Genomic analysis and reconstruction of cefotaxime resistance in Streptococcus pneumoniae
Genomic analysis and reconstruction of cefotaxime resistance in Streptococcus pneumoniae
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DOI：
10.1093/jac/dkt113
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发表时间：
2013-08-01
影响因子：
5.2
通讯作者：
Ouellette, Marc
中科院分区：
文献类型：
--
作者：
Fani, Fereshteh;Brotherton, Marie-Christine;Ouellette, Marc
在全基因组范围内鉴定肺炎链球菌对第三代头孢菌素头孢噻肟耐药的非青霉素结合蛋白（PBP）突变。通过下一代测序确定肺炎头孢噻肟抗性分离株和用头孢噻肟抗性突变体的基因组DNA连续转化的两个转化体。通过在头孢噻肟敏感的背景下重建耐药性，证实了所鉴定的突变在头孢噻肟耐药性中的作用。基因组组装分析显示编码PBPs 2x、2a和3的基因中的突变，其中pbp 2x是所有突变体共有的唯一突变基因。改变的PBP等位基因转化为S. pneumoniae R6证实了PBP突变在头孢噻肟耐药中的作用，但这些不足以完全解释耐药水平。在四个测序的基因组中，至少有一个发现了31个额外的基因突变。非PBP抗性决定因素似乎主要是谱系特异性的。分别编码肽聚糖N-乙酰葡糖胺脱乙酰酶、糖基转移酶、ABC转运蛋白和分选酶的spr 1333、spr 0981、spr 1704和spr 1098中的突变，通过转化实验表明，这些菌株与抗性有关，并允许重建在亲本抗性菌株中观察到的全部抗性水平。结合功能研究的基因组分析已经允许在沙门氏菌中发现已知的和新的头孢噻肟抗性基因。肺炎。
To identify non-penicillin-binding protein (PBP) mutations contributing to resistance to the third-generation cephalosporin cefotaxime in Streptococcus pneumoniae at the genome-wide scale.The genomes of two in vitro S. pneumoniae cefotaxime-resistant isolates and of two transformants serially transformed with the genomic DNA of cefotaxime-resistant mutants were determined by next-generation sequencing. A role in cefotaxime resistance for the mutations identified was confirmed by reconstructing resistance in a cefotaxime-susceptible background.Analysis of the genome assemblies revealed mutations in genes coding for the PBPs 2x, 2a and 3, of which pbp2x was the only mutated gene common to all mutants. The transformation of altered PBP alleles into S. pneumoniae R6 confirmed the role of PBP mutations in cefotaxime resistance, but these were not sufficient to fully explain the levels of resistance. Thirty-one additional genes were found to be mutated in at least one of the four sequenced genomes. Non-PBP resistance determinants appeared to be mostly lineage specific. Mutations in spr1333, spr0981, spr1704 and spr1098, encoding a peptidoglycan N-acetylglucosamine deacetylase, a glycosyltransferase, an ABC transporter and a sortase, respectively, were implicated in resistance by transformation experiments and allowed the reconstruction of the full level of resistance observed in the parent resistant strains.This whole-genome analysis coupled to functional studies has allowed the discovery of both known and novel cefotaxime resistance genes in S. pneumoniae.