School of Optometry and Vision Science, Faculty of Science, The University of New South Wales, Sydney, New South Wales, Australia; Dougenzaka Itoi Eye Clinic, Itoi building 1-10-19 Dougenzaka Shibuya-ku, Tokyo, Japan.
School of Optometry and Vision Science, Faculty of Science, The University of New South Wales, Sydney, New South Wales, Australia.
Cont Lens Anterior Eye. 2024 Dec;47(6):102311. doi: 10.1016/j.clae.2024.102311. Epub 2024 Sep 20.
This study aimed to investigate the effects of the combination of levofloxacin (LVFX) and cefmenoxime (CMX) on ocular isolates of Pseudomonas aeruginosa.
Twenty-three strains of P. aeruginosa isolated from microbial keratitis cases in Australia were utilized in this study. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each antibiotic alone were determined and the combined susceptibility of antibiotics was assessed through fractional inhibitory concentration index (FICI). Additionally, tolerance of a ciprofloxacin tolerant P. aeruginosa isolate to each antibiotic alone and combination were analyzed.
The median MIC and MBC values of CMX against P. aeruginosa were 16 µg/mL and 32 µg/mL, respectively. The median MIC and MBC values of LVFX were 0.5 µg/mL and 1 µg/mL, respectively, and all isolates were susceptible. In dual combination, the median of FICI of all strains was 0.63; seven strains showed synergistic effects (FICI≤0.5), and fifteen strains showed additive activities, while no strains exhibited antagonism. The isolate of P. aeruginosa that had previously exhibited tolerance to ciprofloxacin showed high tolerance to CMX alone and low tolerance to LVFX alone. This strain showed low tolerance to the combination of CMX and LVFX.
The combination of LVFX with CMX may have beneficial interactions which increase antibacterial activity against P. aeruginosa isolates and may be a feasible option for addressing the issue of bacteria resistant to each antibiotic.
本研究旨在探讨左氧氟沙星（LVFX）和头孢美唑（CMX）联合应用对铜绿假单胞菌眼部分离株的影响。
本研究使用了 23 株从澳大利亚微生物角膜炎病例中分离出的铜绿假单胞菌。单独测定了每种抗生素的最低抑菌浓度（MIC）和最低杀菌浓度（MBC），并通过部分抑菌浓度指数（FICI）评估了抗生素的联合敏感性。此外，还分析了对环丙沙星耐药的铜绿假单胞菌分离株对每种抗生素单独和联合用药的耐受性。
CMX 对铜绿假单胞菌的中位 MIC 和 MBC 值分别为 16μg/mL 和 32μg/mL。LVFX 的中位 MIC 和 MBC 值分别为 0.5μg/mL 和 1μg/mL，所有分离株均敏感。在双重组合中，所有菌株的 FICI 中位数为 0.63；7 株表现出协同作用（FICI≤0.5），15 株表现出相加作用，而没有菌株表现出拮抗作用。先前表现出对环丙沙星耐药的铜绿假单胞菌分离株对 CMX 单独使用表现出高耐药性，对 LVFX 单独使用表现出低耐药性。该菌株对 CMX 和 LVFX 的联合用药表现出低耐受性。
LVFX 与 CMX 的联合应用可能具有有益的相互作用，增加了对铜绿假单胞菌分离株的抗菌活性，可能是解决每种抗生素耐药细菌问题的可行选择。
