Jj. Staats et al., Presence of the Streptococcus suis suilysin gene and expression of MRP andEF correlates with high virulence in Streptococcus suis type 2 isolates, VET MICROB, 70(3-4), 1999, pp. 201-211
Nineteen Streptococcus suis type 2 isolates that had been analyzed previous
ly for hemolysin production, ribotype, and virulence in pigs were examined
for presence of the gene coding for suilysin by PCR amplification, and sout
hern blot and hybridization techniques. Based on southern blot and hybridiz
ation analysis, all isolates tested contained at least a portion of the sui
lysin gene. PCR amplification of the entire gene resulted in gene fragments
from five of the seven highly virulent isolates and none of the moderately
virulent or avirulent isolates. Additional PCR analysis showed that mutati
on or deletions at the 5' end of the suilysin gene in the less virulent iso
lates prevented amplification of the sly gene fragment from those isolates.
The MRP+ (muramidase-released protein) EF+ (extracellular protein) phenoty
pe was also expressed by the same five highly virulent/sly+ isolates. (C) 1
999 Elsevier Science B.V. All rights reserved.