社区获得性ST59型MRSA HZW450的全基因组测序及分析

目的对1例脓疱疮患者脓液中分离的1株社区获得性耐甲氧西林金黄色葡萄球菌(CA-MRSA)HZW450菌株进行全基因组测序并对序列信息解析。方法使用三代测序PacBio技术对HZW450菌株进行全基因组测序,且使用SMRTanalysis v.R2.3.0对该序列进行序列拼接,上传NCBI进行基因功能注释,用RPSBLAST program进行直系同源簇(COG)注释以及毒力因子相关基因和耐药基因分析。同时比较国内其他地区发现的同一序列型(ST)的菌株毒力因子相关基因及耐药相关基因的差异,并比较HZW450菌株耐药基因型与表型的一致性。结果 HZW450菌株的基因组大小为2 831 958bp,GC占比32.9%,其基因组完成图序列已提交至NCBI GenBank数据库,登录号为CP020741。同时经过分析发现该菌株为ST59型,其基因组中含有许多与致病相关的毒力因子,以及含有耐药基因aph(3′)-III、ant(6)-Ia、mecA、norA、erm(B)和cat(pC233),毒力及耐药基因与ST59型其他菌株比较有差异。该菌株临床药敏结果与耐药基因比较分析发现,耐药表型与基因型存在差异。结论本研究报道了1株CA-MRSA(HZW450)菌株的全基因组序列。基因序列分析显示该菌株携带大量毒力基因,包括lukS-PV、lukF-PV、eta、fnbA、fnbB、sspB、sspC等,编码毒素、粘附、免疫逃逸等相关毒力因子,其毒力较强,致病性较高。

Genomic analysis of community acquired methicillin-resistant Staphylococcus aureus HZW450

Abstract: Objective To analyze the genomic characteristics of a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) HZW450 isolated from a patient with impetigo herpetifomis. Methods The whole genome was sequenced using PacBio sequencing techniques. The assembling, annotation, gene prediction, cluster of orthologous group, virulence and antibiotic resistance genes analysis were performed with different software respectively. The relevant genes of virulence factors and antibiotic resistance were analyzed and compared among the same sequencing-type (ST) isolates in China. Results The genome of HZW450 was consisted of a single circular DNA chromosome of 2,831,958 bp with 32.9% GC. The sequence was submitted to GenBank, and the accession number was CP020741. The HZW450 strain was found to belong to ST59 and has numerous virulence factors and antibiotic resistance genes including aph(3'')-III, ant(6)-Ia, mecA, norA, erm(B) and cat(pC233). Compared to the other strains with the same sequencing type, HZW450 had different virulence factors and antibiotic resistance. Antimicrobial susceptibility test and antibiotic resistance analysis showed that there were differences between its genotypes and phenotypes. Conclusion This study reported the whole genome of CA-MRSA HZW450, which contains a large number of virulence genes including LukS-PV, lukF-PV, eta, nbA, fnbB, sspB andsspC, etc. The encoding virulence factors of these genes were related with toxin, adhesion and immune escape, inducing its higher virulence and pathogenicity.