【摘要】 目的探讨表皮葡萄球菌临床株中ica操纵子转录水平对生物膜表型差异的影响。方法采用微量板半定量法检测细菌生物膜表型,用Southern杂交和聚合酶链反应检测icaA基因及ica操纵子中是否存在插入序列,用RNA狭缝杂交和逆转录实时定量聚合酶链反应检测icaA基因和icaR基因的转录水平;采用χ2检验分析icaA基因与生物膜表型的相关性,采用单因素方差检验分析转录水平的差异。结果101株临床分离株中,32.7%(33/101株)能形成生物膜,其中22株icaA基因阳性;67.3%(68/101株)无生物膜形成,其中15株icaA基因阳性。15株icaA+/生物膜表型-分离株中,ica操纵子各基因中均不存在插入序列,icaA基因的转录水平明显低于生物膜阳性的ATCC35984株(P<0.05),其中2株icaR基因的转录水平高于ATCC35984株(P<0.01)。结论表皮葡萄球菌临床株中ica操纵子的存在与生物膜表型相关(χ2=19.045,P<0.01);ica操纵子的低转录是icaA+/生物膜表型-临床株不形成生物膜的主要原因。更多还原

【Abstract】 Objective To illuminate the influence of ica operon transcription on clinical staphylococcus epidermidis biofilm phenotype. Methods Microtiter-test was performed to semi-quantify biofilm phenotype, Southern Blot and PCR were performed to detect ica genes and insertion, as well as RNA Slot and RT- Real-time PCR were used to evaluate the transcription level of icaA and icaR. The significance of the relationship between icaA and biofilm was evaluated by χ2 test and significant difference of transcription was tested by a one-way analysis of variance(ANOVA). Results 32.7%(33/101) isolates were biofilm-positive among which 22 isolates were icaA- positive, and 67.3%(68/101) failed to form biofilm among which 15 isolates were icaA-positive. No insertion was found in ica genes among the 15 icaA-positive/ biofilm-negative isolates, and transcriptions of icaA were all dramatically slower compared to ATCC35984(P<0.05). Furthermore, transcription of icaR was higher than ATCC35984 in 2 icaA-positive/ biofilm-negative isolates(P<0.01). Conclusions icaA gene is closely related to biofilm phenotype in 101 clinical staphylococcus epidermidis isolates. And low transcriptions of ica operon are responsible for nonbiofilm phenotype in icaA-positive/ biofilm-negative isolates.更多还原