Genome Sequencing Verifies Relapsed Infection of Helicobacter cinaedi
Genome Sequencing Verifies Relapsed Infection of Helicobacter cinaedi
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DOI：
10.1093/ofid/ofz200
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发表时间：
2019-05-01
影响因子：
4.2
通讯作者：
Misawa, Naoaki
中科院分区：
文献类型：
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作者：
Sawada, Osamu;Gotoh, Yasuhiro;Misawa, Naoaki
背景。中国螺杆菌的反复感染经常被报道，长期的抗菌治疗是经验建议，以防止这种感染。然而，目前还没有研究表明复发感染是以前感染的复发还是不同克隆的再感染。一名69岁妇女在51天的间隔后出现复发的中国弧菌菌血症相关蜂窝织炎。我们从两次发作中每次获得的血培养中分离出10个菌落，并对其进行全基因组测序（WGS）。高置信度单核苷酸多态性（SNPs）通过基于装配的方法鉴定。异质SNP位点通过read mapping鉴定。并对代表性分离株对14种抗菌素的敏感性进行了检测。全基因组序列分析显示，20株分离株中只有6个SNP位点处于全基因组水平。基于6个snp，鉴定出5个宿主内变异（称为基因型）。首次感染均检出5种基因型；第二次感染仅检出2种基因型。尽管cinaedi克隆对氟喹诺酮类药物和大环内酯类药物具有较高的最低抑制浓度，并鉴定出相关突变，但6个snp中没有一个与额外耐药有关。这里分析的第二次感染是第一次感染的复发。在第一次感染中，已经存在一定程度的中国弧菌克隆宿主内基因组异质性。我们的研究结果提示较长的疗程对于根除棘球蚴病预防其感染复发的重要性。
Background. Recurrent infections of Helicobacter cinaedi are often reported, and long-term antimicrobial treatment is empirically recommended to prevent such infections. However, there have been no studies examining whether recurrent infections are relapses of former infections or reinfections with different clones.Methods. A 69-year-old woman presented with recurrent H cinaedi bacteremia-associated cellulitis after a 51-day interval. We isolated 10 colonies from the blood cultures obtained during each of the 2 episodes and subjected them to whole-genome sequencing (WGS). High-confidence single-nucleotide polymorphisms (SNPs) were identified by an assembly based method. Heterogeneous SNP sites were identified by read mapping. The susceptibility of a representative isolate to 14 antimicrobials was also examined.Results. Whole-genome sequence analysis revealed only 6 SNP sites among the 20 isolates at the whole-genome level. Based on the 6 SNPs, 5 within-host variants (referred to as genotypes) were identified. All 5 genotypes were detected in the first infection; however, only 2 genotypes were detected in the second infection. Although the H cinaedi clone showed a higher minimum inhibitory concentration to fluoroquinolones and macrolides and responsible mutations were identified, none of the 6 SNPs appeared related to additional resistance.Conclusions. The second infection analyzed here was a relapse of the first infection. A certain level of within-host genomic heterogeneity of the H cinaedi clone was already present in the first infection. Our results suggest the importance of longer treatment courses to eradicate H cinaedi for preventing the relapse of its infection.