which is commonly used in epidemiological investigations on human and animal infections due to either of the two biovars of S. paratyphi B.