Comparison of Common Molecular Typing Methods for Differentiation of Clostridium difficile Strains in the Study of Hospital Acquired Infections

Abstract

Background: Cross-contamination between patients and the medical imaging device is a worldwide concern. In the current study, the ability of different molecular typing methods for differentiation of Clostridium difficile isolates from patients and medical devices was compared to show their discriminatory power for molecular epidemiological purposes. Methods: A total of 23 C. difficile strains from fresh stool samples of patients subjected to colonoscopy, medical device, and environmental samples of a gastroenterology unit were used for molecular typing. Similarity of the strains was determined by the polymerase chain reaction (PCR) ribotyping, capillary gel electrophoresis based-ribotyping, and RAPD-PCR and ERIC-PCR methods. Phylogenetic analysis of the molecular patterns was done by the GelCompar II software and discriminatory power of the methods was measured using Simpson’s index diversity. Results: RAPD-PCR and PCR-ribotyping methods showed the highest discrimination power for differentiation of the studied strains, while genotyping showed the lowest power. Similarity of C. difficile strains between the patients and medical equipment was detected for the strains presenting PCR-ribotypes B and CE-ribotype 150. Conclusions: Involvement of medical device for transmission of toxigenic strains of C. difficile was determined in this study. Although diversity of C. difficile strains was established in the studied hospital, a discrepancy was detected among these techniques for typing purposes. The results suggested the usage of a combination of two or more typing methods for detection of sources of cross-contamination in each hospital.