來自凱斯西部保留地大學(xué)和耶魯大學(xué)的科學(xué)家在理解為何一些孕婦的子宮內(nèi)部會(huì)遭遇無任何感染跡象的炎癥問題上有了顯著的進(jìn)展,。
利用基因克隆技術(shù),，科學(xué)家發(fā)現(xiàn)存在于患羊膜內(nèi)炎癥的婦女體內(nèi)的大約60%的細(xì)菌被傳統(tǒng)的培養(yǎng)測(cè)試漏掉了,，后者被認(rèn)為是發(fā)現(xiàn)細(xì)菌感染的金標(biāo)準(zhǔn),。
這些發(fā)現(xiàn)發(fā)表在了《臨床微生物學(xué)雜志》1月號(hào)上,。
這組科學(xué)家利用新的DNA方法追蹤細(xì)菌的存在,，從而首次發(fā)現(xiàn)了羊膜內(nèi)感染的微生物物種的一份詳盡名單,。為了增加準(zhǔn)確性,，這組科學(xué)家使用了多種分析手段的綜合,，包括羊水的蛋白質(zhì)組學(xué)結(jié)果以及對(duì)胎盤的組織學(xué)分析，從而證實(shí)這種感染和炎癥,。
凱斯西部保留地大學(xué)的牙科醫(yī)學(xué)副教授,、該研究的主要作者Yiping Han說，羊膜內(nèi)炎癥已知會(huì)導(dǎo)致不到32周的胎兒的自發(fā)早產(chǎn),。該研究對(duì)46名婦女進(jìn)行了研究,，其中44名婦女經(jīng)歷過早產(chǎn)。Han 此前進(jìn)行了多個(gè)研究項(xiàng)目,，檢查了口腔細(xì)菌和早產(chǎn)之間的聯(lián)系,。
在這項(xiàng)研究中，科學(xué)家對(duì)來自有早產(chǎn)體征或癥狀的懷孕婦女的羊水細(xì)菌濃度和對(duì)照組的沒有這類跡象且足月分娩的16名婦女的羊水細(xì)菌濃度進(jìn)行了比較,。對(duì)照組的羊水來自用于遺傳篩查的羊水穿刺或者檢查胎兒肺部成熟的分析,，甚至DNA方法也沒有顯示出其中有細(xì)菌的跡象。
“由于培養(yǎng)沒有發(fā)現(xiàn)羊水中的全部細(xì)菌,，這要求使用新的檢測(cè)方法,，”Han說。“同樣重要的是發(fā)現(xiàn)哪種細(xì)菌造成了導(dǎo)致早產(chǎn)的感染和炎癥，從而在這個(gè)病理生理學(xué)連鎖事件的早期使用抗生素,。”
利用新的檢測(cè)過程——該過程為了識(shí)別16SrRNA細(xì)菌基因序列,，擴(kuò)增了該基因并把它克隆——除了可以發(fā)現(xiàn)細(xì)菌培養(yǎng)能發(fā)現(xiàn)的細(xì)菌，這組科學(xué)家還有能力發(fā)現(xiàn)一些細(xì)菌培養(yǎng)無法發(fā)現(xiàn)的有害細(xì)菌,，其中一些細(xì)菌此前沒有和早產(chǎn)聯(lián)系起來,。
“通過利用基于16s rRNA基因的聚合酶鏈?zhǔn)椒磻?yīng)（PCR）和之后的克隆分析，我們可以確定羊膜內(nèi)細(xì)菌感染和早產(chǎn)發(fā)作之間的特征和真正的關(guān)系,，”Han說,。
這組科學(xué)家還發(fā)現(xiàn)不僅僅是樣本中的一種細(xì)菌導(dǎo)致了炎癥，而是大量的不同種類的細(xì)菌,，“未被發(fā)現(xiàn)的,、無法培養(yǎng)的或很難培養(yǎng)的細(xì)菌物種可能在導(dǎo)致自發(fā)早產(chǎn)方面扮演了一個(gè)關(guān)鍵的角色，”Han說,。
這些細(xì)菌或者通過生殖道到達(dá)胎盤,，或者通過血液到達(dá)胎盤。Han懷疑其中一些細(xì)菌源于口腔,，口腔中存在成百上千種細(xì)菌,。這些口腔細(xì)菌中的一種是具核梭桿菌（Fusobacterium nucleatum ）,，它在口腔中普遍存在,。然而，一旦它進(jìn)入了血流中,，它就和一些健康問題有了關(guān)聯(lián),。（生物谷Bioon.com）
生物谷推薦原始出處：
Journal of Clinical Microbiology, January 2009, p. 38-47, Vol. 47, No. 1
Uncultivated Bacteria as Etiologic Agents of Intra-Amniotic Inflammation Leading to Preterm Birth
Yiping W. Han,1,2* Tao Shen,1 Peter Chung,1 Irina A. Buhimschi,3 and Catalin S. Buhimschi3
Department of Periodontics, Case Western Reserve University School of Dental Medicine, Cleveland, Ohio 44106,1 Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106,2 Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University, New Haven, Connecticut 065203
Intra-amniotic infection and inflammation are major causes of preterm birth (PTB). However, intra-amniotic inflammation is often detected in the absence of infection. This may partly be due to the culturing methods employed in hospital laboratories, which are unable to detect the uncultivated species. In this study, intra-amniotic microbial infections associated with PTB were examined by both culture and 16S rRNA-based culture-independent methods and were corroborated by the presence of intra-amniotic inflammation. Amniotic fluid (AF) specimens from 46 pregnancies complicated by PTB and 16 asymptomatic women were analyzed. No bacterial DNA was amplified in AF collected from the asymptomatic women. Among the 46 samples associated with PTB, bacterial DNA was amplified from all (16/16) of the culture-positive samples and 17% (5/30) of the culture-negative samples. In the culture-positive group, additional species were detected in more than half (9/16) of the cases by PCR and clone analysis. Altogether, approximately two- thirds of the species detected by the culture-independent methods were not isolated by culture. They included both uncultivated and difficult-to-cultivate species, such as Fusobacterium nucleatum, Leptotrichia (Sneathia) spp., a Bergeyella sp., a Peptostreptococcus sp., Bacteroides spp., and a species of the order Clostridiales. To examine intra-amniotic inflammation, an AF proteomic fingerprint (mass-restricted score) was determined by surface-enhanced laser desorption ionization-time-of-flight mass spectrometry. Inflammation was detected in all five samples which were culture negative but PCR positive. Women who were PCR positive more often had elevated interleukin-6 levels in their AF, histological chorioamnionitis, and funisitis and delivered neonates with early-onset neonatal sepsis. Previously unrecognized, uncultivated, or difficult-to-cultivate species may play a key role in the initiation of PTB.
