香芹酚对耐碳青霉烯类肺炎克雷伯菌生物膜的体外抑制作用研究

目的：研究香芹酚对耐碳青霉烯类肺炎克雷伯菌（CRKP）生物膜的体外抑制作用，及其与美罗培南和左氧氟沙星的联用效果。方法：采用肉汤稀释法检测亚胺培南和美罗培南对10株临床分离肺炎克雷伯菌的最低抑菌浓度（MIC），微量肉汤稀释法测定香芹酚的MIC和最低杀菌浓度（MBC）；通过生长曲线法检测香芹酚对CRKP生长能力的影响；采用结晶紫染色法测定香芹酚对CRKP生物膜形成能力影响，微量肉汤稀释法测定最低抑制生物膜浓度（MBIC）和最低清除生物膜浓度（MBEC）；采用微量棋盘法测定联合抗生物被膜分数（FBICs）。结果：香芹酚对2株CRKP的MIC和MBC分别为156和313 μg·mL-1，香芹酚的MBIC和MBEC分别为313和1250 μg·mL-1，明显降低CRKP1的生长能力和生物膜形成能力，与美罗培南和左氧氟沙星的FBIC分别为0.31和0.37。结论：香芹酚可以抑制CRKP生长和生物膜的生成，与美罗培南和左氧氟沙星联合用药有协同抑制CRKP生物膜作用，为治疗CRKP感染提供新的思路。

Inhibitory Effects of Carvacrol on Biofilms of Carbapenem-resistant Klebsiella Pneumoniae in vitro

Objective: To investigate carvacrol on its anti-biofilm activity against carbapenem-resistant Klebsiella pneumoniae (CRKP) in vitro, and its combined effects with meropenem and levofloxacin. Methods: Minimum inhibition concentrations (MIC) of imipenem and meropenem against 10 clinically isolated Klebsiella pneumoniae were detected by a broth micro-dilution method. MIC and minimal bactericidal concentration (MBC) of carvacrol were determined by broth micro-dilution. The effects of carvacrol on the growth of CRKP were determined by growth curves. Its effect on CRKP biofilm formation was determined by crystal violet staining. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were determined by the broth micro-dilution method. The fractional biofilm inhibition concentrations (FBICs) were determined by a microdilution checkerboard method. Results: The MIC and MBC of carvacrol against two strains of CRKP in vitro were 156 μg·mL-1 and 313 μg·mL-1. The MBIC and MBEC of carvacrol against biofilm of CRKP1 were 313 μg·mL-1 and 1250 μg·mL-1, respectively. Carvacrol significantly reduced the growth and biofilm formation abilities of CRKP. FBICs of carvacrol in combination with meropenem and levofloxacin were 0.31 and 0.37, respectively. Conclusion: Carvacrol have antibacterial and antibiofilm activities against CRKP in vitro, and carvacrol combine with meropenem and levofloxacin have synergistic antibiofilm effects on CRKP, which provides a new idea for the treatment of CRKP infection.