Experimentally Evolved Staphylococcus aureus Survives in the Presence of Pseudomonas aeruginosa by Acquiring Mutations in the Amino Acid Transporter, GltT.
Experimentally Evolved Staphylococcus aureus Survives in the Presence of Pseudomonas aeruginosa by Acquiring Mutations in the Amino Acid Transporter, GltT.
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实验进化的金黄色葡萄球菌通过氨基酸转运蛋白 GltT 发生突变，在铜绿假单胞菌存在下存活。
DOI：
10.1101/2023.07.24.550428
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Goldberg,JoannaB
中科院分区：
文献类型：
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作者：
Alexander,AshleyM;Luu,JustinM;Raghuram,Vishnu;Bottacin,Giulia;vanVliet,Simon;Read,TimothyD;Goldberg,JoannaB
金黄色葡萄球菌和铜绿假单胞菌是从囊性纤维化（CF）相关的肺部感染中分离的最常见的细菌病原体。当在合并感染中发现这两种机会性病原体时，CF患者往往有更高的肺部加重率，并经历更快的肺功能下降。当在标准实验室条件下一起培养时，经常观察到铜绿假单胞菌有效地抑制S。金黄色葡萄球菌生长本研究组以前的工作表明，S。当与铜绿假单胞菌共培养时，来自CF感染的金黄色葡萄球菌具有分离株特异性存活能力。在这项研究中，我们设计了一个系列转移进化实验，以确定突变，使S。金黄色葡萄球菌以适应铜绿假单胞菌的存在。利用S. aureus USA300 JE2作为我们的祖先菌株，S.金黄色葡萄球菌与新鲜铜绿假单胞菌菌株PAO 1重复共培养。共培养8个周期后，S.观察到在PAO 1存在下存活更好的金黄色葡萄球菌群体。我们在高度保守的S.金黄色葡萄球菌天冬氨酸转运蛋白，gltT，这是独特的进化铜绿假单胞菌耐受菌株。随后的表型测试表明，gltT突变体具有降低的谷氨酸摄取，并胜过野生型S。当谷氨酸盐不存在于化学成分确定的培养基中时，这些发现共同证明了铜绿假单胞菌的存在对S.当两种细菌一起培养时，金黄色葡萄球菌改变其对关键氨基酸的摄取和代谢。
Staphylococcus aureus and Pseudomonas aeruginosa are the most common bacterial pathogens isolated from cystic fibrosis (CF) related lung infections. When both of these opportunistic pathogens are found in a coinfection, CF patients tend to have higher rates of pulmonary exacerbations and experience a more rapid decrease in lung function. When cultured together under standard laboratory conditions, it is often observed that P. aeruginosa effectively inhibits S. aureus growth. Previous work from our group revealed that S. aureus from CF infections have isolate-specific survival capabilities when cocultured with P. aeruginosa. In this study, we designed a serial transfer evolution experiment to identify mutations that allow S. aureus to adapt to the presence of P. aeruginosa. Using S. aureus USA300 JE2 as our ancestral strain, populations of S. aureus were repeatedly cocultured with fresh P. aeruginosa strain, PAO1. After 8 coculture periods, S. aureus populations that survived better in the presence of PAO1 were observed. We found two independent mutations in the highly conserved S. aureus aspartate transporter, gltT, that were unique to evolved P. aeruginosa-tolerant isolates. Subsequent phenotypic testing demonstrated that gltT mutants have reduced uptake of glutamate and outcompete wild-type S. aureus when glutamate is absent from chemically-defined media. These findings together demonstrate that the presence of P. aeruginosa exerts selective pressure on S. aureus to alter its uptake and metabolism of key amino acids when the two bacteria are cultured together.