The Streptococcus pyogenes capsule is required for adhesion of bacteria to virus-infected alveolar epithelial cells and lethal bacterial-viral superinfection
The Streptococcus pyogenes capsule is required for adhesion of bacteria to virus-infected alveolar epithelial cells and lethal bacterial-viral superinfection
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DOI：
10.1128/iai.72.10.6068-6075.2004
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发表时间：
2004-10-01
影响因子：
3.1
通讯作者：
Hamada, S
中科院分区：
文献类型：
--
作者：
Okamoto, S;Kawabata, S;Hamada, S
侵袭性A组链球菌（GAS）感染在全球范围内明显复苏，但原因尚不清楚。然而，我们最近在小鼠中证明，当非致死性鼻内GAS感染之前是非致死性甲型流感病毒（IAV）感染时，诱导致死性侵袭性GAS感染通常是结果。在本研究中，我们从GAS分离株中建立了几个同基因突变体，并评估了几个毒力因子作为诱导侵袭性GAS感染的候选因子。中断合成的胶囊，Mga，链球菌溶血素O，链球菌溶血素S，或链球菌致热外毒素B的GAS显着降低死亡率与IAV和突变体的重叠感染的小鼠。此外，GAS有机体粘附IAV感染的肺泡上皮细胞的数量显着减少与胶囊耗尽的突变体，虽然这不是与其他突变体的情况。野生型GAS被发现直接结合IAV颗粒，而未封装的突变体显示出更少的结合能力。这些结果表明，囊膜起着关键作用，在入侵宿主组织的GAS与IAV和GAS重叠感染。
An apparent worldwide resurgence of invasive group A Streptococcus (GAS) infections remains unexplained. However, we recently demonstrated in mice that when an otherwise nonlethal intranasal GAS infection is preceded by a nonlethal influenza A virus (IAV) infection, induction of lethal invasive GAS infections is often the result. In the present study, we established several isogenic mutants from a GAS isolate and evaluated several virulence factors as candidates responsible for the induction of invasive GAS infections. Disruption of the synthesis of the capsule, Mga, streptolysin O, streptolysin S, or streptococcal pyrogenic exotoxin B of GAS significantly reduced mortality among mice superinfected with IAV and a mutant. In addition, the number of GAS organisms adhering to IAV-infected alveolar epithelial cells was markedly reduced with the capsule-depleted mutant, although this was not the case with the other mutants. Wild-type GAS was found to bind directly to IAV particles, whereas the nonencapsulated mutant showed much less ability to bind. These results suggest that the capsule plays a key role in the invasion of host tissues by GAS following superinfection with IAV and GAS.