Husmann L K, Dillehay D L, Jennings V M, Scott J R
Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322, USA.
Microb Pathog. 1996 Apr;20(4):213-24. doi: 10.1006/mpat.1996.0020.
We inoculated 5 to 7-week-old female C3HeB/FeJ mice with Streptococcus pyogenes strain B514-Sm (type M50) by both an intranasal and intratracheal route and characterized the resulting illness. Following intranasal inoculation, the animals developed signs of illness within 1 to 8 days post-inoculation which correlated with acute, suppurative, bronchopneumonia during histopathologic analysis; however, the relationship of response to dose was non-linear, as seen previously in a small group of mice. Intratracheal inoculations were then performed to increase the quantitative reliability of the model. Following intratracheal inoculation, the animals succumbed to an illness that was indistinguishable from that seen after intranasal inoculation, and the incidence of pneumonia followed a steep dose response curve. The dose at which 50% of the animals exhibited signs of respiratory illness within 72 h was 1.0 x 10(7) colony forming units. All of the animals that appeared ill had lung lesions as determined by gross and histopathologic examination. Bacteraemia followed pneumonia in two-thirds of the intratracheally inoculated animals, indicating that the S. pyogenes had crossed tissue barriers. We hope that this model will be useful in future studies concerning the role of suspected streptococcal virulence factors in the later stages of pathogenesis of invasive S. pyogenes infection.
我们通过鼻内和气管内途径用化脓性链球菌B514-Sm菌株（M50型）接种5至7周龄雌性C3HeB/FeJ小鼠，并对由此引发的疾病进行了表征。鼻内接种后，动物在接种后1至8天内出现疾病迹象，这与组织病理学分析中的急性化脓性支气管肺炎相关；然而，正如之前在一小群小鼠中所观察到的，反应与剂量的关系是非线性的。随后进行气管内接种以提高模型的定量可靠性。气管内接种后，动物死于与鼻内接种后所见疾病无法区分的疾病，肺炎发病率遵循陡峭的剂量反应曲线。在72小时内50%的动物出现呼吸道疾病迹象的剂量为1.0×10⁷菌落形成单位。通过大体和组织病理学检查确定，所有出现疾病的动物都有肺部病变。三分之二气管内接种的动物在肺炎后出现菌血症，这表明化脓性链球菌已突破组织屏障。我们希望这个模型将有助于未来关于疑似链球菌毒力因子在侵袭性化脓性链球菌感染发病后期作用的研究。
