1株非典型脑脓肿患儿分离化脓链球菌的生物学特征和基因组特征  

Biological characteristics and genomic features of Streptococcus pyogenes isolated from a child with atypical brain abscess

作　　者：周瑾思 胡玮琳[2] 华春珍[1] 周明明[3] 尤元海[4] Zhou Jinsi;Hu Weilin;Hua Chunzhen;Zhou Mingming;You Yuanhai(Department of Infectious Diseases,Children′s Hospital,Zhejiang University School of Medicine,Hangzhou 310051,China;Department of Medical Microbiology,Zhejiang University School of Medicine,Hangzhou 310058,China;Department of Clinical Laboratory,Children′s Hospital,Zhejiang University School of Medicine,Hangzhou 310051,China;National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases,National Institute for Communicable Disease Control and Prevention,Chinese Center for Disease Control and Prevention,Beijing 102206,China)

机构地区：[1]浙江大学医学院附属儿童医院感染科,杭州310051 [2]浙江大学医学院医学微生物学系,杭州310058 [3]浙江大学医学院附属儿童医院检验科,杭州310051 [4]传染病溯源预警与智能决策全国重点实验室,中国疾病预防控制中心传染病预防控制所,北京102206

出　　处：《中华微生物学和免疫学杂志》2025年第3期223-230,共8页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金(81971951)。

摘　　要：目的对1株分离自非典型脑脓肿患儿脓液的化脓链球菌进行生物学特性和基因组特征分析。方法化脓链球菌21SPY7071(emm22型)分离于脑脓肿手术患儿的脑脓肿标本,采用血平板接种、革兰染色、生长曲线测定和溶血性分析确定该分离株的生物学特性。全基因组测序分析菌株的核心基因组多位点序列分型(core genome multilocus sequence typing,cgMLST)、毒力基因及耐药基因分布情况。qRT-PCR法检测21SPY7071株与化脓链球菌ATCC 19615(emm80型)和GAS029临床株(emm22型)毒力基因mRNA表达水平差异。结果该菌株为革兰阳性链球菌,非典型弱β溶血。全基因组测序和cgMLST分型结果显示,该分离株cgST型别为65937,含有187个毒力基因和97个耐药基因,其中化脓链球菌主要毒力因子编码基因序列与毒力因子数据库序列相似度在95.16%~100.00%。与化脓链球菌ATCC 19615和GAS029临床株相比,21SPY7071株溶血素S基因sagABCDEFGHI、溶血素O基因slo、链道酶基因endA/sdaB表达量均降低。与化脓链球菌ATCC 19615株相比,该分离株毒力基因speG、ideS/mac、hylA、smeZ、lmb、scpA/scpB表达量也均降低。结论本研究中分离自非典型脑脓肿患儿脓液的化脓链球菌溶血性弱,毒力基因表达水平低,或与患儿临床症状轻微相关。ObjectiveTo analyze the biological characteristics and genomic features of a Streptococcus pyogenes strain isolated from the pus of a child with an atypical brain abscess.MethodsThe Streptococcus pyogenes strain,named 21SPY7071(emm22 type),was isolated from the brain abscess specimen of a child undergoing surgery for brain abscess.The biological characteristics of this strain were analyzed using blood agar culture,Gram staining,growth curve measurement,and hemolytic analysis.After whole-genome sequencing,core genome multilocus sequence typing(cgMLST)was performed to analyze the cgST type of the strain,and the distribution of virulence genes and drug resistance genes were analyzed.qRT-PCR was used to detect the differences in the expression of virulence genes at mRNA level between the strain 21SPY7071 and two Streptococcus pyogene strains of ATCC 19615(emm80 type)and GAS029(emm22 type,clinical isolate).ResultsThe strain 21SPY7071 was a Gram-positive Streptococcus with atypical weakβ-hemolysis.Whole-genome sequencing and cgMLST revealed that this isolate belonged to the cgST type of 65937,containing 187 virulence genes and 97 drug resistance genes,with high sequence similarity(95.16%~100.00%)to the main virulence factor-encoding genes in the Virulence Factor Database.Compared with the strains of ATCC 19615 and GAS029,the strain 21SPY7071 showed reduced expression of genes encoding streptolysin S(sagABCDEFGHI),streptolysin O(slo),and hyaluronate lyase(endA/sdaB).Besides,compared with the strain ATCC 19615,the strain 21SPY7071 also showed decreased expression of virulence genes including speG,ideS/mac,hylA,smeZ,lmb,and scpA/scpB.ConclusionThis Streptococcus pyogenes strain isolated from the pus of a child with atypical brain abscess exhibits weak hemolysis and lower expression of virulence genes,which may be related to the mild clinical symptoms observed in the child.

关 键 词：化脓链球菌 全基因组测序 毒力因子 

分 类 号：R446.5[医药卫生—诊断学]