本文選題：尿路致病性大腸埃希菌 + I型菌毛�。� 參考：《天津醫(yī)科大學(xué)》2017年碩士論文

【摘要】：目的尿路致病性大腸埃希菌(UPEC)是引起尿路感染的主要致病菌。黏附素被認(rèn)為是UPEC最重要的毒力因子,主要包括I型菌毛、P型菌毛、S型菌毛、FIC菌毛和Afa/Dr菌毛等。I型菌毛最常見,而fimH基因編碼的I型菌毛頂端fimH蛋白粘附于人尿道上皮細(xì)胞,是引發(fā)尿路感染的關(guān)鍵環(huán)節(jié);P型菌毛同樣廣泛存在,被認(rèn)為是UPEC在感染尿道后繼續(xù)上行至腎臟引起腎盂腎炎的關(guān)鍵因子。本文旨在研究不同耐藥程度的UPEC臨床分離株I型菌毛及P型菌毛相關(guān)菌毛基因fimA、fim B、fimH、papA、papB、papC、papGII在基因水平、轉(zhuǎn)錄水平及粘附水平存在的差異,分析其原因,并初步探討耐藥情況與黏附功能的關(guān)系,從而提高粘附阻斷性治療的精確度。方法收集2012年3月至2015年10月天津地區(qū)四家三級(jí)甲等醫(yī)院(天津醫(yī)科大學(xué)第二醫(yī)院、天津市一中心醫(yī)院、天津市兒童醫(yī)院、天津醫(yī)科大學(xué)總醫(yī)院)非植入導(dǎo)尿管患者尿液樣本分離的非重復(fù)感染大腸埃希菌。菌株采用法國生物梅里埃公司VitekⅡ系統(tǒng)鑒定,配套革蘭陰性桿菌藥敏卡片進(jìn)行體外藥敏試驗(yàn),篩選出多重耐藥菌株和非多重耐藥菌株。將UPEC分為敏感組(非多重耐藥菌株)和耐藥組(多重耐藥菌株),每組菌株50株,共100株。通過PCR方法進(jìn)行基因片段擴(kuò)增,然后通過瓊脂糖凝膠電泳的方式判斷毒力因子基因的檢出情況;針對(duì)不同耐藥程度單個(gè)毒力因子基因檢出陽性的菌株進(jìn)行熒光定量PCR檢測(cè)毒力因子基因的相對(duì)表達(dá)量;UPEC表達(dá)I型菌毛的能力通過與酵母細(xì)胞的黏附實(shí)驗(yàn)來檢測(cè),表達(dá)P型菌毛的能力通過與人A型紅細(xì)胞的凝血實(shí)驗(yàn)來檢測(cè),通過酵母細(xì)胞及紅細(xì)胞凝集試驗(yàn)分別檢測(cè)I型菌毛及P菌毛的粘附情況。兩組之間的比較采用卡方檢驗(yàn)和t檢驗(yàn)。結(jié)果UPEC I型菌毛和P型菌毛通過基因片段擴(kuò)增,毒力基因fimH、fimA、fimB、papGII、papA、papB、papC在敏感組中的檢出率分別為90%、48%、76%、16%、26%、64%、32%,在耐藥組中的檢出率為84%、46%、58%、42%、36%、56%、38%。fimH基因在敏感組和耐藥組的檢出率都處于高水平。papGII基因在敏感組中的檢出率明顯高于耐藥組(χ~2=8.208,P0.05),而其他基因在兩組間的檢出率差異無統(tǒng)計(jì)學(xué)意義(P0.05)。Rt-PCR結(jié)果表明敏感組毒力因子基因fimH、fimB、papC表達(dá)量高于耐藥組;粘附實(shí)驗(yàn)表明敏感組菌株I型菌毛的黏附能力高于耐藥組(χ~2=5.769,P0.05),P型菌毛的黏附能力在兩組間沒有區(qū)別(χ~2=2.439,P0.05)。結(jié)論UPEC毒力因子基因fimH無論是在敏感組還是耐藥組菌株都存在廣泛的流傳性;UPEC敏感組菌株I型菌毛的粘附能力高于耐藥組,推測(cè)與耐藥菌的適應(yīng)性代價(jià)有關(guān);UPEC粘附功能除受fimH基因及papGII基因這些關(guān)鍵因素影響外,fim及pap基因簇編碼的其他基因的缺失和轉(zhuǎn)錄也會(huì)對(duì)I型菌毛及P型菌毛的黏附功能產(chǎn)生影響。
[Abstract]:Objective Urethropathogenicity Escherichia coli (UPEC) is the main pathogen causing urinary tract infection. Adhesion factor is considered to be the most important virulence factor of UPEC, mainly including type I pili, type S pili and Afa/Dr pili. FimH protein at the tip of type I pili encoded by fimH gene adheres to human urethral epithelial cells. It is the key link of urinary tract infection that P type pili also exists widely, which is considered to be the key factor that UPEC continues to uplink to the kidney to cause pyelonephritis after infection of urethra. The purpose of this study was to study the differences in gene level, transcription level and adhesion level between type I and P type pili genes of UPEC clinical isolates with different degrees of drug resistance, and analyze the reasons for the differences in gene level, transcriptional level and adhesion level. The relationship between drug resistance and adhesion function was discussed in order to improve the accuracy of adhesion blocking therapy. Methods from March 2012 to October 2015, four Grade 3A hospitals (the second Hospital of Tianjin Medical University, the first Central Hospital of Tianjin, the Children's Hospital of Tianjin) were collected. Urine samples from patients with non-implanted catheter were isolated from non-repeated infection Escherichia coli. The strains were identified by Vitek 鈪，

本文編號(hào)：1795260