念珠菌血症中白假丝酵母的分子流行病学研究
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摘要
目的探讨念珠菌血症中白假丝酵母的基因分型,了解其流行病学特征。方法收集患者血培养阳性,经科玛嘉显色培养基进行菌株的初步筛选;用扩增真菌的转录间隔间区(ITS区)和核糖体大亚基(26rRNA、D1/D2区)、基因测序对初筛的菌株进行标准的分子生物学鉴定;利用白假丝酵母的七对管家基因多位点序列分型,利用软件分析其亲缘关系。结果各管家基因的等位基因的同一位点可出现多次碱基变异;在管家基因中ACC1基因的碱基变异位点最少,仅4个,而SYA1基因的碱基变异位点最多;16株白假丝酵母可分为10个群,其中一个群由5个菌株构成,2个群都是由2个菌株构成,其他的群都是由一个菌株单独构成。结论白假丝酵母的二倍体序列型都为新发的基因型,未发现流行的克隆株。
OBJECTIVE To investigate the Candida albicans genotypes in candidal bacteremia and understand its epidemiological characteristics.METHODS The positive blood cultures were collected and the primary screening of strains was carried out by using Komaga chromogenic medium.The primary screening strains were subjected to standard molecular biological identification by amplifying the transcribed intergenic(ITS)region of the fungus and the large ribosomal subunit(26 rRNA,D1/D2 region)and gene sequencing.Multilocus sequence typing was carried out by using seven pairs of housekeeping genes of C.albicans,and the genetic relationship was analyzed by software.RESULTS There may be multiple base variations at the same site of the butler gene alleles.Among the housekeeping genes,ACC1 gene has the least number of base mutation sites,only 4,while SYA1 gene has the largest number of base variation sites.16 strains of C.albicans can be divided into 10 groups,1 of which consists of5 strains,2 are composed of 2 strains,and others are composed of a single strain.CONCLUSIONAll of the diploid sequences of C.albicans are novel genotypes.No epidemic clones are found.
OBJECTIVE To investigate the Candida albicans genotypes in candidal bacteremia and understand its epidemiological characteristics.METHODS The positive blood cultures were collected and the primary screening of strains was carried out by using Komaga chromogenic medium.The primary screening strains were subjected to standard molecular biological identification by amplifying the transcribed intergenic(ITS)region of the fungus and the large ribosomal subunit(26 rRNA,D1/D2 region)and gene sequencing.Multilocus sequence typing was carried out by using seven pairs of housekeeping genes of C.albicans,and the genetic relationship was analyzed by software.RESULTS There may be multiple base variations at the same site of the butler gene alleles.Among the housekeeping genes,ACC1 gene has the least number of base mutation sites,only 4,while SYA1 gene has the largest number of base variation sites.16 strains of C.albicans can be divided into 10 groups,1 of which consists of5 strains,2 are composed of 2 strains,and others are composed of a single strain.CONCLUSIONAll of the diploid sequences of C.albicans are novel genotypes.No epidemic clones are found.
引文
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[2]刘怡雯,詹燏,胡枫,等.ICU患者感染念珠菌的临床分布及体外药敏分析[J].中华医院感染学杂志,2016,26(20):4602-4604.
[3]凌勇,侯铁英,陈柳勤,等.250例真菌性血流感染的临床特点分析[J].中华医院感染学杂志,2016,26(21):4876-4878.
[4]李秀萍,王玉清,程国栋,等.肺结核患者真菌感染的临床特点及耐药性分析[J].中华医院感染学杂志,2016,26(14):3141-3143.
[5]李丁,张青,白长森,等.肿瘤患者合并非白念珠菌性血流感染的危险因素分析[J].中华医院感染学杂志,2017,27(6):1240-1243.
[6]Wisplinghoff H,Ebbers J,Geurtz L,et al.Nosocomial bloodstream infections due to Candida spp.in the USA:species distribution,clinical features and antifungal susceptibilities[J].Int J Antimicrob Agents,2014,43(1):78-81.
[7]Wang H,Xu YC,Hsueh PR.Epidemiology of candidemia and antifungal susceptibility in invasive Candida species in the Asia-Pacific region[J].Future Microbiol,2016,11:1461-1477.
[8]Saghrouni F,Ben Abdeljelil J,Boukadida J,et al.Molecular methods for strain typing of Candida albicans:a review[J].J Appl Microbiol,2013,114(6):1559-1574.
[9]Maiden MC.Multilocus sequence typing of bacteria[J].Annu Rev Microbiol,2006,60:561-588.
[10]Wang Y,Shi C,Liu JY,et al.Multilocus sequence typing of Candida tropicalis shows clonal cluster enrichment in azoleresistant isolates from patients in Shanghai,China[J].Infect Genet Evol,2016,44:418-424.