Sydney Institute for Infectious Diseases, The University of Sydney, Westmead, New South Wales, Australia.
Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia.
PLoS One. 2023 Aug 23;18(8):e0289070. doi: 10.1371/journal.pone.0289070. eCollection 2023.
Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever and, in some cases, chronic carriage after resolution of acute disease. This study examined sequential isolates of S. Typhi from a single host with persistent asymptomatic infection. These isolates, along with another S. Typhi isolate recovered from a household contact with typhoid fever, were subjected to whole genome sequencing and analysis. In addition, direct sequencing of the bile fluid from the host with persistent infection was also performed. Comparative analysis of isolates revealed three sub-populations of S. Typhi with distinct genetic patterns. Metagenomic sequencing recognised only two of the three sub-populations within the bile fluid. The detection and investigation of insertion sequences IS10R and associated deletions complemented analysis of single nucleotide polymorphisms. These findings improve our understanding of within-host dynamics of S. Typhi in cases of persistent infection and inform epidemiological investigations of transmission events associated with chronic carriers.
肠炎沙门氏菌血清型 Typhi（S. Typhi）可引起伤寒，在某些情况下，急性疾病痊愈后会持续无症状携带。本研究检测了来自单一宿主的持续无症状感染的 S. Typhi 连续分离株。这些分离株与从伤寒家庭接触者中恢复的另一个 S. Typhi 分离株一起进行了全基因组测序和分析。此外，还对持续感染宿主的胆汁进行了直接测序。对分离株的比较分析显示，S. Typhi 有三个具有不同遗传模式的亚群。宏基因组测序仅在胆汁中识别出三个亚群中的两个。插入序列 IS10R 的检测和调查以及相关缺失补充了单核苷酸多态性分析。这些发现提高了我们对持续性感染情况下 S. Typhi 宿主内动态的理解，并为与慢性携带者相关的传播事件的流行病学调查提供了信息。
