Analyzing the O-antigen gene clusters of 8 sequenced strains (Lai, Fiocruz L1-130, JB197, L550, Gui44, Lin4, Lin6, and C401), we developed simple and practical PCR assays for six epidemic serogroups in China [32] that target this website serogroup-specific

genes and employed to identify strains isolated from clinical samples. Results and Discussion MAT All strains, including 75 reference strains and 40 isolated strains, were tested by MAT with standard rabbit serum. The results are shown in additional file 1 Table S1 and additional file 2 Table S2. The serology results for all reference strains are consistent with those of the National Institute for the Control of Pharmaceutical and Biological Products. Of the 40 isolated strains, 7 strains belong to serogroup Icterohaemorrhagiae,, 5 strains belong to serogroup Autumnalis, 11 strains belong click here to serogroup Grippotyphosa, 1 strain belongs to serogroup Hebdomadis and 5 strains belong to serogroup Sejroe. 5 isolated strains were validated by MAT as Serogroup Ballum, Australis, Javanica and Sarmin, respectively. Six strains were unable to be classified. None of strains belong to serogroup Canicola Development of PCR-Based Assays We assigned functions of all ORFs by comparing homology genes. Most of predicted proteins are shown to be related LDC000067 solubility dmso to O-antigen

biosynthesis except for some hypothetical proteins (see additional file 3 Table S3-6). For typing bacteria, several different approaches have been used in Leptospira. Serological typing is based on strain to strain differences in the structure

of lipopolysaccharide, mainly in the structure of the O-antigen. Recently, PCR-based typing methods targeting specific genes were employed for dicrimination certain serogroups of several bacteria [14–17]. These targeted genes are mainly those encoding glycosyltransferase and enzymes involved in O-antigen assembly. Among them, two highly specific genes: wzx (encode O-unit flippase) and wzy (encode O-antigen polymerase), are O-genotyping targets, usually. Previous analysis of the O-antigen of Leptospira showed that the biosynthesis of LPS in Leptospira Dipeptidyl peptidase is a Wzy-dependent pathway [12, 33]. In conjunction with published data [34], our comparison of the O-antigen clusters in all 8 strains shows that the Wzy protein has a high identity among the different serogroups. Similarly, Wzx shows high similarity across other serogroups (data not shown). So we discarded these two genes as PCR assays targets. To identify highly specific genes for PCR typing, we analyzed all predicted ORFs by the BLAST program. First, we selected genes that exhibit less than 70% amino acid similarity with their counterpart genes. Second, we compared these selected genes with draft data generated by 454 sequencing and discarded genes with more than 70% nucleotide similarity to any sequence in the draft data.