In vitro resistance to the CSαβ-type antimicrobial peptide ASABF-α is conferred by overexpression of sigma factor sigB in Staphylococcus aureus
In vitro resistance to the CSαβ-type antimicrobial peptide ASABF-α is conferred by overexpression of sigma factor sigB in Staphylococcus aureus
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DOI：
10.1093/jac/dki070
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发表时间：
2005-05-01
影响因子：
5.2
通讯作者：
Kato, Y
中科院分区：
文献类型：
--
作者：
Zhang, H;Morikawa, K;Kato, Y
目的：猪蛔虫抗菌因子（Ascaris suum antibacterial factor，ASABF）是从线虫中分离得到的一种CS α β型抗菌肽。ASABF-α是ASABF的成员，对革兰氏阳性病原体金黄色葡萄球菌特别有效。在这项研究中，我们研究了sigB表达在S. ASABF抗性中的作用。aureus.Methods:基于对ASABF抗性菌株Mu 50的初步表征，我们推测替代性σ因子sigB可能调节对抗菌肽的抗性。为了检验这一假设，在NKSB（N315的sigB敲除衍生物）和其sigB过表达衍生物之间比较ASABF敏感性。此外，还对N315 ex进行了类似的实验，N315 ex是N315的SCCmec（葡萄球菌染色体盒mec）缺失突变体，含有β-内酰胺耐药必需基因。结果：与亲本菌株相比，sigB过表达的NKSB对ASABF-α的耐药性增强。结论：sigB基因的过表达可诱导N315 ex细胞对抗菌肽ASABF-α产生耐药性。SCCmec对于这种抗性不是必需的。
Objectives: ASABF (Ascaris suum antibacterial factor) is a CS alpha beta-type antimicrobial peptide isolated from nematodes. ASABF-alpha, a member of ASABF, is particularly effective against the Gram-positive pathogen Staphylococcus aureus. In this study, we investigated the role of sigB expression on ASABF-resistance in S. aureus.Methods: Based on preliminary characterization of the ASABF-resistant strain, Mu50, we speculated that the alternative sigma factor sigB may regulate resistance against antimicrobial peptides. To test this hypothesis, the ASABF susceptibility was compared between NKSB (a sigB-knockout derivative of N315) and its sigB-overexpressing derivative. In addition, similar experiments were carried out for N315ex, a deletion mutant of N315 for SCCmec (Staphylococcus cassette chromosome mec) which contains essential genes for beta-lactam resistance.Results: The sigB-overexpressing NKSB acquired an increased resistance to ASABF-alpha compared with the parent strain. The sigB-induced ASABF-alpha resistance was also observed in N315ex.Conclusions: The overexpression of sigB confers resistance to the antimicrobial peptide, ASABF-alpha. SCCmec is not essential for this resistance.