Charrier Cédric, Salisbury Anne-Marie, Savage Victoria J, Moyo Emmanuel, Forward Henry, Ooi Nicola, Cheung Jonathan, Metzger Richard, McGarry David, Walker Rolf, Cooper Ian R, Ratcliffe Andrew J, Stokes Neil R
Redx Pharma, Alderley Park, Cheshire SK10 4TG, UK
Redx Pharma, Alderley Park, Cheshire SK10 4TG, UK.
J Antimicrob Chemother. 2016 Oct;71(10):2831-9. doi: 10.1093/jac/dkw228. Epub 2016 Jun 26.
To evaluate the in vitro biological properties of a novel class of isothiazolone inhibitors of the bacterial type II topoisomerases.
Inhibition of DNA gyrase and topoisomerase IV activity was assessed using DNA supercoiling and decatenation assays. MIC and MBC were determined according to CLSI guidelines. Antibacterial combinations were assessed using a two-dimensional chequerboard MIC method. Spontaneous frequency of resistance was measured at various multiples of the MIC. Resistant mutants were generated by serial passage at subinhibitory concentrations of antibacterials and genetic mutations were determined through whole genome sequencing. Mammalian cytotoxicity was evaluated using the HepG2 cell line.
Representative isothiazolone compound REDX04957 and its enantiomers (REDX05967 and REDX05990) showed broad-spectrum bactericidal activity against the ESKAPE organisms, with the exception of Enterococcus spp., as well as against a variety of other human bacterial pathogens. Compounds retained activity against quinolone-resistant strains harbouring GyrA S83L and D87G mutations (MIC ≤4 mg/L). Compounds inhibited the supercoiling activity of wild-type DNA gyrase and the decatenation function of topoisomerase IV. Frequency of resistance of REDX04957 at 4× MIC was <9.1 × 10(-9). Against a panel of recent MDR isolates, REDX05967 demonstrated activity against Acinetobacter baumannii with MIC50 and MIC90 of 16 and 64 mg/L, respectively. Compounds showed a lack of cytotoxicity against HepG2 cells at 128 mg/L.
Isothiazolone compounds show potent activity against Gram-positive and -negative pathogens with a dual targeting mechanism-of-action and a low potential for resistance development, meriting their continued investigation as broad-spectrum antibacterial agents.
评估一类新型细菌II型拓扑异构酶异噻唑啉酮抑制剂的体外生物学特性。
使用DNA超螺旋和解连环分析评估DNA回旋酶和拓扑异构酶IV活性的抑制情况。根据CLSI指南测定最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。使用二维棋盘式MIC法评估抗菌联合用药情况。在MIC的不同倍数下测量自发耐药频率。通过在亚抑菌浓度的抗菌药物下连续传代产生耐药突变体，并通过全基因组测序确定基因突变情况。使用HepG2细胞系评估哺乳动物细胞毒性。
代表性异噻唑啉酮化合物REDX04957及其对映体（REDX05967和REDX05990）对除肠球菌属外的ESKAPE病原体以及多种其他人类细菌病原体显示出广谱杀菌活性。这些化合物对携带GyrA S83L和D87G突变的喹诺酮耐药菌株仍具有活性（MIC≤4mg/L）。化合物抑制野生型DNA回旋酶的超螺旋活性和拓扑异构酶IV的解连环功能。REDX04957在4×MIC时的耐药频率<9.1×10⁻⁹。针对一组近期的多重耐药分离株，REDX05967对鲍曼不动杆菌具有活性，MIC50和MIC90分别为16mg/L和64mg/L。化合物在128mg/L时对HepG2细胞无细胞毒性。
异噻唑啉酮化合物对革兰氏阳性和阴性病原体具有强大活性，具有双重作用机制且耐药发展潜力低，值得作为广谱抗菌剂继续研究。
