Multilocus sequence typing of 33 clinical Clostridium difficile isolates

Objective To investigate the multilocus sequence typing (MLST) for clinical Clostridium difficile isolates in Shijiazhuang of China. Methods A laboratory-based study was carried out retrospectively to characterize 33 C.difficile strains isolated from diarrhea patients during July 2010 to December 2011 according to toxin types,PCR ribotyping and MLST.START2 system was used to analyze the results. Results Ten ST types (ST2/3/4/35/37/53/54/55/102/172) and 12 PCR ribotyping were identified in 33 C.difficile strains.The most prevalent ST types and PCR ribotyping were ST37/SⅠ (9/33,27.3%) and ST54/SⅢ (8/33,24.2%).ST172 was a new ST type reported firstly in the world,and has been included in the MLST database.Phylogenetic analysis also revealed that 6 STs (ST2,ST3,ST4,ST53,ST54,ST102) were placed in one large group.Genotypes ST35,ST37,ST55,ST172 were considered as singletons. Conclusions The most common ST types for 33 clinical C.difficile strains isolated from Shijiazhuang were ST37 and ST54.No significant homology was found between ST types and hospitals.(Chin J Lab Med,2013,36:920-925) Key words: Clostridium difficile; Molecular typing; PCR ribotyping; Multilocus sequence typing