Ouhara Kazuhisa, Komatsuzawa Hitoshi, Kawai Toshihisa, Nishi Hiromi, Fujiwara Tamaki, Fujiue Yoshihiro, Kuwabara Masao, Sayama Koji, Hashimoto Koji, Sugai Motoyuki
Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
J Antimicrob Chemother. 2008 Jun;61(6):1266-9. doi: 10.1093/jac/dkn106. Epub 2008 Mar 26.
The susceptibility of clinical isolates of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), to host-derived cationic antimicrobial peptides was investigated.
We examined the susceptibility of 190 clinical strains of methicillin-susceptible S. aureus (MSSA) and 304 strains of MRSA to two different classes of cationic antimicrobial peptides: LL-37 and human beta-defensin-3 (hBD3). Out of the total 494 clinical strains, a random selection of 54 S. aureus strains was examined to establish the relationship between the net charge, or zeta potential, of each strain and its susceptibility to hBD3 or LL-37. To further confirm bacterial susceptibility to either hBD3 or LL-37, we concurrently measured: (i) percentage survival after in vitro bacterial exposure and (ii) MBCs for both MRSA and MSSA strains.
Of the 54 randomly selected S. aureus strains, those MRSA strains resistant to LL-37 showed significantly higher zeta potentials than those susceptible to LL-37 (P < 0.05). In contrast, there was no difference in bacterial zeta potentials for MRSA strains that showed either resistance or susceptibility to hBD3. In addition, resistance to LL-37, but not to hBD3, as determined by either percentage survival or MBC, was significantly elevated in highly methicillin-resistant strains of S. aureus when compared with MSSA strains (P < 0.01).
Clinical strains of MRSA, but not MSSA, that demonstrated an increased net charge also showed elevated resistance to LL-37, but not to hBD3.
研究包括耐甲氧西林金黄色葡萄球菌（MRSA）在内的金黄色葡萄球菌临床分离株对宿主来源的阳离子抗菌肽的敏感性。
我们检测了190株甲氧西林敏感金黄色葡萄球菌（MSSA）临床菌株和304株MRSA对两类不同阳离子抗菌肽的敏感性：LL-37和人β-防御素-3（hBD3）。在总共494株临床菌株中，随机选择54株金黄色葡萄球菌菌株，以确定各菌株的净电荷或ζ电位与其对hBD3或LL-37的敏感性之间的关系。为进一步确认细菌对hBD3或LL-37的敏感性，我们同时测量了：（i）体外细菌暴露后的存活率百分比；（ii）MRSA和MSSA菌株的最低杀菌浓度（MBC）。
在随机选择的54株金黄色葡萄球菌菌株中，对LL-37耐药的MRSA菌株的ζ电位显著高于对LL-37敏感的菌株（P<0.05）。相比之下，对hBD3耐药或敏感的MRSA菌株的细菌ζ电位没有差异。此外，与MSSA菌株相比，通过存活率百分比或MBC测定，耐甲氧西林程度高的金黄色葡萄球菌菌株对LL-37的耐药性显著升高，但对hBD3的耐药性没有显著升高（P<0.01）。
净电荷增加的MRSA临床菌株对LL-37的耐药性升高，但对hBD3的耐药性未升高，而MSSA菌株则不然。
