Biofilms formed by nontypeable Haemophilus influenzae in vivo contain both double-stranded DNA and type IV pilin protein
Biofilms formed by nontypeable Haemophilus influenzae in vivo contain both double-stranded DNA and type IV pilin protein
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DOI：
10.1128/jb.01935-06
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发表时间：
2007-05-01
影响因子：
3.2
通讯作者：
Bakaletz, Lauren O.
中科院分区：
文献类型：
--
作者：
Jurcisek, Joseph A.;Bakaletz, Lauren O.
不可分型流感嗜血杆菌（NTHI）菌株是正常人类鼻咽菌群的成员，也是上呼吸道和下呼吸道常见的机会性病原体。最近，研究表明NTHI在体内和体外都能形成生物膜。在体外形成的生物膜内，NTHI菌株分别表达低脂寡糖（LOS）和外膜蛋白P2、P5和P6的表位，而在体外96孔板试验或哺乳动物宿主中产生的菌株已被证明在生物膜基质中含有唾液化的低脂寡糖的特定糖型。虽然DNA已被确定为几种细菌病原体在体外形成的生物膜基质的关键成分，但在这里，我们首次证明，除了唾液化的LOS外，NTHI在体内形成的生物膜还含有IV型pilin蛋白和大量的双链DNA。DNA似乎排列在一个密集的细链交错的网络中，也排列在跨越水道的单个更粗的“绳”中，这表明DNA可能赋予NTHI在体内产生的生物膜结构稳定性。IV型菌毛蛋白的存在在生物膜基质中以小聚集体的形式出现，并沿着DNA链追踪，这支持了我们的观察结果，即当这些细菌在中耳空间形成生物膜时，实验性中耳炎介质中NTHI表达了IV型菌毛。
Nontypeable Haemophilus influenzae (NTHI) strains are members of the normal human nasopharyngeal flora, as well as frequent opportunistic pathogens of both the upper and lower respiratory tracts. Recently, it has been shown that NTHI can form biofilms both in vitro and in vivo. NTHI strains within in vitro-formed biofilms differentially express both epitopes of lipooligosaccharide (LOS) and the outer membrane proteins P2, P5, and P6, whereas those generated either in a 96-well plate assay in vitro or in a mammalian host have been shown to incorporate a specific glycoform of sialylated LOS within the biofilm matrix. While DNA has been identified as a key component of the biofilm matrix formed in vitro by several bacterial pathogens, here we demonstrate for the first time that in addition to sialylated LOS, the biofilm formed by NTHI in vivo contains both type IV pilin protein and a significant amount of double-stranded DNA. The DNA appeared to be arranged in a dense interlaced meshwork of fine strands as well as in individual thicker "ropes" that span water channels, suggesting that DNA could be imparting structural stability to the biofilm produced by NTHI in vivo. The presence of type IV pilin protein both appearing as small aggregates within the biofilm matrix and tracking along DNA strands supports our observations which showed that type IV pili are expressed by NTHI during experimental otitis media when these bacteria form a biofilm in the middle ear space.