756. Molecular Characterization of Clostridium difficile from Patients with Hospital Acquired C. difficile Infection (CDI), 20062009, Houston, Texas
Session: Oral Abstract Session: Clostridium difficile: Detection, Transmission, and Treatment
Friday, October 21, 2011: 3:00 PM
Room: 151AB
Background: Clostridium difficile is a major cause of hospital-acquired antibiotic-associated diarrhea, colitis and pseudomembranous colitis. Typing C. difficile isolates is the only known way to study the epidemiology of CDI in the hospital setting and to determine the presence of a disease outbreak.

Methods: The study examined consecutive C. difficile isolates identified from patients with CDI in a large teaching hospital in Houston, TX between 2006 and 2009. In the present study, 198 C. difficile isolates were analyzed by four molecular typing methods - repetitive extragenic palindromic elements (REP), conserved repetitive DNA elements (BOX), enterobacterial repetitive PCR intergenic consensus sequences (ERIC) and ribotyping.

Results: REP was able to type 81% of the isolates examined, as comparison to 94%, 98% and 100% for BOX, ribotype and ERIC respectively. Cluster analyses using the four assays confirmed the presence of nine distinct groups of C. difficile. Strains in each group had a >75% similarity level with between group similarity of <60%. Among nine identified groups, REP I, BOX I, ERIC II and ribotype II were the most common types identified (including 22 isolates [11%]), followed by REP I, BOX III, ERIC I and ribotype II (14 isolates [7%)), REP II, BOX II, ERIC III and ribotype II (4 isolates [4%]). Forty of 198 (20%) C. difficile isolates belonged to one of the definable clusters. We failed to identify regions of the hospital where definable clusters were concentrated. We did not observe phylogenetic group changes over the study years.

Conclusion: These findings suggest complex epidemiology with presence of different C. difficile strains being found in one large teaching hospital in Houston over the 4 years of the study. The findings of this study suggest the presence of multiple sources for strain importation of C. difficile strains into a hospital which complicates infection control approaches.  Additional study is needed to better understand the epidemiology and transmission of strains of C. difficile in the hospital environment.

Subject Category: B. Bacterial pathogenesis, studies in animal models, molecular pathogenicity

ZhiDong Jiang, MD, PhD, The University of Texas Houston School of Public Health, Houston, TX, Herbert DuPont, MD, St. Luke's Episcopal Hospital and Kelsey Research Foundation and Kelsey-Seybold Clinic, Houston, TX; University of Texas, School of Public Health, Houston, TX; Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, Todd M. Lasco, PhD, Clinical laboratory, Saint Lukes Episcopal Hospital, Houston, TX and Kevin Garey, PharmD, University of Houston College of Pharmacy, Houston, TX; University of Houston, St Lukes Episcopal Hospital, Houston, TX


Z. Jiang, None

H. DuPont, None

T. M. Lasco, None

K. Garey, None

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