Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.
Microbiol Spectr. 2024 Sep 3;12(9):e0037524. doi: 10.1128/spectrum.00375-24. Epub 2024 Aug 8.
has emerged as a global health threat due to its role in the spread of antimicrobial resistance and because it is a frequent cause of hospital-acquired infections and neonatal sepsis. Capsular and lipopolysaccharide (LPS) O-antigen polysaccharide surface antigens are major immunogens that are useful for strain classification and are candidates for vaccine development. We have developed real-time PCR reagents for molecular serotyping, subtyping, and quantitation of the most prevalent LPS O-antigen types (i.e., O1, O2, O3, and O5) of . We describe two applications for this O-typing assay: for screening culture isolates and for direct typing of present in stool samples. We find 100% concordance between the results of the O-typing assay and whole-genome sequencing of 81 culture isolates, and >90% agreement in O-typing performed directly on specimens of human stool, with disagreement arising primarily from a lack of sensitivity of the culture-based comparator method. Additionally, we find evidence for mixed O-type populations at varying levels of abundance in direct tests of stool from a hospitalized patient population. Taken together, these results demonstrate that this novel O-typing assay can be a useful tool for epidemiologic and vaccine studies.IMPORTANCE is an important opportunistic pathogen. The gastrointestinal (GI) tract is the primary reservoir of in humans, and GI carriage is believed to be a prerequisite for invasive infection. Knowledge about the dynamics and duration of GI carriage has been hampered by the lack of tools suitable for detection and strain discrimination. Real-time PCR is particularly suited to the higher-throughput workflows used in population-based studies, which are needed to improve our understanding of carriage dynamics and the factors influencing colonization.
已成为全球健康威胁，原因是其在传播抗菌素耐药性方面的作用，以及它是医院获得性感染和新生儿败血症的常见原因。荚膜和脂多糖 (LPS) O-抗原多糖表面抗原是主要的免疫原，可用于菌株分类，也是疫苗开发的候选物。我们已经开发出用于分子血清分型、亚型和定量最常见 LPS O-抗原型（即 O1、O2、O3 和 O5）的实时 PCR 试剂。我们描述了这种 O 型分型测定的两种应用：用于筛选培养物分离株和直接对粪便样本中的 进行分型。我们发现 O 型分型测定结果与 81 株培养物分离株的全基因组测序结果完全一致，并且直接对粪便样本进行 O 型分型的结果有>90%的一致性，不一致主要是由于基于培养的比较方法的敏感性不足。此外，我们在对住院患者人群的粪便直接检测中发现了不同丰度的混合 O 型群体的证据。综上所述，这些结果表明，这种新型 O 型分型测定可以成为流行病学和疫苗研究的有用工具。
重要的是一种重要的机会性病原体。胃肠道 (GI) 是人类中 的主要储存库，并且 GI 定植被认为是侵袭性感染的先决条件。由于缺乏适合检测和菌株区分的工具，因此对 GI 定植的动态和持续时间的了解受到了阻碍。实时 PCR 特别适合于基于人群的研究中使用的高通量工作流程，这对于改善我们对定植动态和影响 定植的因素的理解是必要的。
