| Strangle is an acute and highly contagious disease,that caused by Streptococcus equi subspecies equi(S.equi),the typical symptoms of the disease is fever purulent nasal fluid and lymph node abscesses in the head and neck,andit also lead to death of horse when it become serious.This disease is widely in world and has caused serious economic losses to the horse breeding industry.At present,epidemic mostely focused on a few identified virulence factors of S.equi,and few studies have been conducted on the evolutionary relationship and genetic characteristics of S.equi endemic strains in Xinjiang based on the genome-wide background,which limits the understanding about the pathogenic mechanism and prevention and control of S.equi at the genome-wide level.In this study,Xinjiang isolate XJ 5012 was cultured,immungenicity cultural and histopathological characteristics were investigated using mouse model.The results showed the growth curve,immunological characteristics and pathological characteristics of the bacterium.In this study,genomic features and evolutionary characteristics of Xinjiang isolate XJ 5012 was analyzed via whole genome sequencing and bioinformatics analysis,and comparative genomic analysis was performed between the isolate,S.equi 4047 and S.equi NCTC12091 to understand the differences between the three strains at the genomic level.XJ 5012 genomic DNA was sequenced using IIumina and Pac Bio RS II sequencing analyzer,genomic of XJ 5012 contained one circular chromosome of 2.21 Mb and a circular plamisd of 15 805 bp,genome analysis results showed that XJ 5012 had 2 264 coding genetic,66 t RNA,18 r RNA,13 genetic islands,10 CRISPR structures and 3 prophages.16S r RNA gene phylogenetic analysis indicated that the S.equi XJ 5012 had the closest relationship with S.equi 4047.Analysis results of the Se M in the Pub Med database shows that,the new genotypes identified isolates XJ 5012 Se M-215,which closely relate to isolate Se M-209 and Se M-217 in Xinjiang,and isolates Se M-195 and Se M-196 foreign isolates.Comparative analysis result indicated that the 197 virulence genes and 135 resistance genes were found in VFDB and CARD database.Resistance genes were mainly divided into macrolide,fluoroquinolone,aminoglycoside,peptide,tetracycline and ?-lactam antibiotic resistance genes.In this study,a comparative genomic analysis of XJ 5012,S.equi 4047 and S.equi NCTC12091 showed that they are closely related,and the difference was that there was an invertion between the fragment 1 178 646 bp-1 191 423 bp on XJ 5012 was in the S.equi 4047 genome 2 196 103 bp-2 208 413 bp.The pan-genome analysis results of three strains indicated that they had 1 602 core genes,accounting for 69.59% of the total gene cluster,more non-core gene clusters were shared between XJ 5012 and S.equi4047.16 S r RNA phylogenetic tree indicated that these two strains closes relative.The homology of various virulence genes was compared,and it was found that Se M gene and Ide E2 gene were not found in S.equi NCTC12091,and the homology of XJ 5012 and S.equi 4047 genes was around 99.2%-100%.To sum up in,this study the culture characteristics of strain XJ 5012,antigen characteristics and pathological characteristics were investigated and the whole genome sequence of this strains was analyzed new genotypes Se M-215 was identified,the results provide data support and theoretical basis for the subsequent screening of S.equi virulence genes and the study of pathogenesis of S.equi. |
PDF Full Text Request