Contribution of cell surface protein antigen PAc of Streptococcus mutans to bacteremia
Contribution of cell surface protein antigen PAc of Streptococcus mutans to bacteremia
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DOI：
10.1016/j.micinf.2005.06.005
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发表时间：
2006-01-01
影响因子：
5.8
通讯作者：
Ooshima, T
中科院分区：
文献类型：
--
作者：
Nakano, K;Tsuji, M;Ooshima, T
变形链球菌是一种主要的致龋细菌，偶尔从菌血症和感染性心内膜炎患者的血液中分离出来。用耐药盒插入灭活各基因，构建了主要表面蛋白葡萄糖基转移酶（GTF） B-、C-、D-和蛋白抗原C （PAc）缺陷的变形链球菌MT8148突变株。通过分析细菌与人多形核白细胞的相互作用来确定对吞噬的敏感性，pac缺陷突变株（PD）的吞噬率最低。另外，将PD和MT8148分别注射到Sprague-Dawley大鼠颈静脉时，PD的恢复数量明显多于MT8148，恢复持续时间明显长于MT8148，引起的全身炎症反应更为严重，说明变形链球菌PAc与其血液中的全身毒力有关。接下来，采用Western blotting方法，对来自100名日本儿童和青少年的100株S. mutans临床分离株进行分析，使用基于MT8148的PAc序列生成的重组PAc抗血清。100株菌株中有4株无阳性带，其吞噬率均显著低于随机选取的25株临床菌株（P < 0.01）。此外，100株菌株中有3株的PAc分子量较低，吞噬率显著低于25株对照菌株（P < 0.05）。这些结果表明，变形链球菌PAc可能与人类多形核白细胞的吞噬敏感性有关，大约7%的变形链球菌临床分离株可能是发生菌血症的高危株。(c) 2005 Elsevier SAS。版权所有。
Streptococcus mutans, a major cariogenic bacterium, is occasionally isolated from the blood of patients with bacteremia and infective endocarditis. Mutant strains of S. mutans MT8148, defective in the major surface proteins glucosyltransferase (GTF) B-, C-, and D-, and protein antigen c (PAc), were constructed by insertional inactivation of each respective gene with an antibiotic resistant cassette. Susceptibility to phagocytosis was determined by analyses of interactions of the bacteria with human polymorphonuclear leukocytes, and the PAc-defective mutant strain (PD) showed the lowest rate of phagocytosis. Further, when PD and MT8148 were separately injected into the jugular veins of Sprague-Dawley rats, PD was recovered in significantly larger numbers and for a longer duration, and caused more severe systemic inflammation than MT8148, indicating that S. mutans PAc is associated with its systemic virulence in blood. Next, 100 S. mutans clinical isolates from 100 Japanese children and adolescents were analyzed by Western blotting using antisera raised against recombinant PAc, generated based on the pac sequence of MT8148. Four of the 100 strains showed no positive band and each exhibited a significantly lower phagocytosis rate than that of 25 randomly selected clinical strains (P < 0.01). In addition, three of the 100 strains possessed a lower molecular weight PAc and a significantly lower rate of phagocytosis than the 25 reference strains (P < 0.05). These results suggest that S. mutans PAc may be associated with phagocytosis susceptibility to human polymorphonuclear leukocytes, with approximately 7% of S. mutans clinical isolates possible high-risk strains for the development of bacteremia. (c) 2005 Elsevier SAS. All rights reserved.