Abstract
BackgroundLeptospira is the causative agent of leptospirosis. The O-antigen is the distal part of the lipopolysaccharide, which is a key component of outer membrane of Gram-negative bacteria and confers serological specificity. The epidemiology and clinical characteristics of leptospirosis are relative to the serology based taxonomic unit. Identification of Leptospira strains by serotyping is laborious and has several drawbacks.ResultsIn this study, the O-antigen gene clusters of four epidemic Leptospira serogroups (serogroup Canicola, Autumnalis, Grippotyphosa and Hebdomadis) in China were sequenced and all genes were predicted in silico. Adding published sequences of two serogroups, Icterohaemorrhagiae (strain Lai and Fiocruz L1-130) and Sejroe (strain JB197 and L550), we identified six O-antigen-specific genes for six epidemic serogroups in China. PCR assays using these genes were developed and tested on 75 reference strains and 40 clinical isolates.ConclusionThe results show that the PCR-based assays can be reliable and alternative means for rapid typing of these six serogroups of Leptospira.
Highlights
Leptospira is the causative agent of leptospirosis
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 serogroup-specific genes and employed to identify strains isolated from clinical samples
The serology results for all reference strains are consistent with those of the National Institute for the Control of Pharmaceutical and Biological Products
Summary
Leptospira is the causative agent of leptospirosis. The O-antigen is the distal part of the lipopolysaccharide, which is a key component of outer membrane of Gram-negative bacteria and confers serological specificity. The Leptospira genus has been divided into 20 species based on DNADNA hybridization studies. The O-antigen gene cluster of Gram-negative bacteria has been intensively studied These genes encode proteins involved in the biosynthesis of the O-antigen and can be divided into three groups [13]. They are nucleotide sugars precursors’ biosynthesis genes, glycosyltransferase genes and the O-antigen processing genes. O-genotyping has been used successfully in several bacteria genus, such as E. coli [14], S. enterica [15], S. boydii [16], and Y. pseudotuberculosis [17] Target genes of these kinds of methods are mainly the second and the third group genes that encode glycosyltransferase and O-antigen processing proteins
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