Upper and lower respiratory tract infection by Streptococcus pneumoniae is affected by pneumolysin deficiency and differences in capsule type
Upper and lower respiratory tract infection by Streptococcus pneumoniae is affected by pneumolysin deficiency and differences in capsule type
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DOI：
10.1128/iai.70.6.2886-2890.2002
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发表时间：
2002-06-01
影响因子：
3.1
通讯作者：
Andrew, PW
中科院分区：
文献类型：
--
作者：
Kadioglu, A;Taylor, S;Andrew, PW
肺炎球菌经常定植于上呼吸道，并且这些肺炎球菌被认为是下呼吸道感染和菌血症的储存库。我们研究了肺炎球菌毒素肺炎球菌溶血素如何影响肺炎球菌感染小鼠上呼吸道和下呼吸道的能力。使用野生型肺炎链球菌血清型2和3菌株、血清型2肺炎球菌溶血素缺陷突变体和重新插入肺炎球菌溶血素基因的血清型2突变体来研究定殖和疾病的差异。此外，我们还研究了肺炎球菌嵌合突变体（荚膜类型从血清2型转换为血清3型），以进一步了解荚膜在鼻咽感染中的作用。肺炎球菌溶血素的缺乏与鼻咽、气管和肺中肺炎球菌的数量显著降低有关。发现肺炎球菌荚膜类型的差异对鼻咽、气管和肺部的肺炎球菌感染有显著影响。然而，重要的是荚膜类型和遗传背景的组合，并且这种组合的影响随感染部位而变化。例如，在鼻咽中，野生型血清型3菌株和胶囊转换的突变体表现相似，而在肺中，转换为血清型3的突变体的存活率低于野生型血清型3菌株。荚膜类型和遗传背景的组合也决定了毒力。因此，野生型血清型3菌株是毒性的。而胶囊转换突变体是无毒的。
Pneumococci frequently colonize the upper respiratory tract, and these pneumococci are believed to act as a reservoir for infection of the lower respiratory tract an bacteremia. We investigated how the pneumococcal toxin pneumolysin affects the capacity of pneumococci to infect the upper and lower respiratory tract of the mouse. Wild-type Streptococcus pneumoniae serotype 2 and 3 strains, a serotype 2 pneumolysin-deficient mutant, and a serotype 2 mutant with the pneumolysin gene reinserted were used to study differences in colonization and disease. In addition, we also examined a pneumococcal chimeric mutant (capsule type switched from serotype 2 to serotype 3) to gain further insight into the role that capsule plays in nasopharyngeal infection. Absence of pneumolysin was found to be associated with significantly lower numbers of pneumococci in the nasopharynx, trachea, and lungs. Differences in pneumococcal capsule type were found to have significant effects on pneumococcal infection of the nasopharynx, trachea, and lungs. However, it was the combination of capsule type and genetic background that was important, and the influence of this combination varied with the site of infection. For example, in the nasopharynx the wild-type serotype 3 strain and the capsule-switched mutant behaved similarly, whereas in the lungs the mutant that was switched to serotype 3 survived less well than the wild-type serotype 3 strain. The combination of capsule type and genetic background also determined virulence. Thus, the wild-type serotype 3 strain was virulent. whereas the capsule-switched mutant was avirulent.