重组人β-防御素3对革兰阴性菌的抗菌活性及其与细菌耐药性的关系

Antimicrobial activity of rhBD-3on Gram-negative bacteria and the correlation related to bacterial resistance

目的研究重组人β-防御素3(rhBD-3)对临床呼吸道分离的革兰阴性菌(GNB)菌株的体外抗菌活性,分析rhBD-3对GNB的最低抑菌浓度(MIC)与GNB对常用抗菌药物的耐药性间的关系。方法从呼吸科重症监护病房(RICU)不同时期住院患者采集的下呼吸道痰液中培养、分离、鉴定获得GNB菌株,包括铜绿假单胞菌(20株)、鲍曼不动杆菌(15株)和肺炎克雷伯杆菌(14株)。采用琼脂糖弥散抗菌法测定rhBD-3对菌株的MIC。在参与检测的抗菌药物中,计算各株细菌共对几种抗菌药物耐药,并计算这些抗菌药物占所有受检抗菌药物的比例,称为各株细菌的耐药比例。采用Pearson线性相关性检验分析菌株的耐药比例与rhBD-3的MIC间的关系。结果 rhBD-3对所测试的GNB菌株均表现出一定的抗菌活性(MIC8～64μg/ml),且表现出抗菌活性随浓度增高而增强的趋势。rhBD-3对肺炎克雷伯杆菌、铜绿假单胞菌、鲍曼不动杆菌3种菌株的MIC与菌株对临床常用抗菌药物的耐药性间无明显的相关性(分别P=0.921、r=0.087,P=0.711、r=0.076,P=0.162、r=0.038)。结论 rhBD-3对呼吸道分离的3种GNB菌株均有抗菌活性,且这种抗菌活性与菌株对临床常用抗菌药物的耐药特性无明确相关性。

Objective To evaluate in vitro the antimicrobial activity of recombinant human beta defensin 3（rhBD-3）on Gram negative bacteria（GNB）isolated from respiratory tract of patients,and explore the correlation between the antimicrobial activity of rhBD-3and GNB resistance against routine antimicrobials.Methods The minimum inhibitory concentration（MIC）of rhBD-3to GNB strains isolated from respiratory tract of inpatients of Respiratory Intensive Care Unit（RICU）,including 20strains of Pseudomonas aeruginosa,15strains of Acinetobacter baumannii and 14strains of Klebsiella pneumoniae,was measured with radial diffusion test.The resistance of each strain of P.aeruginosa,A.baumannii and K.pneumonia against routinely used antimicrobials were detected.The resistance percentage（the proportion of the antimicrobials number resisted by each strain in the total number of tested antimicrobials）was then calculated.The Pearson linearity correlation test was used to analyze the correlation between the resistance percentage and MIC of rhBD-3 to the bacterial strain.Results All the isolated bacterial strains were susceptible to rhBD-3（MIC：8-64μg/ml）,the antimicrobial activity of rhBD-3was enhanced as the concentration of rhBD-3increased,with no correlation between the antimicrobial activity of rhBD-3and the antimicrobials resistance of the bacterial strains（P=0.921,r=0.087;P=0.711,r=0.076;P=0.162,r=0.038,respectively）.Conclusions rhBD-3exhibits antimicrobial activity to 3kinds of bacterial strains isolated from respiratory tract of patients,and no correlation is found between the antimicrobial activity of rhBD-3on the bacterial strains and the resistance of these strains against routine antimicrobials.