耐多黏菌素肺炎克雷伯菌的药敏特征及流行病学特点

Antibiotic resistance and epidemiological characteristics of polymyxin-resistant Klebsiella pneumoniae

目的:临床上已出现耐多黏菌素的肺炎克雷伯菌(Klebsiella pneumoniae,KPN),本研究分析耐多黏菌素KPN的药敏特征、流行病学特点,以及耐多黏菌素KPN产生的危险因素,以期为耐多黏菌素KPN感染的防治提供依据。方法:收集中南大学湘雅三医院(以下简称“本院”)的30株耐多黏菌素KPN临床菌株,分析其药敏特点。采用胶体金免疫层析法检测样本中是否存在KPC、OXA-48、VIM、IMP和NDM型碳青霉烯酶;拉丝试验初筛高毒力KPN;结晶紫染色法检测生物膜形成能力;棋盘法进行联合药敏试验(多黏菌素B和美罗培南、替加环素、头孢哌酮/舒巴坦);PCR检测多黏菌素相关耐药基因;多位点序列分型(multi-locus sequence typing,MLST)进行基因分型和构建进化树。收集耐碳青霉烯类(carbapenem-resistant,CR)-KPN多黏菌素耐药菌株(23株,实验组)、CR-KPN多黏菌素敏感菌株(57株,对照组),对耐多黏菌素KPN产生的可能危险因素行单因素分析,再进一步行多因素Logistic回归分析。检测多黏菌素B和多黏菌素E的连续诱导耐药情况。结果:30株耐多黏菌素KPN中,28株为CR-KPN,CRKPN均产KPC酶,4株拉丝实验阳性,多数菌株生物膜形成能力强。联合用药可有相加或协同效果。所有菌株均检出pmrA、phoP基因,未检测到mcr-1和mcr-2基因。MLST结果显示以ST11型为主。进化树表明耐多黏菌素的KPN未在本院形成医院暴发流行。使用过2种及以上不同类别的抗生素和使用过多黏菌素是多黏菌素耐药菌株产生的独立危险因素。连续使用多黏菌素可诱导耐药。结论:耐多黏菌素KPN对常用的抗菌药物几乎全部耐药,对其可采用以多黏菌素为基础的联合用药。在本院尚未分离出质粒介导的耐多黏菌素KPN。多黏菌素可诱导KPN形成耐药菌株,提示临床应合理使用抗菌药物,以延缓耐药性产生。

Objective:The emergence of polymyxin-resistant Klebsiella pneumoniae(KPN)in clinical settings necessitates an analysis of its antibiotic resistance characteristics,epidemiological features,and risk factors for its development.This study aims to provide insights for the prevention and control of polymyxin-resistant KPN infections.Methods:Thirty clinical isolates of polymyxin-resistant KPN were collected from the Third Xiangya Hospital of Central South University.Their antibiotic resistance profiles were analyzed.The presence of carbapenemase KPC,OXA-48,VIM,IMP,and NDM was detected using colloidal gold immunochromatography.Hypervirulent KPN was initially screened using the string test.Biofilm formation capacity was assessed using crystal violet staining.Combination drug susceptibility tests(polymyxin B with meropenem,tigecycline,cefoperazone/sulbactam)were conducted using the checkerboard method.Polymyxin-related resistance genes were detected by PCR.Multi-locus sequence typing(MLST)was performed for genotyping and phylogenetic tree construction.The study also involved collecting data from carbapenem-resistant(CR)-KPN polymyxin-resistant strains(23 strains,experimental group)and CR-KPN polymyxin-sensitive strains(57 strains,control group)to analyze potential risk factors for polymyxin-resistant KPN infection through univariate analysis and multivariate Logistic regression.The induction of resistance by continuous exposure to polymyxin B and colistin E was also tested.Results:Among the 30 polymyxin-resistant KPN isolates,28 were CR-KPN,all producing KPC enzyme.Four isolates were positive in the string test.Most isolates showed strong biofilm formation capabilities.Combination therapy showed additive or synergistic effects.All isolates carried the pmrA and phoP genes,while no mcr-1 or mcr-2 genes were detected.MLST results indicated that ST11 was the predominant type.The phylogenetic tree suggested that polymyxin-resistant KPN had not caused a hospital outbreak in the institution.The use of two or more different classes of antibiotics and the use of polymyxin were identified as independent risk factors for the development of polymyxin-resistant strains.Continuous use of polymyxin induced drug resistance.Conclusion:Polymyxin-resistant KPN is resistant to nearly all commonly used antibiotics,making polymyxin-based combination therapy a viable option.No plasmid-mediated polymyxin-resistant KPN has been isolated in the hospital.Polymyxin can induce resistance in KPN,highlighting the need for rational antibiotic use in clinical settings to delay the emergence of resistance.