Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia.
Infect Immun. 2012 Sep;80(9):3268-78. doi: 10.1128/IAI.00295-12. Epub 2012 Jul 9.
Streptococcus pneumoniae (the pneumococcus) continues to be responsible for a high level of global morbidity and mortality resulting from pneumonia, bacteremia, meningitis, and otitis media. Here we have used a novel technique involving niche-specific, genome-wide in vivo transcriptomic analyses to identify genes upregulated in distinct niches during pathogenesis after intranasal infection of mice with serotype 4 or 6A pneumococci. The analyses yielded 28 common, significantly upregulated genes in the lungs relative to those in the nasopharynx and 25 significantly upregulated genes in the blood relative to those in the lungs in both strains, some of which were previously unrecognized. The role of five upregulated genes from either the lungs or the blood in pneumococcal pathogenesis and virulence was then evaluated by targeted mutagenesis. One of the mutants (ΔmalX) was significantly attenuated for virulence in the lungs, two (ΔaliA and ΔilvH) were significantly attenuated for virulence in the blood relative to the wild type, and two others (ΔcbiO and ΔpiuA) were completely avirulent in a mouse intranasal challenge model. We also show that the products of aliA, malX, and piuA are promising candidates for incorporation into multicomponent protein-based pneumococcal vaccines currently under development. Importantly, we suggest that this new approach is a viable complement to existing strategies for the discovery of genes critical to the distinct stages of invasive pneumococcal disease and potentially has broad application for novel protein antigen discovery in other pathogens such as S. pyogenes, Haemophilus influenzae type b, and Neisseria meningitidis.
肺炎链球菌（肺炎球菌）仍然是导致全球肺炎、菌血症、脑膜炎和中耳炎发病率和死亡率居高不下的主要原因。在这里，我们使用了一种新的技术，涉及特定小生境的全基因组体内转录组分析，以鉴定在 4 型或 6A 型肺炎球菌经鼻腔感染小鼠后的发病过程中，不同小生境中上调的基因。分析结果显示，与鼻咽部相比，4 型和 6A 型肺炎球菌在肺部有 28 个显著上调的共同基因，与肺部相比，在血液中有 25 个显著上调的基因，其中一些是以前未被识别的。然后，通过靶向诱变评估了来自肺部或血液的 5 个上调基因在肺炎球菌发病机制和毒力中的作用。其中一个突变体（ΔmalX）在肺部的毒力显著减弱，两个（ΔaliA 和 ΔilvH）在血液中的毒力相对于野生型显著减弱，另外两个（ΔcbiO 和 ΔpiuA）在小鼠鼻腔挑战模型中完全无致病性。我们还表明，aliA、malX 和 piuA 的产物是纳入目前正在开发的多组分蛋白基肺炎球菌疫苗的有前途的候选物。重要的是，我们认为这种新方法是发现对侵袭性肺炎球菌病不同阶段至关重要的基因的现有策略的可行补充，并且可能具有广泛的应用前景，可用于发现其他病原体（如化脓性链球菌、乙型流感嗜血杆菌和脑膜炎奈瑟菌）的新型蛋白抗原。
