PCR Based Detection of B1/NAP-1/027 Strain of Clostridium Difficile: Decrease in Prevalence and Clinical Severity?
Daniel A Smith, Cary Chisholm, Arundhati Rao, Kimberly Hocker. Scott and White Hospital, Temple, TX
Background: Clostridium difficile (C. difficile) infections are an increasing cause of healthcare associated infections. The B1/NAP-1/027 (PFGE type B1/NAP1, also called ribotype 027) strains carry mutations in the negative regulator tcd C gene, leading to greatly increased toxin A and B production (up to 20% more) with pronounced colonic injury. Though this strain has been associated with the rise in C. difficile associated disease (CDAD), recent reports in Europe indicate that the prevalence is actually decreasing. We report on the prevalence and clinical features of this strain in our population.
Design: We developed a PCR based Light Cycler assay to detect this mutation on 1,979 C. difficile PCR positive samples. Additionally, we examined tissue and stool samples from 24 patients with a histologic diagnosis of pseudo-membranous colitis. The overall morbidity and mortality of the mutated strain is compared to the non-mutant strain.
Results: There were 544 C. dificile PCR positive cases in 2008, 984 in 2009 and 451 cases to date in 2010. The percentage of positive C. difficile cases is 10 %. The percentage of the ribotype 027 strain in the PCR positive C. difficile cases is 9% for each year since 2008. The mortality rate of the non-ribotype 027 strain group was 11% which was significantly higher than the ribotype 027 group. Additionally, There were no ribotype 027 strains detected in tissue or stool samples patients with pseudo-membranous colitis.
Conclusions: The prevalence of C. difficile B1/NAP-1/027 strains is stable and is not increasing in the Central Texas population. Additionally, this strain is not associated with greater mortality and morbidity compared to the wild-type strain.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 19, Wednesday Morning