Given the increase in resistance to antibacterial agents, there is an urgent need for the development of new agents with novel modes of action. As an interim solution, it is also prudent to reinvestigate old or abandoned antibacterial compounds to assess their efficacy in the context of widespread resistance to conventional agents. In the 1970s, much work was performed on the development of peptide mimetics, exemplified by the phosphonopeptide, alafosfalin. We investigated the activity of alafosfalin, di-alanyl fosfalin and β-chloro-L-alanyl-β-chloro-L-alanine against 297 bacterial isolates, including carbapenemase-producing Enterobacterales (CPE) (n = 128), methicillin-resistant Staphylococcus aureus (MRSA) (n = 37) and glycopeptide-resistant enterococci (GRE) (n = 43). The interaction of alafosfalin with meropenem was also examined against 20 isolates of CPE. The MIC50 and MIC90 of alafosfalin for CPE were 1 mg/L and 4 mg/L, respectively and alafosfalin acted synergistically when combined with meropenem against 16 of 20 isolates of CPE. Di-alanyl fosfalin showed potent activity against glycopeptide-resistant isolates of Enterococcus faecalis (MIC90; 0.5 mg/L) and Enterococcus faecium (MIC90; 2 mg/L). Alafosfalin was only moderately active against MRSA (MIC90; 8 mg/L), whereas β-chloro-L-alanyl-β-chloro-L-alanine was slightly more active (MIC90; 4 mg/L). This study shows that phosphonopeptides, including alafosfalin, may have a therapeutic role to play in an era of increasing antibacterial resistance.
鉴于抗菌药物的抗药性增加,迫切需要开发具有新型作用方式的新药物。作为一种临时解决方案,重新评估旧的或被放弃的抗菌化合物,以评估它们在普遍抗药性背景下的有效性也是明智之举。上世纪70年代,对肽类模拟物的开发进行了大量工作,以磷酸肽类alafosfalin为例。我们对alafosfalin、二丙氨酰磷酸肽和β-氯代-L-丙氨酰-β-氯代-L-丙氨酸对297株细菌分离物的活性进行了研究,包括产碳青霉烯酶的肠杆菌科细菌(CPE)(n = 128)、耐甲氧西林金黄色葡萄球菌(MRSA)(n = 37)和耐糖肽类抗生素的肠球菌(GRE)(n = 43)。还对alafosfalin与美罗培南对20株CPE分离物的相互作用进行了检验。CPE的alafosfalin的MIC50和MIC90分别为1 mg/L和4 mg/L,与美罗培南结合时对20株CPE分离物中的16株表现出协同作用。二丙氨酰磷酸肽对耐糖肽类抗生素的肠球菌分离物表现出强效活性(MIC90;0.5 mg/L)和肠球菌(MIC90;2 mg/L)。Alafosfalin对MRSA仅有中等活性(MIC90;8 mg/L),而β-氯代-L-丙氨酰-β-氯代-L-丙氨酸稍微活性更高(MIC90;4 mg/L)。这项研究表明,包括alafosfalin在内的磷酸肽类可能在抗菌药物抗性增加的时代发挥治疗作用。