Role of Colonization in the Virulence of Actinomyces viscosus Strains T14-Vi and T14-Av
Role of Colonization in the Virulence of Actinomyces viscosus Strains T14-Vi and T14-Av
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定植在粘性放线菌菌株 T14-Vi 和 T14-Av 毒力中的作用
DOI：
10.1128/iai.22.2.603-614.1978
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发表时间：
1978
影响因子：
3.1
通讯作者：
B. F. Hammond
中科院分区：
文献类型：
--
作者：
S. Brecher;J. van Houte;B. F. Hammond
用粘性放线菌菌株T14-Vi（毒性）或T14-Av（无毒力）接种喂食高蔗糖饮食的无菌大鼠。从90天后处死的大鼠的6个提取的精细研磨的磨牙中，菌株T14-Vi的平均回收率为1.1 × 108菌落形成单位（CFU）。T14-Av的平均回收率为5.7 × 107 CFU，明显低于T14-Vi，T14-Vi引起严重的牙槽骨丢失，而T14-Av感染的大鼠仅出现轻微的骨丢失。无菌大鼠牙齿的扫描电子显微镜显示，菌株T14-Vi定植在裂缝以及牙龈附近的牙齿表面区域;菌株T14-Av也定植在裂缝中，但无法定植在牙龈附近的牙齿。在对喂食高糖饮食的常规大鼠的研究中，链霉素抗性菌株T14-Vi在接种了108或107 CFU数量级的所有大鼠的牙齿上以及在接种了106或105 CFU的约一半大鼠的牙齿上定殖。相反，链霉素抗性菌株T14-Av在类似接种的组中的任何大鼠的牙齿上都不能检测到。在体外“休息”细胞的两个菌株悬浮在常规或无菌大鼠唾液中存活到相当的程度。[3 H]胸腺嘧啶标记的T14-Vi细胞与羟基磷灰石（HA）珠和用无菌或常规大鼠唾液预处理的HA珠粘附良好。相反，T14-Av细胞粘附不如T14-Vi细胞粘附HA，而它们粘附唾液包被的HA是可以忽略不计的。负染色的T14-Vi和T14-Av细胞在1%磷钨酸中反复通过的透射电子显微镜显示两种菌株的细胞上的纤维。T14-Av细胞被大量的细胞外物质所覆盖，这可能是杂多糖; T14-Vi细胞表面上存在很少的细胞外物质。T14-Vi细胞对菌株T14-Av合成的杂多糖具有相对较低的亲和力。其他证据也表明，这种多糖对唾液包被的HA具有相对较低的亲和力。总的来说，证据表明菌株T14-Vi和T14-Av之间牙周病变潜力的差异是由于它们在牙齿上定植的能力不同。这种差异可能是由于T14-Av细胞对牙齿的粘附性较低，而不是它们在口腔中生长的能力。T14-Av细胞对牙齿表面的低亲和力可能部分归因于大量细胞表面相关多糖的存在。
Germfree rats fed a high-sucrose diet were inoculated with Actinomyces viscosus strain T14-Vi (virulent) or T14-Av (avirulent). The mean recovery of strain T14-Vi from six extracted finely ground molars of rats sacrificed after 90 days was 1.1 × 108 colony-forming units (CFU). The mean recovery of strain T14-Av was 5.7 × 107 CFU, which was significantly less. Strain T14-Vi caused severe alveolar bone loss, but only minimal bone loss occurred in rats infected with strain T14-Av. Scanning electron microscopy of teeth of germfree rats revealed that strain T14-Vi colonized in the fissures as well as on tooth surface areas near the gingiva; strain T14-Av also colonized in fissures but was unable to colonize the teeth near the gingiva. In studies with conventional rats fed a high-sucrose diet, streptomycin-resistant strain T14-Vi colonized on the teeth of all rats inoculated with in the order of 108 or 107 CFU and on the teeth of about half of the rats inoculated with 106 or 105 CFU. In contrast, streptomycin-resistant strain T14-Av could not be detected on the teeth of any of the rats in groups similarly inoculated. In vitro “resting” cells of both strains suspended in conventional or germfree rat saliva survived to comparable degrees. [3H]thymidine-labeled T14-Vi cells adhered well to hydroxyapatite (HA) beads and to HA beads pretreated with saliva obtained from germfree or conventional rats. In contrast, T14-Av cells adhered less well than did T14-Vi cells to HA, whereas their adherence to saliva-coated HA was negligible. Transmission electron microscopy of negatively stained T14-Vi and T14-Av cells repeatedly passed in 1% phosphotungstic acid revealed fibrils on cells of both strains. T14-Av cells were covered by large amounts of extracellular material which was presumably heteropolysaccharide; little extracellular material was present on the surface of T14-Vi cells. T14-Vi cells had a relatively low affinity for the heteropolysaccharide synthesized by strain T14-Av. Other evidence also suggested that this polysaccharide had a relatively low affinity for saliva-coated HA. Collectively, the evidence indicates that the difference in periodontopathic potential between strains T14-Vi and T14-Av results from their different abilities to colonize teeth. This difference is probably due to the lower adherence of T14-Av cells to teeth rather than to their ability to grow in the mouth. The low affinity of T14-Av cells for tooth surfaces may be due, in part, to the presence of large amounts of cell-surface-associated polysaccharide.