Mechanism of respiratory infection due to H.influenae and protection gainst this infection

流感嗜血杆菌可引起各种呼吸道和全身感染，具体取决于细菌表型(包膜或非包膜)。携带结合细胞的流感嗜血杆菌的口咽上皮细胞有可能脱落并进入气管，在下呼吸道产生感染。因此，我们利用细胞结合组织建立了非分型流感嗜血杆菌感染的小鼠支气管肺炎模型和包膜(主要是b型)流感杆菌包裹的脓毒症/脑膜炎模型，在不产内酰胺酶和产生非分型流感嗜血杆菌的小鼠支气管肺炎中，阿莫西林在前者模型中获得了疗效，而在后者中则没有。这一结果表明，我们可能能够在新开发的模型中评估一种药物的体内活性。此外，我们以小鼠脓毒症/脑膜炎为模型，研究了菌毛在流感嗜血杆菌致病机制中的作用。流感嗜血杆菌菌毛的死亡率高于未菌毛的流感嗜血杆菌。对人血清的吞噬杀伤活性，菌毛状流感嗜血杆菌比非菌毛流感嗜血杆菌更敏感。菌毛生物结合的C3含量高于非菌毛生物。

Haemophilus influenzae can cause a variety of both respiratory and systemic infections depending on the bacterial phenotype (encapsulated or unencapsulated). There is a possibility that oropharyngeal epithelial cells carrying cell-bound H.influenzae may exfoliate and enter the trachea, and produce infection in thelower respiratory tract. Accordingly, we have developed murine bronchopneumonia model with nontypable H.influenzae and sepsis/meningitis model with encapsulated (mainly type b) H.influenzae, using cell-bound organisms.In murine bronchopneumonia with -lactamase nonproducing and producing nontypable H.influenzae the efficacy of amoxicillin was obtained in the former model and that was not obtained in the latter model. This result indicates that we may be able to evaluate the in vivo activity of a drug in a new developed model.Furthermore, we studied the role of fimbriae on the pathogenesis of type bH.influenzae, using murine sepsis/meningitis. The mortality rate in fimbriated H.influenzae was higher than that in nonfimbriated H.influenzae. To the phagocytosis-killing activity of human sera, fimbriated H.influenzae organisms were more susceptible than nonfimbriated H.influenzae organisms. Moreover, the content of C3 bound to fimbriated organisms was more than to nonfimbriated organisms.