Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan; Center for Postgraduate Education and Training, National Center for Child Health and Development, Tokyo, Japan.
Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan.
J Infect Chemother. 2020 Jul;26(7):765-768. doi: 10.1016/j.jiac.2020.02.016. Epub 2020 Apr 22.
Bordetella pertussis (B. pertussis) infection occasionally causes severe respiratory infections in children. Potential association between virulence-associated gene alleles and severe clinical outcomes has been suggested; however, frequencies of these alleles in pediatric patients with severe pertussis have not been clarified. We retrospectively tested stored respiratory samples collected from B. pertussis-positive patients by polymerase chain reaction targeting for major virulence-associated genes; fimbrae (fim) serotype 3 (fim3), pertactin (prn), pertussis toxin A (ptxA), and pertussis toxin promotor (ptxP). Based on the identified sequences, multilocus sequence typing (MLST) was conducted. Association of gene allele frequency and clinical outcomes such as management in pediatric intensive care unit, intubation, and mortality was analyzed. Out of 25 patients with available samples, the most prevalent allele for each virulence-associated gene was fim3A (17/21, 83%), ptxA1 (20/23, 87%), prn2 (13/16, 81%), and ptxP3 (14/17, 82%). In the study, total of 3 MLST types were identified; MLST-1 from 3 patients (19%), MLST-2 from 10 patients (63%), and MLST-4 from 3 patients (19%). Detection rate of the major MLST type; MLST-2 was significantly higher for patients who required intubation compared to those who did not (6/6, 100% vs 4/10, 40%; p = 0.034). In conclusion, MLST-2 was the most common MLST type in B. pertussis isolated from Japanese children with severe pertussis. Further studies investigating its causal association with disease severity is warranted.
百日咳博德特氏菌（B. pertussis）感染偶尔会导致儿童严重呼吸道感染。已经有人提出了与毒力相关基因等位基因和严重临床结局之间的潜在关联；然而，儿科重症百日咳患者中这些等位基因的频率尚未阐明。我们通过聚合酶链反应（PCR）针对主要毒力相关基因（fimbrae [fim] 3 型（fim3）、pertactin [prn]、百日咳毒素 A（ptxA）和百日咳毒素启动子（ptxP））检测了从百日咳博德特氏菌阳性患者中收集的存储呼吸道样本。根据鉴定的序列，进行了多位点序列分型（MLST）。分析了基因等位基因频率与临床结局的关联，例如儿科重症监护病房的管理、插管和死亡率。在有可用样本的 25 名患者中，每个毒力相关基因最常见的等位基因是 fim3A（17/21，83%）、ptxA1（20/23，87%）、prn2（13/16，81%）和 ptxP3（14/17，82%）。在该研究中，共鉴定出 3 种 MLST 型；3 名患者（19%）为 MLST-1 型，10 名患者（63%）为 MLST-2 型，3 名患者（19%）为 MLST-4 型。主要 MLST 型的检出率；需要插管的患者 MLST-2 型明显高于无需插管的患者（6/6，100% vs 4/10，40%；p=0.034）。总之，MLST-2 是日本儿童重症百日咳分离株中最常见的 MLST 型。需要进一步研究其与疾病严重程度的因果关系。
