Kerr A R, Adrian P V, Estevão S, de Groot R, Alloing G, Claverys J-P, Mitchell T J, Hermans P W M
Division of Infection and Immunity, Joseph Black Building, University of Glasgow, University Avenue, Glasgow G12 8QQ, Scotland, United Kingdom.
Infect Immun. 2004 Jul;72(7):3902-6. doi: 10.1128/IAI.72.7.3902-3906.2004.
The Ami-AliA/AliB oligopeptide permease is an ATP-binding cassette transporter which is found in Streptococcus pneumoniae and which is involved in nutrient uptake. We investigated the role of the three paralogous oligopeptide-binding lipoproteins AmiA, AliA, and AliB by using murine models of pneumococcal colonization and invasive disease. A series of mutants lacking aliA, aliB, and amiA either alone or in combination as double or triple mutations were used. Inoculation of the nasopharynx with a mixture of the obl (oligopeptide-binding lipoprotein-negative) triple-mutant and wild-type (D39) bacteria resulted in significantly smaller numbers of obl bacteria colonizing the nasopharynx. The use of a mixture of individual mutants and wild-type pneumococci revealed that AmiA, AliA, and AliB were all required for successful colonization of the nasopharynx. The obl mutant was more attenuated than the aliB mutant but not the aliA or amiA mutant. Therefore, there is some redundancy in the Ami-AliA/AliB complex in terms of nasopharyngeal colonization, with AliA and AmiA being able to compensate for the removal of AliB. Animals with invasive disease caused by these mutants had survival times, bacterial loads, and inflammatory cytokine production levels similar to those of animals infected with wild-type pneumococci. Our results show that although the Ami-AliA/AliB complex is not required for virulence during pneumococcal pneumonia, it does play a role in colonization of the nasopharynx.
Ami - AliA/AliB寡肽通透酶是一种ATP结合盒转运蛋白，存在于肺炎链球菌中，参与营养物质摄取。我们通过使用肺炎球菌定植和侵袭性疾病的小鼠模型，研究了三种同源寡肽结合脂蛋白AmiA、AliA和AliB的作用。使用了一系列单独缺失aliA、aliB和amiA或作为双突变或三突变组合缺失的突变体。用obl（寡肽结合脂蛋白阴性）三突变体和野生型（D39）细菌的混合物接种鼻咽部，导致在鼻咽部定植的obl细菌数量显著减少。使用单个突变体和野生型肺炎球菌的混合物表明，AmiA、AliA和AliB都是鼻咽部成功定植所必需的。obl突变体比aliB突变体更减毒，但比aliA或amiA突变体不减毒。因此，在鼻咽部定植方面，Ami - AliA/AliB复合物存在一些冗余，AliA和AmiA能够补偿AliB的缺失。由这些突变体引起侵袭性疾病的动物的存活时间、细菌载量和炎性细胞因子产生水平与感染野生型肺炎球菌的动物相似。我们的结果表明，虽然Ami - AliA/AliB复合物在肺炎球菌肺炎期间的毒力方面不是必需的，但它在鼻咽部定植中确实起作用。
