鼻咽癌放疗患者铜绿假单胞菌感染基因型同源性

Homology analysis of nasopharyngeal carcinoma radiotherapy in patients with genotypes of Pseudomonas aeruginosa infection

目的探讨鼻咽癌放疗患者铜绿假单胞菌(PA)感染的病原菌临床分布、耐药特点及其基因型(同源)亲缘关系。方法采用BD phoenix 100全自动微生物鉴定药敏系统和CLSI M100-S23指南对临床分离菌进行鉴定和耐药表型分组,应用随机引物扩增多态性(RAPD)技术进行基因分型同源性分析。结果 49株PA来源于43位发生不同程度医院感染的鼻咽癌放疗患者,主要分布在咽拭子(46.94%)、痰(32.65%)、口腔分泌物(10.20%)等临床感染标本,耐药表型分组分别为Ⅰ组32株、Ⅱ组7株、Ⅲ组5株、Ⅳ组5株。49份PA样本经扩增后电泳出46个电泳图谱,分19个基因型别。在放疗二区高分布的H型菌株(57.14%)与在放疗四区高分布的J型菌株(60.00%)高度同源,耐药Ⅲ组、Ⅳ组的组内及组间型别亲缘关系不明显。不同病区鼻咽癌放疗患者之间存在基因型高度同源的PA感染局部流行,不同型别高耐药菌株的感染散发,部分亲缘关系密切菌株的耐药表型相似。结论应用基因分型技术检测分析病原菌同源性对医院感染监测和追踪具有重要意义。

Objective To investigate the clinical distributions, drug-fast features and gene homology of pathogenic bacteria in pseudomonas aeruginosa （PA） infection of nasopharyngeal carcinoma （NPC） patients undergoing radiotherapy. Methods The drug resistant phenotypes of clinical isolated bacteria were identified by using BD Phoenix 100 automatic bacteria identification system and conducted under CLSI M100-S23 guidelines. The gene homology was analyzed with random amplified polymorphic DNA（RAPD） technique. Results 49 strains of PA were observed from 43 NPC patients with nosocomial infection and the major infected sample types were consisted of throat swab （46.94%）, phlegm （32.65%）, and oral secretions （10.20%）. 32 strains of drug-fast phenotypes in group Ⅰ, 7 strains in group Ⅱ, 5 strains in group Ⅲ, 5 strains in group Ⅳ, and 5 strains in group Ⅴ were detected. 46 electrophoresis diagrams and 19 genotypes were identified from 49 PA samples. The highly homologous genotypes of type H strain and type J strain were observed in the Second Ward of Radiotherapy （57.14%） and the Fourth Ward of Radiotherapy （60.0%）, respectively. And there were no significant genetic relations in drug-fast group Ⅲ and group Ⅳ. The highly homologous of PA were localized epidemic in different wards, while the sporadic infections were observed in some highly resistant strains with different genotypes and the similarity drug-fast features were founded in the strains with close relationship. Conclusion It is important to analyze the gene homology of pathogenic bacteria in monitoring and tracking nosocomial infections by using the genotyping technologies.