Meurer Marita, de Buhr Nicole, Unger Linn Meret, Bonilla Marta C, Seele Jana, Nau Roland, Baums Christoph G, Gutsmann Thomas, Schwarz Stefan, von Köckritz-Blickwede Maren
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Foundation, Hanover, Germany.
Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hanover, Germany.
Front Microbiol. 2020 Jan 14;10:2911. doi: 10.3389/fmicb.2019.02911. eCollection 2019.
Host defense peptides or antimicrobial peptides (AMPs), e.g., cathelicidins, have recently been discussed as a potential new treatment option against bacterial infections. To test the efficacy of AMPs, standardized methods that closely mimic the physiological conditions at the site of infection are still needed. The aim of our study was to test the meningitis-causing bacteria and for their susceptibility to cathelicidins in culture medium versus cerebrospinal fluid (CSF). Susceptibility testing was performed in analogy to the broth microdilution method described by the Clinical and Laboratory Standard Institute (CLSI) to determine minimum inhibitory concentrations (MICs) of antimicrobial agents. MICs were determined using cation-adjusted Mueller-Hinton broth (CA-MHB), lysogeny broth (LB), Roswell Park Memorial Institute medium (RPMI) or Dulbecco's Modified Eagle's Medium (DMEM) (the latter two supplemented with 5% CA-MHB or blood) and compared with MICs obtained in porcine or human CSF. Our data showed that MICs obtained in CA-MHB as recommended by CLSI do not reflect the MICs obtained in the physiological body fluid CSF. However, the MICs of clinical isolates of tested in RPMI medium supplemented with CA-MHB, were similar to those of the same strains tested in CSF. In contrast, the MICs in the human CSF for the tested K1 strain were higher compared to the RPMI medium and showed even higher values than in CA-MHB. This highlights the need for susceptibility testing of AMPs in a medium that closely mimics the clinically relevant conditions.
宿主防御肽或抗菌肽（AMPs），例如cathelicidins，最近被讨论为对抗细菌感染的一种潜在新治疗选择。为了测试AMPs的疗效，仍然需要能够紧密模拟感染部位生理条件的标准化方法。我们研究的目的是测试引起脑膜炎的细菌对培养基和脑脊液（CSF）中cathelicidins的敏感性。按照临床和实验室标准协会（CLSI）描述的肉汤微量稀释法进行药敏试验，以确定抗菌剂的最低抑菌浓度（MICs）。使用阳离子调整的穆勒-欣顿肉汤（CA-MHB）、溶原肉汤（LB）、罗斯威尔公园纪念研究所培养基（RPMI）或杜尔贝科改良伊格尔培养基（DMEM）（后两种培养基补充5%的CA-MHB或血液）测定MICs，并与在猪或人CSF中获得的MICs进行比较。我们的数据表明，CLSI推荐的在CA-MHB中获得的MICs不能反映在生理体液CSF中获得的值。然而，在补充了CA-MHB的RPMI培养基中测试的临床分离株的MICs与在CSF中测试的相同菌株的MICs相似。相比之下，受试K1菌株在人CSF中的MICs高于RPMI培养基中的MICs，甚至比在CA-MHB中的值更高。这突出了在紧密模拟临床相关条件的培养基中对AMPs进行药敏试验的必要性。
