Pharmacologie cellulaire et moléculaire and Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium.
Antimicrob Agents Chemother. 2012 Dec;56(12):6166-74. doi: 10.1128/AAC.01031-12. Epub 2012 Sep 17.
In a previous study (L. G. Garcia et al., Antimicrob. Agents Chemother. 56:3700-3711, 2012), we evaluated the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent small-colony variants, respectively) of the parental COL methicillin-resistant Staphylococcus aureus strain and the pharmacodynamic profile of the intracellular activity of a series of antibiotics in human THP-1 monocytes. We have now examined the phagocytosis and intracellular persistence of the same strains in THP-1 cells activated by phorbol 12-myristate 13-acetate (PMA) and measured the intracellular activity of gentamicin, moxifloxacin, and oritavancin in these cells. Postphagocytosis intracellular counts and intracellular survival were lower in PMA-activated cells, probably due to their higher killing capacities. Gentamicin and moxifloxacin showed a 5- to 7-fold higher potency (lower static concentrations) against the parental strain, its hemB mutant, and the genetically complemented strain in PMA-activated cells and against the menD strain in both activated and nonactivated cells. This effect was inhibited when cells were incubated with N-acetylcysteine (a scavenger of oxidant species). In parallel, we observed that the MICs of these drugs were markedly reduced if bacteria had been preexposed to H(2)O(2). In contrast, the intracellular potency of oritavancin was not different in activated and nonactivated cells and was not decreased by the addition of N-acetylcysteine, regardless of the phenotype of the strains. The oritavancin MIC was also unaffected by preincubation of the bacteria with H(2)O(2). Thus, activation of THP-1 cells by PMA may increase the intracellular potency of certain antibiotics (probably due to synergy with reactive oxygen species), but this effect cannot be generalized to all antibiotics.
在之前的一项研究（L. G. Garcia 等人，《抗菌药物与化学疗法》56：3700-3711，2012）中，我们评估了亲代 COL 耐甲氧西林金黄色葡萄球菌菌株的 menD 和 hemB 突变体（分别对应于甲萘醌和血红素依赖性小菌落变体）的细胞内命运，以及一系列抗生素在人 THP-1 单核细胞中的细胞内活性的药效学特征。我们现在检查了同一系列菌株在被佛波醇 12-肉豆蔻酸 13-乙酸酯（PMA）激活的 THP-1 细胞中的吞噬作用和细胞内持久性，并测量了这些细胞中庆大霉素、莫西沙星和奥他万古霉素的细胞内活性。吞噬后细胞内计数和细胞内存活在 PMA 激活的细胞中较低，这可能是由于它们的更高的杀伤能力。庆大霉素和莫西沙星对亲代菌株、其 hemB 突变体和遗传互补菌株在 PMA 激活的细胞中以及在两种激活和未激活的细胞中对 menD 菌株的活性表现出 5 至 7 倍的更高效力（更低的静态浓度）。当细胞用 N-乙酰半胱氨酸（氧化剂的清除剂）孵育时，这种作用受到抑制。同时，我们观察到如果细菌预先暴露于 H2O2，这些药物的 MIC 值显著降低。相比之下，奥他万古霉素的细胞内效力在激活和未激活的细胞中没有差异，并且无论菌株的表型如何，加入 N-乙酰半胱氨酸都不会降低。奥他万古霉素的 MIC 也不受细菌与 H2O2 预孵育的影响。因此，PMA 激活 THP-1 细胞可能会增加某些抗生素的细胞内效力（可能是由于与活性氧物质的协同作用），但这种效应不能推广到所有抗生素。
