铜绿假单胞菌临床分离株基因型分析

Genotyping of Pseudomonas aeruginosa clinical isolates

目的分析某院各科室长期持续感染的铜绿假单胞菌(PA)分离株的基因型,探讨PA的基因变异情况。方法从某院各科室住院患者送检的标本中分离PA,对感染持续时间大于30天的菌株采用随机扩增多态性DNA(RAPD)基因分型技术获得RAPD指纹图谱,并进行同源性聚类分析,通过相似性系数了解PA之间的亲缘关系;对比PA的RAPD型别,判断是否存在爆发流行及同一患者连续感染的PA基因是否发生变异。结果共收集PA293株,其中感染持续时间大于30天的菌株117株,扩增出19种基因型条带,分别为A^S型,分型率100%;基因型相似系数范围为0.64~0.93,基因型A和G、基因型B和R、基因型D和E、基因型M和P的相似系数均为0.93,说明它们之间具有高度的同源性。重症医学科及烧伤整形外科各发生一起在不同患者之间检出相同RAPD型别PA菌株的情况,其余患者RAPD型别各不相同。4例患者连续感染的PA指纹图谱发生改变。结论某院各科室长期持续感染的PA分离株存在多种基因型,提示PA在感染过程中可发生基因变异,存在基因多态性。

Objective To analyze the genotypes of Pseudomonas aeruginosa（ PA） isolated from inpatients with longterm and continuous infection in various departments of hospital,the and to explore the genetic variation of PA. Methods The strains of PA were collected from specimens of various departments of inpatients,and then we amplified the strains in which the infection lasted for more than 30 days,obtained the RAPD fingerprinting by random amplified polymorphic DNA（ RAPD） genotyping technique,analyzed homology by homology clustering,and understood the genetic relationship between PA through the similarity coefficient. At the same time,we compared the RAPD type to determine whether there was an epidemic outbreak and whether there was a variation between the strains from the same patients with continuous infection. Results A total of 293 strains of PA were collected,including 117 strains in which the infection duration was longer than 30 days,and then 19 genotypes were amplified with A-S type,and the classification rate is 100%. The similarity coefficient ranged from 0. 64 to 0. 93,the similarity coefficient of genotypes A and G,genotypes B and R,genotypes D and E,genotypes M and P was 0. 93,indicating a high degree of homology between them. In the intensive care unit and burn plastic surgery,the same RAPD type was detected in different patients,the rest of the patients had different RAPD types.The PA fingerprints of 4 patients who suffered continuous infection changed. Conclusion There are many genotypes in PA isolates from patients in various departments of the hospital,which suggests that PA gene mutation occurs in the process of infection,and there is a genetic polymorphism.