Sivas Cumhuriyet University, Faculty of Medicine, Department of Medical Microbiology, 58140, Sivas, Turkey.
Indian J Med Microbiol. 2022 Jul-Sep;40(3):399-403. doi: 10.1016/j.ijmmb.2022.04.004. Epub 2022 Apr 28.
In this study, it was aimed to investigate the combined synergistic efficacy of colistin (CT), meropenem (MEM), and ciprofloxacin (CIP) antibiotics on planktonic and biofilm forms in Myroidesodoratimimus strains isolated from various clinical specimens.
Antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method. In addition, minimum inhibitory concentrations (MIC) of CIP, MEM, and CT were studied using the standardized broth microdilution method. In vitro synergistic activity of antibiotics against M. odoratimimus planktonic bacteria strains was studied by the Micro Broth Checkerboard method. The microtiter plate (MtP) method was used to determine the effectiveness of antibiotics on M. odoratimimus biofilm formation.
A zone of inhibition was not observed against other antibiotics used except amikacin and linezolid in all strains. While CT/MEM and CT/CIP combinations have a synergistic effect on all strains, the combination CIP/MEM has an additive effect. According to the biofilm inhibition results, all three antibiotics inhibited biofilm formation. However, the efficacy of MEM (60.3-76.5%) and CIP (60.2-77.8%) was approximately two times higher than that of CT (25.4-34.5%). In addition, the effectiveness of combinations of antibiotics on biofilm formation was examined and the percentage of inhibition was 30.8% when CT was used alone, while the biofilm inhibition rates of CT/MEM and CT/CIP were 92.4% and 91.7%, respectively. MEM/CIP combination was inhibited biofilm formation by 75.7%.
This study is the first report showing the efficacy of CT, MEM and CIP antibiotics, which are frequently used in clinical practice, in combination on M. odoratimimus planktonic and biofilm forms. The findings of our study are particularly guiding for combined antibiotic treatment options in immunosuppressed patients admitted to an intensive care unit (ICU). The CT/MEM combination is currently used frequently. In addition, these results are important in terms of supporting in vitro that CT/CIP and MEM/CIP combinations can also be used as a treatment option in M. odoratimimus related infections.
本研究旨在探讨黏菌素（CT）、美罗培南（MEM）和环丙沙星（CIP）联合应用对从各种临床标本中分离的恶臭假单胞菌浮游和生物膜形式的协同增效作用。
采用 Kirby-Bauer 纸片扩散法测定抗生素敏感性。此外，采用标准化肉汤微量稀释法研究 CIP、MEM 和 CT 的最低抑菌浓度（MIC）。采用微量棋盘法研究抗生素对恶臭假单胞菌浮游菌的体外协同活性。采用微量滴定板（MtP）法测定抗生素对恶臭假单胞菌生物膜形成的影响。
除阿米卡星和利奈唑胺外，所有菌株对其他抗生素均未观察到抑菌环。虽然 CT/MEM 和 CT/CIP 联合对所有菌株均具有协同作用，但 CIP/MEM 联合具有相加作用。根据生物膜抑制结果，三种抗生素均能抑制生物膜形成。然而，MEM（60.3-76.5%）和 CIP（60.2-77.8%）的疗效约为 CT（25.4-34.5%）的两倍。此外，还检查了抗生素组合对生物膜形成的作用，单独使用 CT 时抑制率为 30.8%，而 CT/MEM 和 CT/CIP 的生物膜抑制率分别为 92.4%和 91.7%。MEM/CIP 联合抑制生物膜形成率为 75.7%。
本研究首次报道了临床常用的 CT、MEM 和 CIP 抗生素联合应用对恶臭假单胞菌浮游和生物膜形式的疗效。本研究的结果对于指导免疫抑制患者入住重症监护病房（ICU）时的联合抗生素治疗方案特别有指导意义。目前经常使用 CT/MEM 联合治疗。此外，这些结果在支持 CT/CIP 和 MEM/CIP 联合也可作为恶臭假单胞菌相关感染的治疗选择的体外研究中具有重要意义。
