Infection Control & Hospital Epidemiology

Original Articles

Clostridium difficile Outbreak Strain BI Is Highly Endemic in Chicago Area Hospitals

Stephanie R. Blacka1 c1, Kingsley N. Weavera1, Roderick C. Jonesa1, Kathleen A. Ritgera1, Laurica A. Petrellaa2, Susan P. Sambola2, Michael Vernona3, Stephanie Burtona4, Sylvia Garcia-Houchinsa4, Stephen G. Webera4, Mary Alice Lavina5, Dale Gerdinga2, Stuart Johnsona2 and Susan I. Gerbera3

a1 Communicable Disease Program, Chicago Department of Public Health, Chicago, Illinois

a2 Research Service, Edward Hines Jr. Veterans Affairs Hospital and Infectious Disease Division, Department of Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois

a3 Communicable Disease Program, Cook County Department of Public Health, Oak Forest, Illinois

a4 Section of Infectious Diseases and Global Health, University of Chicago Medical Center, Chicago, Illinois

a5 Section of Infectious Diseases, Rush University Medical Center, Chicago, Illinois


Objective. Describe the clinical and molecular epidemiology of incident Clostridium difficile infection (CDI) cases in Chicago area acute healthcare facilities (HCFs).

Design and Setting. Laboratory, clinical, and epidemiologic information was collected for patients with incident CDI who were admitted to acute HCFs in February 2009. Stool cultures and restriction endonuclease analysis typing of the recovered C. difficile isolates was performed.

Patients. Two hundred sixty-three patients from 25 acute HCFs.

Results. Acute HCF rates ranged from 2 to 7 patients with CDI per 10,000 patient-days. The crude mortality rate was 8%, with 20 deaths occurring in patients with CDI. Forty-two (16%) patients had complications from CDI, including 4 patients who required partial, subtotal, or total colectomy, 3 of whom died. C. difficile was isolated and typed from 129 of 178 available stool specimens. The BI strain was identified in 79 (61%) isolates. Of patients discharged to long-term care who had their isolate typed, 36 (67%) had BI-associated CDI.

Conclusions. Severe disease was common and crude mortality was substantial among patients with CDI in Chicago area acute HCFs in February 2009. The outbreak-associated BI strain was the predominant endemic strain identified, accounting for nearly two-thirds of cases. Focal HCF outbreaks were not reported, despite the presence of the BI strain. Transfer of patients between acute and long-term HCFs may have contributed to the high incidence of BI cases in this investigation.

(Received February 14 2011)

(Accepted April 22 2011)


c1 2160 West Ogden Avenue, Chicago, IL 60612 (