Rapid and Specific Detection, Molecular Epidemiology, and Experimental Virulence of the O16 Subgroup within Escherichia coli Sequence Type 131
Rapid and Specific Detection, Molecular Epidemiology, and Experimental Virulence of the O16 Subgroup within Escherichia coli Sequence Type 131
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DOI：
10.1128/jcm.03502-13
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发表时间：
2014-05-01
影响因子：
9.4
通讯作者：
Denamur, Erick
中科院分区：
文献类型：
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作者：
Johnson, James R.;Clermont, Olivier;Denamur, Erick
大肠杆菌序列 131 型 (ST131) 是一种广泛传播的多重耐药肠外病原体，通常表现出 O25b:H4 血清型。然而，某些 ST131 分离株表现出血清型 O16:H5，并且源自与经典 O25b:H4 ST131 进化枝不同的系统发育进化枝。通过 Achtman 多位点序列分型 (MLST) 系统和针对 mdh 和 gyrB 基因中 ST131 特异性序列多态性的筛选 PCR 测定，将这两个进化枝分配给 ST131。然而，巴斯德研究所 MLST 系统将它们分类为单独的 ST，并且针对 O25b rfb 区域的 ST131 PCR 方法和 pabB 中的 ST131 特异性多态性仅检测 O25b 相关进化枝。在这里，我们描述了一种基于 PCR 的新型方法，可以快速、特异性地检测 O16 相关的 ST131 进化枝。进化枝成员一致包含 fimH（1 型菌毛粘附素）等位基因 41 以及小范围的 gyrA 和 parC（氟喹诺酮靶基因）等位基因。进化枝成员的毒力基因型与经典 O25b: H4 ST131 分离株的毒力基因型相似；代表性分离株在小鼠皮下脓毒症模型中具有不同程度的致死性。几种脉冲类型跨越多个来源（成人、儿童、宠物和人类粪便样本）和地点。对最近临床大肠杆菌收集的分析表明，O16 ST131 进化枝在全球分布，占大肠杆菌总体分离株的 1% 至 5%，并且与其他 ST131 分离株相比，它与氨苄西林、庆大霉素和甲氧苄啶-磺胺甲恶唑的耐药性相关，并且与氟喹诺酮类和广谱头孢菌素敏感。我们基于新型 PCR 的检测方法促进了这一 O16 相关 ST131 进化枝的关注，这在未来 ST131 的流行病学研究以及临床应用中是有必要的。
Escherichia coli sequence type 131 (ST131), a widely disseminated multidrug-resistant extraintestinal pathogen, typically exhibits serotype O25b:H4. However, certain ST131 isolates exhibit serotype O16:H5 and derive from a phylogenetic clade that is distinct from the classic O25b: H4 ST131 clade. Both clades are assigned to ST131 by the Achtman multilocus sequence typing (MLST) system and a screening PCR assay that targets ST131-specific sequence polymorphisms in the mdh and gyrB genes. However, they are classified as separate STs by the Pasteur Institute MLST system, and an ST131 PCR method that targets the O25b rfb region and an ST131-specific polymorphism in pabB detects only the O25b-associated clade. Here, we describe a novel PCR-based method that allows for rapid and specific detection of the O16-associated ST131 clade. The clade members uniformly contained allele 41 of fimH (type 1 fimbrial adhesin) and a narrow range of alleles of gyrA and parC (fluoroquinolone target genes). The virulence genotypes of the clade members resembled those of classic O25b: H4 ST131 isolates; representative isolates were variably lethal in a mouse subcutaneous sepsis model. Several pulsotypes spanned multiple sources (adults, children, pets, and human fecal samples) and locales. An analysis of recent clinical E. coli collections showed that the O16 ST131 clade is globally distributed, accounts for 1 to 5% of E. coli isolates overall, and, when compared with other ST131 isolates, it is associated with resistance to ampicillin, gentamicin, and trimethoprim-sulfamethoxazole and with susceptibility to fluoroquinolones and extended- spectrum cephalosporins. Attention to this O16-associated ST131 clade, which is facilitated by our novel PCR-based assay, is warranted in future epidemiological studies of ST131 and, conceivably, in clinical applications.