The Emergence ofClostridium difficileInfection among Peripartum Women: A Case-Control Study of aC. difficileOutbreak on an Obstetrical Service

Objective . An outbreak of 20 peripartum Clostridium difficile infections (CDI) occurred on the obstetrical service at the University of Washington Medical Center (UWMC) between April 2006 and June 2007. In this report, we characterize the clinical manifestations, describe interventions that appeared to reduce CDI, and determine potential risk factors for peripartum CDI. Methods . An investigation was initiated after the first three peripartum CDI cases. Based on the findings, enhanced infection control measures and a modified antibiotic regimen were implemented. We conducted a case-control study of peripartum cases and unmatched controls. Results . During the outbreak, there was an overall incidence of 7.5 CDI cases per 1000 deliveries. Peripartum CDI infection compared to controls was significantly associated with cesarean delivery (70% versus 34%; P = 0.03 ), antibiotic use (95% versus 56%; P = 0.001), chorioamnionitis (35% versus 5%; P = 0.001), and the use of the combination of ampicillin, gentamicin, and clindamycin (50% versus 3%; P < 0.001 ). Use of combination antibiotics remained a significant independent risk factor for CDI in the multivariate analysis. Conclusions . The outbreak was reduced after the implementation of multiple infection control measures and modification of antibiotic use. However, sporadic CDI continued for 8 months after these measures slowed the outbreak. Peripartum women appear to be another population susceptible to CDI.