AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diar...AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diarrhea patients.METHODS: The distribution of 12 HPI genes was investigated by PCR and DNA hybridization in two prototype strains of EAggEC, EAggEC 17-2, EAggEC O42, and 6 clinical EAggEC isolates from China. The production of siderophore Ybt in HPI-positive strains was detected by reporter gene bioassay to determine the relation between HPI genes and expression of Ybt. Flow cytometry was used to detect fluorescent signal of the reporter strain that could designate production of Ybt.RESULTS: Seven strains were HPI-positive and one strain was HPI-negative. Six of the seven HPI-positive strains were inserted into asnT-tRNA site. Moreover, seven EAggEC HPI-positive strains revealed enhanced fluorescence signal but the EAggEC HPI-negative strain did not. However, there was a difference in Ybt expression condition and level among these seven EAggEC HPI-positive strains. Although UFT073 strain, the prototype strain of uropathogenic E.coli(UPEC), carried the complete HPI core part, we did not detect the expression of Ybt in it.CONCLUSION: EAggEC HPI-positive strains can express the Ybt system, but the presence of HPI core part does not mean the functional expression of Ybt.展开更多
目的调查医院不同标本分离大肠埃希菌P菌毛基因分型,探究基因分型与标本来源之间的关系。方法收集2009年1-12月温州医学院附属第二医院分离大肠埃希菌120株,采用Microscan Walk away 96SI微生物鉴定仪进行鉴定和药敏试验,按CLSI 2009年...目的调查医院不同标本分离大肠埃希菌P菌毛基因分型,探究基因分型与标本来源之间的关系。方法收集2009年1-12月温州医学院附属第二医院分离大肠埃希菌120株,采用Microscan Walk away 96SI微生物鉴定仪进行鉴定和药敏试验,按CLSI 2009年标准判定;用PCR法检测P菌毛和I型菌毛基因;采用χ2检验,P<0.05为差异有统计学意义。结果 papC基因阳性率为39.19%,其中尿液分离株阳性率为54.50%,显著高于痰液、引流液以及脓液分离株(P<0.05);papG分型率为64.20%,papGⅡ型检出率为46.67%,其中尿液分离株阳性率为70.54%,显著高于痰液和血液分离株(P<0.05);papGⅢ型检出率为17.50%,其中尿液分离株阳性率为25.00%,显著高于痰液分离株(P<0.05);未检测出papGⅠ型。结论不同标本分离大肠埃希菌papC基因携带率不同,尿液中肾盂肾炎大肠埃希菌(UPEC)的分离率最高,papG分型以papGⅡ型为主,存在部分papGⅢ型。展开更多
基金Supported by the National Basic Research Program of Ministry of Science and Technology of China, No. G1999054101
文摘AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diarrhea patients.METHODS: The distribution of 12 HPI genes was investigated by PCR and DNA hybridization in two prototype strains of EAggEC, EAggEC 17-2, EAggEC O42, and 6 clinical EAggEC isolates from China. The production of siderophore Ybt in HPI-positive strains was detected by reporter gene bioassay to determine the relation between HPI genes and expression of Ybt. Flow cytometry was used to detect fluorescent signal of the reporter strain that could designate production of Ybt.RESULTS: Seven strains were HPI-positive and one strain was HPI-negative. Six of the seven HPI-positive strains were inserted into asnT-tRNA site. Moreover, seven EAggEC HPI-positive strains revealed enhanced fluorescence signal but the EAggEC HPI-negative strain did not. However, there was a difference in Ybt expression condition and level among these seven EAggEC HPI-positive strains. Although UFT073 strain, the prototype strain of uropathogenic E.coli(UPEC), carried the complete HPI core part, we did not detect the expression of Ybt in it.CONCLUSION: EAggEC HPI-positive strains can express the Ybt system, but the presence of HPI core part does not mean the functional expression of Ybt.
