Hypervirulent C. difficile (IMAGE) University of California - Irvine Caption The VPI10463 and M68 represent the classic and the hypervirulent C. difficile, respectively. GTD-VPI preferentially modifies Rho family GTPases (Cdc42, for example) by glucosylation, while GTD-M68 more effectively modifies R-Ras. Due to their different selectivity toward Rho or Ras family GTPases, these two different TcdB variants cause two distinct types of cytopathic effects. Credit UCI School of Medicine Usage Restrictions No restrictions License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.