The isolates of Salmonella enterica serotype Typhimurium (Salmonella serotype Typhimurium) definitive phage type 104 (DT104) were classified in the same cluster (cluster A) by fluorescent amplified-fragment length polymorphism (FAFLP) (Tamada et al., J. Clin. Microbiol. 39:1057-1066. 2001). Sixteen isolates that belonged to FAFLP cluster A, in which 12 isolates of DT104 were examined, were found to contain same prophage (denoted phage ST104). Restriction patterns with EcoRI revealed that the prophage in isolates of cluster A were different from those in isolates of the other cluster, suggesting that prophage patterns can be used as a marker for serotype Typhimurium DT104. The complete sequence of the DNA genome of prophage ST104 was determined. The entire DNA sequence consisted of 41,391 bp including 64 open reading frames, was very similar to P22 and to phage-type conversion phage ST64T, which was isolated from DT64. The inferred proteins of ST104 that exhibited a high degree of sequence similarity to P22 protein (> 90%) included the functional serotype conversion cassette, integrase, excisonase, Abc1, superinfection exclusion protein (gp17), Antitermination protein (gp24), Ral, Helicase, NinB, NinD, NinE, NinF, NinG, NinY, NinH, packaging (gp3 and gp2), head (with the exception of gp26, gp20, and gp16) and tail protein. Three corresponding ORFs, namely ORF19, ORF47, and ORF48, were present in ST64T but absent in P22. The lysis genes were identical to those of serotype Typhimurium PS119. Taken together, these results show that the genome of ST104 is a genetic mosaic composed of gene modules, which is typical among members of the lambdoid phage family.
(Clinical Microbiology Section, Hokkaido Research Station TEL +81-11-851-5226)
Tanaka et al. (2004) J. Clin. Microbiol. 42:1807-1812.