Our data showed that cd5, cd6, and cd7 loci did not decrease the congruency with PCR-ribotyping (Table 2; Additional File 2). The result may be due to that the 16S-23S intergenic spacer region, on which the PCR-ribotyping based on, was not as conserved as a housekeeping gene
that is used to construct the phylogenic tree [9, 38]. However, the variations from these incomplete repeat loci should be detected in our follow-up surveillance. PCR ribotyping is a standard technique used worldwide for epidemic clone detection, but the ambiguous Tipifarnib in vitro data generated by this technique is difficult for assessing inter-laboratory efficacy. MLVA is a fast and easy-to-use method, and its numerical profile output is more transferable than the standard PCR ribotyping technique. In our laboratory setting, the cost of PCR ribotyping, MLVA10, and TRST per isolate was $0.87, $2.53, and $13.60, respectively, and the cost of the most recent MLST is $24.65 according to Griffiths’ estimation . In the current study, the cost of
MLVA10 was slightly higher than that of PCR ribotyping, but was still significantly less expensive than the TRST and MLST sequence-based typing techniques. Moreover, when analyzing a large number of isolates, it is simpler to perform one genotyping technique than multiple techniques. Taken together, the MLVA10 is recommended for the detection of C. difficile PCR-ribotype groups and for use in combination with the MLVA panel designed for the detection of outbreak strains. Future studies
will involve evaluation of MLVA10 for 17-AAG mw its phylogenetic information by comparison to MLST typing. Conclusions For the classification of C. difficile strains, the MLVA technique can result in a distinguishable data set that is more useful for comparison and is highly congruent with PCR-ribotype results. The MLVA10 panel may be used either to detect the PCR-ribotype groups or to overcome the drawbacks of the PCR ribotyping technique. In addition, the MLVA4 can be used to detect closely-related strains. These two MLVA panels can be combined and used for epidemiological studies of C. difficile. Methods Bacterial strains A total of 142 C. difficile strains that were either toxigenic or non-toxigenic Megestrol Acetate were used in this study. Five reference strains (NCTC11204, NCTC13366, NCTC13287, NCTC13404, and NCTC13307) were purchased from the National Collection of Type Cultures (NCTC, London, UK) and three reference strains (BCRC17900, BCRC17702, and BCRC17678) were purchased from the Bioresource Collection and Research Center (BCRC, Hsinchu, Taiwan). One strain (NAP1/027) was kindly provided by Dr. Brandi Limbago from the United States Centers for Disease Control and Prevention (CDC), and 133 strains were isolated from clinical laboratory specimens in Taiwan.