The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, People's Republic of China.
Folia Microbiol (Praha). 2020 Aug;65(4):721-733. doi: 10.1007/s12223-020-00778-5. Epub 2020 Feb 21.
Enterococcus faecalis is a Gram-positive facultative anaerobe involved in many fatal or refractory infections of humans. Silver, often used as silver ions (Ag) or nanoparticles (AgNPs), is a strong and broad-spectrum antibacterial agent, but E. faecalis shows resistance against it. Despite this, the knowledge about the resistance of E. faecalis against silver is still lacking. In this study, the silver-resistant E. faecalis strains (AgR and ANR E. faecalis) were established through a serial selection method. Their biological and silver-resistant features as well as the Gene Ontology (GO) in comparison with the original E. faecalis were evaluated. The results showed that the silver-resistant E. faecalis could proliferate as original bacteria and had strong resistance against both Ag and AgNPs. The minimum bactericidal concentrations (MBCs) of AgNO on original, AgR, and ANR E. faecalis were 400 mg/L, 600 mg/L, and 500 mg/L, and the MBCs of AgNPs on these strains were 80 mg/L, 110 mg/L, and 130 mg/L, respectively. GO analysis revealed significant difference (P < 0.05) in gene expressions of biological process (BP), cellular component (CC), and molecular function (MF) among original, AgR, and ANR E. faecalis. These findings provided a significant basis for further understanding and managing the silver-resistance of E. faecalis in infection-control environments. The mechanism behind Ag/AgNPs resistance of E. faecalis needs to be further investigated.
粪肠球菌是一种革兰氏阳性兼性厌氧菌，与许多人类致命或难治性感染有关。银常被用作银离子（Ag）或纳米颗粒（AgNPs），是一种强广谱抗菌剂，但粪肠球菌对其表现出耐药性。尽管如此，关于粪肠球菌对银的耐药性的知识仍然缺乏。在这项研究中，通过连续选择法建立了耐银粪肠球菌株（AgR 和 ANR 粪肠球菌）。评估了它们的生物学特性和耐银特性以及与原始粪肠球菌的基因本体（GO）。结果表明，耐银粪肠球菌可以像原始细菌一样增殖，对 Ag 和 AgNPs 均具有很强的耐药性。AgNO 对原始、AgR 和 ANR 粪肠球菌的最小杀菌浓度（MBC）分别为 400mg/L、600mg/L 和 500mg/L，这些菌株对 AgNPs 的 MBC 分别为 80mg/L、110mg/L 和 130mg/L。GO 分析显示，原始、AgR 和 ANR 粪肠球菌的生物学过程（BP）、细胞成分（CC）和分子功能（MF）的基因表达存在显著差异（P<0.05）。这些发现为进一步了解和管理感染控制环境中粪肠球菌的耐银性提供了重要依据。需要进一步研究粪肠球菌对 Ag/AgNPs 耐药性的机制。
