Generation of Campylobacter jejuni genetic diversity in vivo
Generation of Campylobacter jejuni genetic diversity in vivo
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DOI：
10.1046/j.1365-2958.2002.02930.x
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发表时间：
2002-04-01
影响因子：
3.6
通讯作者：
Duim, B
中科院分区：
文献类型：
--
作者：
de Boer, P;Wagenaar, JA;Duim, B
分子流行病学研究表明，水平遗传交换是病原菌生物多样性的主要原因。我们通过寻找空肠弯曲菌菌株之间遗传物质交换的直接体内证据，对细菌肠道病原体空肠弯曲菌的这一概念进行了测试。为此，两个抗生素抗性标记被插入到遗传上不同的、自然转化的空肠弯曲菌菌株的hio或htrA基因中。在实验感染鸡的过程中，分析了同源和异源菌株在体内外共培养后抗性标记的遗传交换。所有供试菌株的组合在体外和从鸡肠中都获得了双抗性重组体。用Southern blotting结合FLAA聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)、扩增片段长度多态性(AFLP)和脉冲场凝胶电泳法(PFGE)证实了同源和异源菌株之间的DNA双向遗传交换。对分离的重组子进行的广泛的PFGE分析表明，在实验感染过程中，除了抗生素耐药基因的同源重组外，还经常发生基因重排。总之，这些数据明确地表明，在空肠弯曲菌感染期间，在体内确实发生了菌株间的遗传交换以及基因组内的改变。这些事件可能解释了观察到的这种病原体的基因组可塑性。
Molecular epidemiology studies suggest that horizontal genetic exchange is a major cause of pathogen biodiversity. We tested this concept for the bacterial enteropathogen Campylobacter jejuni by seeking direct in vivo evidence for the exchange of genetic material among Campylobacter strains. For this purpose, two antibiotic resistance markers were inserted into the hipO or htrA gene of genetically distinct and naturally transformable C. jejuni strains. Genetic exchange of the resistance markers was analysed after co-cultivation of homologous and heterologous strains in vitro and in vivo during experimental infection of chickens. Double-resistant recombinants were obtained both in vitro and from the chicken intestine for all combinations of strains tested. Bidirectional genetic exchange of DNA between homologous and heterologous strains was confirmed by Southern blotting in combination with flaA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), amplified fragment length polymorphism (AFLP) and pulsed field gel electrophoresis (PFGE). Extensive PFGE analyses of isolated recombinants indicated the frequent occurrence of genetic rearrangements during the experimental infection, in addition to the homologous recombination of the antibiotic resistance genes. Together, the data indicate unequivocally that interstrain genetic exchange as well as intragenomic alterations do occur in vivo during C. jejuni infection. These events probably explain the genome plasticity observed for this pathogen.