呼吸机相关性肺炎细菌耐药基因的分子流行病学研究

Study on molecular epidemiology of the genes of ventilator-associated pneumonia responsible for drug resistance

目的了解呼吸机相关性肺炎细菌耐药性及耐药基因分子流行病学特征,为临床诊疗提供参考。方法对呼吸机相关肺炎(VAP)病原菌构成进行分析,采用纸片扩散法检测主要致病菌耐药情况,采用脉冲场凝胶电泳(PFGE)进行主要病原菌的同源性和分子分型研究。结果 572例机械性通气患者中VAP患者247例(占43.18%);共分离致病菌359株,其中革兰阴性菌为231株(64.35%),革兰阳性菌52株(14.48%),真菌76株(21.17%);所有致病菌中,铜绿假单胞菌是主要致病菌,为102株(占28.41%)。铜绿假单胞菌对头孢唑啉和头孢克洛完全耐药,对利福平、氟氯西林的耐药率为98.04%。铜绿假单胞菌共有19个基因型(A^R),在各基因型中,A型有37株(36.28%),B型9株(8.82%),C型6株(5.89%),D型6株(5.89%),E型5株(4.90%)。结论 VAP主要致病菌存在优势克隆株流行,需要加强耐药性检测,预防暴发流行。

Objective To explore the characteristics of bacterial resistance in ventilator-associated pneumonia （VAP） and the molecular epidemiological characteristics of genes responsible for drug resistance in order to provide a reference for clinical diagnosis and treatment. Methods The pathogens responsible for VAP were analyzed, and their drug resistance was tested using the disk diffusion method. Pulsed field gel electrophoresis was used to analyze the similarity of pathogens and molecular typing was performed. Results Of 572 patients on a ventilator, 247 （43.18%） were found to have VAP. In total, 359 strains of pathogens were isolated. Of these, 231 were strains of Gram-negative bacteria （64. 35%）, 52 were strains of Gram-positive bacteria （14.48%）, and 76 were strains of fungi （21. 17%）. Of the pathogens, the most prevalent was Pseudomonas aeruginosa （102 strains, 28.41%）. Pseudomonas aeruginosa was completely resistant to ce- fazolin and eefaclor and its resistance to rifampicin and flucloxacillin was as high as 98.04%. Pseudomonas aeruginosa was found in 19 genotypes （A--R）. There were a7 genotype A strains （36. 28%）, 9 genotype B strains （8.82%）, 6 genotype C strains （5.89 ~ ）, 6 genotype D strains （5.89 ~）, and 5 genotype E strains （4.90 ~）. Conclusion Domi- nant strains of the pathogens responsible for VAP are prevalent, and detection of their drug resistance must be enhanced to prevent an outbreak.