Yamanaka Takeshi, Furukawa Tomoyo, Matsumoto-Mashimo Chiho, Yamane Kazuyoshi, Sugimori Chieko, Nambu Takayuki, Mori Naoki, Nishikawa Hiroyuki, Walker Clay B, Leung Kai-Poon, Fukushima Hisanori
Department of Bacteriology, Osaka Dental University, Osaka, Japan.
BMC Microbiol. 2009 Jan 16;9:11. doi: 10.1186/1471-2180-9-11.
Prevotella intermedia (P. intermedia), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. P. intermedia strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials in vitro from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays.
Strain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (sigmaE; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media.
These results demonstrate that the capacity to form biofilm in P. intermedia contribute to their resistance against host innate defence responses.
中间普氏菌是一种革兰氏阴性、产黑色色素的厌氧杆菌，与慢性口腔感染的发生有关。中间普氏菌17株是从我们实验室的慢性牙周炎病变中分离出来的，被描述为一种产生粘性物质的菌株。该菌株的保藏培养物仍保持在陈旧培养基中产生大量粘性物质并形成生物膜样结构的能力。对这种粘性物质的化学分析表明，它们主要由中性糖组成，其中甘露糖占多糖的83%。为了研究细胞外粘性物质的生物学效应，我们从菌株17的保藏培养物中鉴定并获得了一种自然发生的变异菌株，该菌株在体外缺乏产生粘性物质的能力，命名为17-2。我们比较了这两种菌株（17株与17-2株）形成生物膜的能力以及在小鼠体内诱导脓肿形成的能力，以此作为它们致病性的指标。此外，还使用微阵列分析比较了这两种菌株在浮游状态下的基因表达谱以及菌株17在固体和液体培养中的基因表达模式。
与变异株相比，17株在小鼠体内诱导形成的脓肿更大。17株能够干扰人中性粒细胞的吞噬活性，而17-2株则不能。与变异菌株17-2相比，包括热休克蛋白（DnaJ、DnaK、ClpB、GroEL和GroES）相关基因在内的几个基因在形成生物膜的17株中的表达上调了两到四倍，具有统计学意义。与在液体培养基中的17株相比，在固体培养条件下的17株中，包括果聚糖酶、胞外功能亚家族σ因子（σE；推测）和多聚唾液酸转运蛋白（KpsD）相关基因在内的几个基因的表达水平上调了八倍以上。
这些结果表明，中间普氏菌形成生物膜的能力有助于其抵抗宿主的固有防御反应。
