Old Dominion University, Department of Chemistry and Biochemistry, USA.
Old Dominion University, Frank Reidy Research Center for Bioelectrics, USA.
Bioelectrochemistry. 2021 Aug;140:107797. doi: 10.1016/j.bioelechem.2021.107797. Epub 2021 Mar 9.
The Gram-positive anaerobic bacterium Cutibacterium acnes (C. acnes) is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. C. acnes can form biofilms; cells in biofilms are more resilient to antimicrobial stresses. Acne therapeutic options such as topical or systemic antimicrobial treatments often show incomplete responses. In this study we measured the efficacy of nanosecond pulsed electric fields (nsPEF), a new promising cell and tissue ablation technology, to inactivate C. acnes. Our results show that all tested nsPEF doses (250 to 2000 pulses, 280 ns pulses, 28 kV/cm, 5 Hz; 0.5 to 4 kJ/ml) failed to inactivate planktonic C. acnes and that pretreatment with lysozyme, a naturally occurring cell-wall-weakening enzyme, increased C. acnes vulnerability to nsPEF. Surprisingly, growth in a biofilm appears to sensitize C. acnes to nsPEF-induced stress, as C. acnes biofilm-derived cells showed increased cell death after nsPEF treatments that did not affect planktonic cells. Biofilm inactivation by nsPEF was confirmed by treating intact biofilms grown on glass coverslips with an indium oxide conductive layer. Altogether our results show that, contrary to other antimicrobial agents, nsPEF kill more efficiently bacteria in biofilms than planktonic cells.
革兰氏阳性厌氧细菌痤疮丙酸杆菌（C. acnes）是人类皮肤的共生菌，但也是一种机会性病原体，它有助于寻常痤疮的发病机制。C. acnes 可以形成生物膜；生物膜中的细胞对抗菌应激更有弹性。痤疮的治疗选择，如局部或全身抗菌治疗，往往显示不完全的反应。在这项研究中，我们测量了纳秒级脉冲电场（nsPEF）的功效，这是一种新的有前途的细胞和组织消融技术，以灭活 C. acnes。我们的结果表明，所有测试的 nsPEF 剂量（250 至 2000 个脉冲，280ns 脉冲，28kV/cm，5Hz；0.5 至 4kJ/ml）都不能灭活浮游 C. acnes，而溶菌酶预处理，一种天然存在的细胞壁弱化酶，增加了 C. acnes 对 nsPEF 的脆弱性。令人惊讶的是，生物膜中的生长似乎使 C. acnes 对 nsPEF 诱导的应激敏感，因为 nsPEF 处理后，生物膜衍生细胞的细胞死亡增加，而浮游细胞不受影响。通过用氧化铟导电层处理在玻璃载玻片上生长的完整生物膜来确认生物膜的 nsPEF 失活。总的来说，我们的结果表明，与其他抗菌剂相反，nsPEF 比浮游细胞更有效地杀死生物膜中的细菌。
