National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2003

11. Chloramphenicol resistance transposon TnSs1 of Streptococcus suis

Japanese

   Streptococcus suis is a Gram-positive bacterium of increasing importance in pig production throughout the world. Although conjugative transfer of erythromycin, tetracycline, or kanamycin resistance that is possibly mediated by a conjugative transposon has been reported in S. suis, genetic organization of antibiotic resistance transposons isolated from S. suis has not thus far been reported. Here we report a new chloramphenicol resistance transposon (TnSs1) found in a field isolate of S. suis. The transposon consists of a chloramphenicol acetyltransferase gene sandwiched between two directly repeated IS6-family elements (IS214L and IS214R). Polymerase chain reaction and Southern hybridization analyses indicated that another field isolate harbored the same transposon in a different location on the chromosome. A transposition assay done with a temperature sensitive suicide vector showed that, among the seven TnSs1 mutants tested in this study, six formed a cointegrate between the S. suis chromosome and the vector, with the generation of a third copy of the IS214 element, and one carried one copy of TnSs1 on the chromosome as a result of a subsequent resolution step. These results demonstrate that TnSs1 is an active mobile genetic element.
(Molecular Bacteriology Section, Department of Infectious Diseases   TEL +81-29-838-7743)

References:

Takamatsu et al. (2003) Plasmid 49:143-151.

Centers・Institutes