Proteomic Analysis of Resistance o Gram-Negative Bacteria to Chlorhexidine and Impacts on Susceptibility to Colistin, Antimicrobial Peptides, and Ceragenins
Proteomic Analysis of Resistance o Gram-Negative Bacteria to Chlorhexidine and Impacts on Susceptibility to Colistin, Antimicrobial Peptides, and Ceragenins
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DOI：
10.3389/fmicb.2019.00210
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发表时间：
2019-02-18
影响因子：
5.2
通讯作者：
Savage, Paul B.
中科院分区：
文献类型：
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作者：
Hashemi, Marjan M.;Holden, Brett S.;Savage, Paul B.
在临床环境中使用洗必泰引起了人们的担忧，即细菌反复暴露于亚致死剂量的洗必泰可能会导致洗必泰耐药性以及与其他阳离子抗菌药物（包括粘菌素、内源性抗菌肽（AMP）及其模拟物角藻素）的交叉耐药性。我们之前已经证明，耐粘菌素的革兰氏阴性细菌仍然对 AMP 和角藻素敏感。在这里，我们通过将革兰氏阴性细菌的标准菌株连续暴露于洗必泰以产生耐药生物体群体，研究了洗必太、粘菌素、AMP 和角藻素之间交叉耐药的可能性。此外，我们对氯己定耐药菌株进行了蛋白质组学研究，并将其与野生型菌株进行比较，以找出细菌对氯己定产生耐药性的途径。革兰氏阴性菌连续暴露于氯己定会导致最低抑菌浓度 (MIC) 增加四到八倍。尽管未接触粘菌素，但洗必泰耐药微生物对粘菌素的敏感性降低（MIC 增加 8 至 32 倍）。相比之下，当使用代表性 AMP（LL-37 和 Magainin I）和角藻素（CSA-44 和 CSA-131）进行测试时，氯己定抗性生物体具有与原始菌株相同的 MIC。这些结果表明，高度粘菌素耐药的革兰氏阴性病原体的出现与氯己定的使用流行之间可能存在联系。然而，使用洗必泰可能不会影响先天免疫防御（例如 AMP）及其模拟物（例如角藻素）。在这里，我们还表明，氯己定耐药性与铜绿假单胞菌中参与外膜生物发生的 LPS 组装和毒力因子的蛋白上调有关。此外，对氯己定的耐药性导致与分子伴侣、外排泵、鞭毛和细胞代谢相关的蛋白质表达水平升高。本研究全面概述了铜绿假单胞菌接触洗必泰和粘菌素后蛋白质组的进化变化。考虑到医院中持续使用洗必泰可能会影响粘菌素耐药菌株的出现，这些结果具有重要的临床意义。
Use of chlorhexidine in clinical settings has led to concerns that repeated exposure of bacteria to sub-lethal doses of chlorhexidine might result in chlorhexidine resistance and cross resistance with other cationic antimicrobials including colistin, endogenous antimicrobial peptides (AMPs) and their mimics, ceragenins. We have previously shown that colistin-resistant Gram-negative bacteria remain susceptible to AMPs and ceragenins. Here, we investigated the potential for cross resistance between chlorhexidine, colistin, AMPs and ceragenins by serial exposure of standard strains of Gram-negative bacteria to chlorhexidine to generate resistant populations of organisms. Furthermore, we performed a proteomics study on the chlorhexidine-resistant strains and compared them to the wild-type strains to find the pathways by which bacteria develop resistance to chlorhexidine. Serial exposure of Gram-negative bacteria to chlorhexidine resulted in four- to eight-fold increases in minimum inhibitory concentrations (MICs). Chlorhexidine-resistant organisms showed decreased susceptibility to colistin (8- to 32-fold increases in MICs) despite not being exposed to colistin. In contrast, chlorhexidine-resistant organisms had the same MICs as the original strains when tested with representative AMPs (LL-37 and magainin I) and ceragenins (CSA-44 and CSA-131). These results imply that there may be a connection between the emergence of highly colistin-resistant Gram-negative pathogens and the prevalence of chlorhexidine usage. Yet, use of chlorhexidine may not impact innate immune defenses (e.g., AMPs) and their mimics (e.g., ceragenins). Here, we also show that chlorhexidine resistance is associated with upregulation of proteins involved in the assembly of LPS for outer membrane biogenesis and virulence factors in Pseudomonas aeruginosa. Additionally, resistance to chlorhexidine resulted in elevated expression levels of proteins associated with chaperones, efflux pumps, flagella and cell metabolism. This study provides a comprehensive overview of the evolutionary proteomic changes in P aeruginosa following exposure to chlorhexidine and colistin. These results have important clinical implications considering the continuous application of chlorhexidine in hospitals that could influence the emergence of colistin-resistant strains.