Genotypic and phenotypic variation in Pseudomonas aeruginosa reveals signatures of secondary infection and mutator activity in certain cystic fibrosis patients with chronic lung infections.
Genotypic and phenotypic variation in Pseudomonas aeruginosa reveals signatures of secondary infection and mutator activity in certain cystic fibrosis patients with chronic lung infections.
复制标题
铜绿假单胞菌的基因型和表型变异揭示了某些患有慢性肺部感染的囊性纤维化患者的继发感染和突变活性特征。
DOI：
10.1128/iai.05282-11
复制
发表时间：
2011
影响因子：
3.1
通讯作者：
Rosenzweig,Frank
中科院分区：
文献类型：
--
作者：
Warren,AshleyE;Boulianne-Larsen,CarlaM;Chandler,ChristineB;Chiotti,Kami;Kroll,Evgueny;Miller,ScottR;Taddei,Francois;Sermet-Gaudelus,Isabelle;Ferroni,Agnes;McInnerney,Kathleen;Franklin,MichaelJ;Rosenzweig,Frank
铜绿假单胞菌对囊性纤维化肺的进化适应受到遗传变异的限制，而遗传变异取决于水平基因转移和突变供应的速度。由于在继发感染或突变子出现后，它们可能会增加，所以我们试图确定有或没有突变子的人群中继发感染的发生率和遗传变异性。用重复序列聚合酶链式反应(rep-PCR)、脉冲场凝胶电泳法(PFGE)和多位点序列分型法(MLST)对3年来收集的16例患者的49株细菌进行了耐药表型和突变基因分型。尽管表型和遗传多态广泛存在，并且在纵向序列内的聚集性比纵向序列之间更强，但它们的分布揭示了继发感染的情况。然而，序列数据表明，谱系间重组早于最初的菌株分离。突变子系列比非突变子更有可能对抗生素产生多重耐药性，但其核苷酸序列并不一定更具变异性。一个突变子和一个非突变子序列在错配修复基因座上进行测序，并使用DNA微阵列分析基因含量。两者都是野生型，但突变者携带8-bpmuT S缺失，导致移码突变。这两个系列都缺乏编码菌毛蛋白、铁载体和毒力因子的126个基因，这些基因的失活与慢性感染期间的适应有关。突变者表现出几倍以上的基因丢失，这些基因具有与移动元素、运动和依恋相关的功能。在一个非突变子中观察到105kb，86-基因缺失，导致与吡喃佛定合成相关的毒力因子和多药外排调节子的元件丢失。DNA修复活动减弱可能会促进快速进化变化，但不是绝对必要的。
Evolutionary adaptation of Pseudomonas aeruginosa to the cystic fibrosis lung is limited by genetic variation, which depends on rates of horizontal gene transfer and mutation supply. Because each may increase following secondary infection or mutator emergence, we sought to ascertain the incidence of secondary infection and genetic variability in populations containing or lacking mutators. Forty-nine strains collected over 3 years from 16 patients were phenotyped for antibiotic resistance and mutator status and were genotyped by repetitive-sequence PCR (rep-PCR), pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). Though phenotypic and genetic polymorphisms were widespread and clustered more strongly within than between longitudinal series, their distribution revealed instances of secondary infection. Sequence data, however, indicated that interlineage recombination predated initial strain isolation. Mutator series were more likely to be multiply antibiotic resistant, but not necessarily more variable in their nucleotide sequences, than nonmutators. One mutator and one nonmutator series were sequenced at mismatch repair loci and analyzed for gene content using DNA microarrays. Both were wild type with respect tomutL, but mutators carried an 8-bpmutSdeletion causing a frameshift mutation. Both series lacked 126 genes encoding pilins, siderophores, and virulence factors whose inactivation has been linked to adaptation during chronic infection. Mutators exhibited loss of severalfold more genes having functions related to mobile elements, motility, and attachment. A 105-kb, 86-gene deletion was observed in one nonmutator that resulted in loss of virulence factors related to pyoverdine synthesis and elements of the multidrug efflux regulon. Diminished DNA repair activity may facilitate but not be absolutely required for rapid evolutionary change.