耐碳青霉烯类药的革兰阴性菌的临床研究

Clinical analysis of carbapenems-resistant Gram-negative bacteria

目的研究10株耐碳青霉烯类药的革兰阴性菌的耐药情况。方法采用微量肉汤稀释法或纸片扩散法检测碳青霉烯类等抗菌药物的敏感性;采用脉冲场凝胶电泳(PFGE)分析来自同一患者不同部位的鲍氏不动杆菌的同源性;采用聚合酶链反应(PCR)检测Ⅰ类整合酶、整合子和NDM-1基因,阳性产物进行DNA测序;分析感染患者血清降钙素原的变化。结果 6株革兰阴性菌对亚胺培南耐药,9株对美罗培南耐药,5株同时对亚胺培南和美罗培南耐药。从患者1的脑脊液、引流管和脓液标本分离的鲍氏不动杆菌,PFGE结果显示有1～2个条带的差异;PCR检测显示Ⅰ类整合酶均呈阳性,而整合子和NDM-1均呈阴性。从患者2血液和痰液标本中分离的鲍氏不动杆菌,PFGE结果完全一致,当该患者出现鲍氏不动杆菌的血液感染后,其血清降钙素原水平升至15.34ng/mL,患者随后很快死亡。结论耐碳青霉烯类药的鲍氏不动杆菌在呼吸道定植要引起高度重视,其随后的血液感染预后严重。

Objective To study the drug-resistance of 10 strains of carbapenems-resistant Gram-negative bacteria.Methods Broth microdilution or disk diffusion test were adopted to detect the sensitivity of carbapenems and other antibacterial drugs.Pulsed-field gel electrophoresis（PFGE） was used to analyze the homology of Acinetobacter baumannii collected from different parts of same patients.Polymerase chain reaction（PCR） was employed to detect class Ⅰ integrase,integron and NDM-1 gene,and their positive products were conducted DNA sequencing.Changes of serum procalcitonin of infected patients were analyzed.Results Six strains of Gram-negative bacteria were found to be resistant to imipenem,nine resistant to meropenem,five resistant to both imipenem and meropenem.When detecting Acinetobacter baumannii isolated from specimens of cerebrospinal fluid,drainage tube and pus of patient 1,differences were found in 1 to 2 bands by PFGE,and PCR detection revealed that class Ⅰ integrase from different spe-cimens were all positive,while integron and NDM-1 gene negative.When studying Acinetobacter baumannii isolated from specimens of blood and sputum of patient 2,PFGE results showed no difference.After Acinetobacter baumannii bloodstream infection occured in the patient 2,the serum level of procalcitonin rised to 15.34 ng/mL and the patient died soon.Conclusion Carbapenems-resistant Acinetobacter baumannii colonization in respiratory tract should arouse high attention due to the serious prognosis of patients with its further blood infection.