Vázquez Nicolás M, Fiorilli Graciela, Cáceres Guido Paulo A, Moreno Silvia
Leloir Institute and Institute of Biochemistry Research of Buenos Aires-IIBBA-CONICET, Patricias Argentinas 435 (C1405BWE), Ciudad Autónoma de Buenos Aires C1405, Argentina.
Service of Microbiology, Garrahan Pediatric Hospital, Combate de los Pozos 1881 (1245AAM), Ciudad Autónoma de Buenos Aires, Argentina.
Phytomedicine. 2016 Nov 15;23(12):1337-1343. doi: 10.1016/j.phymed.2016.07.010. Epub 2016 Jul 29.
Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to different commonly used antibiotics, stressing the need for further strategies to treat this human pathogen with worldwide prevalence. The use of phytochemicals within the current pharmacology is a promising approach to enhance the antimicrobial activity of common antibiotics in the battle against these bacteria.
The purpose of this study was to determine the antimicrobial effectiveness of carnosic acid, the major constituent of Rosmarinus officinalis L. leaves, in combination with gentamicin against multi-drug resistant MRSA clinical isolates obtained from pediatric patients with bacteremia.
Anti-MRSA activity was studied using the broth microdilution assay and time-kill method. Combinations of subinhibitory concentrations of carnosic acid and gentamicin were examined using the checkerboard method.
Carnosic acid exhibited a good antibacterial activity against all multidrug-resistant MRSA clinical isolates tested, which are resistant to four up to nine antibiotics. In addition, the combination of carnosic acid with gentamicin not only decreased the minimal inhibitory concentration (MIC) of both by 4- to 5-fold, but also improved the bactericidal potency of the common antibiotic by 32- to 40-fold against both gentamicin-susceptible and gentamicin-resistant MRSA clinical isolates. A clear bactericidal synergistic activity between carnosic acid and gentamicin in killing multidrug-resistant MRSA clinical isolates with a fractional bactericidal concentration index (FBCI) of 0.28-0.35 was demonstrated.
Our findings show the potential use of carnosic acid in combination with gentamicin as a promising alternative for the control of healthcare-associated infections caused by multidrug-resistant MRSA.
耐甲氧西林金黄色葡萄球菌（MRSA）对不同常用抗生素具有抗性，这凸显了需要进一步采取策略来治疗这种在全球广泛流行的人类病原体。在当前药理学中使用植物化学物质是一种有前景的方法，可增强常见抗生素在对抗这些细菌中的抗菌活性。
本研究的目的是确定迷迭香叶的主要成分鼠尾草酸与庆大霉素联合使用对从患有菌血症的儿科患者中分离出的多重耐药MRSA临床菌株的抗菌效果。
使用肉汤微量稀释法和时间杀菌法研究抗MRSA活性。使用棋盘法检查亚抑菌浓度的鼠尾草酸和庆大霉素的组合。
鼠尾草酸对所有测试的多重耐药MRSA临床菌株均表现出良好的抗菌活性，这些菌株对四种至九种抗生素具有抗性。此外，鼠尾草酸与庆大霉素的组合不仅使两者的最低抑菌浓度（MIC）降低了4至5倍，而且还使这种常用抗生素对庆大霉素敏感和庆大霉素耐药的MRSA临床菌株的杀菌效力提高了32至40倍。证明了鼠尾草酸和庆大霉素在杀死多重耐药MRSA临床菌株方面具有明显的杀菌协同活性，部分杀菌浓度指数（FBCI）为0.28 - 0.35。
我们的研究结果表明，鼠尾草酸与庆大霉素联合使用有可能作为控制由多重耐药MRSA引起的医疗保健相关感染的一种有前景的替代方法。
