抗菌肽人β防御素3对肺炎克雷伯菌临床菌株的抑制作用研究

Research on the inhibition on Klebsiella pneumoniae clinical isolates by antimicrobial peptide human β defensin 3

目的分析抗菌肽人β防御素3(hBD3)对肺炎克雷伯菌临床分离株的抑菌作用。方法合成抗菌肽hBD3,分别通过最低抑菌浓度(MIC)检测、直接杀菌试验、重要功能基因检测分析其对20株临床分离的肺炎克雷伯菌的直接抑制作用;并将其与阿莫西林、头孢他啶、环丙沙星联合应用,观察其对抗菌药物50%最低抑菌浓度(MIC50)和90%最低抑菌浓度(MIC90)的影响。结果hBD3对20株肺炎克雷伯菌的MIC为(22.3±6.6)μg/mL;在浓度达到8μg/mL时即有明显的杀菌作用。hBD3可上调ompC基因表达,下调yojL基因表达。在联用5μg/mL hBD3后,头孢他啶、环丙沙星的MIC50和MIC90值均明显降低,而阿莫西林的MIC50和MIC90值无明显变化。结论抗菌肽hBD3对肺炎克雷伯菌有明显的抑制作用,可望与抗菌药物联用治疗肺炎克雷伯菌感染。

Objective To analyze the inhibition effects of antimicrobial peptide human βdefensin 3 （hBD3 ） against Klebsiella pneumoniae clinical isolates.Methods Antimicrobial peptide hBD3 was synthesized.The direct inhibition on 20 Klebsiella pneumoniae clinical isolates were detected by minimal inhibitory concentration （MIC）test, antibacterial activity test and the analysis on some important functional genes.The antimicrobial peptide was combined with amoxicillin,ceftazidime and ciprofloxacin for observing the effects on antibiotic 50% MIC （MIC50）and 90% MIC （MIC90）.Results The MIC of hBD3 against Klebsiella pneumoniae clinical isolates was （22.3 ±6.6）μg/mL,the bactericidal activity was observed while hBD3 concentration was as high as 8 μg/mL.The hBD3 could improve the expression of ompC and reduce the expression of yojL.When 5 μg/mL hBD3 was added,the MIC50 and MIC90 against Klebsiella pneumoniae clinical isolates of ceftazidime and ciprofloxacin were dropped down.Conclusions There is a considerable antibacterial activity of antimicrobial peptide hBD3 against Klebsiella pneumoniae clinical isolates.It could be used to inhibit Klebsiella pneumoniae infection combined with antibiotics.