Does Recurrent Clostridium difficile Infection Mean Reinfection or Relapse?

Both nosocomial and community-acquired Clostridium difficile infections are becoming common enough that when patients have repeated infections, distinguishing between relapse and reinfection often is difficult. Making this distinction can be important both for tracking and for management.

Researchers used a polymerase chain reaction assay to type organisms from 134 paired stool isolates obtained from 102 patients with recurrent C. difficile infections who were seen during 30 months at a single New York City hospital; 24 patients had three or more episodes. Among stool isolates obtained 2 to 8 weeks apart, 88% yielded identical strains, which suggested relapse rather than reinfection; among isolates obtained 8 weeks to 11 months apart, 65% yi…