The genome of "S. suis" isolates from the outbreak were examined to see whether its DNA sequence could explain why these particular bacteria were able to cause STSS. However, none of the genes that are present in "S. pyogenes" and thought to cause STSS were detected in the "S. suis" isolates. Comparison with other "S. suis" isolates from around the world, including one from an earlier smaller "S. suis" outbreak in Sichuan province that killed 14 out of 25 reported human cases, revealed that the two Chinese isolates were more similar to each other than to any other strains.