Jin Hui, Xu Xiao-min, Mi Zu-huang, Mou Yi, Liu Pei
Department of Epidemiology and Health Statistics, Southeast University, Nanjing, Jiangsu 210009, China.
Chin Med J (Engl). 2009 Feb 5;122(3):301-6.
Acinetobacter baumannii has emerged as an important pathogen related to serious infections and nosocomial outbreaks around the world. However, of the frequently used methods, pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) in Acinetobacter baumannii genotyping lack the direct molecular proof of drug resistance. This study was conducted to establish a typing method based on drug resistant gene identification in contrast to traditional PFGE and AFLP in the period of nosocomial epidemic or outbreak.
From January 2005 to October 2005, twenty-seven strains of Acinetobacter species from Intensive Care Units, the Second Affiliated Hospital in Ningbo were isolated, including both epidemic and sporadic events. Susceptibility test, PFGE, AFLP and drug resistance gene typing (DRGT) were carried out to confirm the drug resistance and analyze the genotyping, respectively. PFGE was used as a reference to evaluate the typeability of DRGT and AFLP.
Twenty-seven strains of Acinetobacter displayed multiple antibiotic resistance and drug resistant genes, and beta-lactamase genes were detected in 85.2% strains. The result of DRGT was comparable to PFGE in Acinetobacter strains with different drug resistance though a little difference existed, and even suggested a molecular evolution course of different drug-resistant strains. AFLP showed great polymorphism between strains and had weak ability in distinguishing the drug resistance.
Compared to AFLP and PFGE, DRGT is useful to analyze localized molecular epidemiology of nosocomial infections and outbreaks, which would benefit clinical diagnosis and therapy.
鲍曼不动杆菌已成为一种与全球严重感染及医院感染暴发相关的重要病原菌。然而，在常用的方法中，鲍曼不动杆菌基因分型的脉冲场凝胶电泳（PFGE）和扩增片段长度多态性（AFLP）缺乏耐药性的直接分子证据。本研究旨在建立一种基于耐药基因鉴定的分型方法，以对比医院流行或暴发期间传统的PFGE和AFLP方法。
2005年1月至2005年10月，从宁波市第二附属医院重症监护病房分离出27株不动杆菌属菌株，包括流行株和散发病例。分别进行药敏试验、PFGE、AFLP和耐药基因分型（DRGT）以确认耐药性并分析基因分型。以PFGE作为参照来评估DRGT和AFLP的分型能力。
27株不动杆菌表现出多重耐药性及耐药基因，85.2%的菌株检测到β-内酰胺酶基因。在不同耐药性的不动杆菌菌株中，DRGT的结果与PFGE相当，尽管存在一些差异，甚至还提示了不同耐药菌株的分子进化过程。AFLP显示出菌株间的高度多态性，但区分耐药性的能力较弱。
与AFLP和PFGE相比，DRGT有助于分析医院感染和暴发的局部分子流行病学，这将有利于临床诊断和治疗。
