Li Xin, Cao Huiluo, Chen Jonathan Hon-Kwan, Ng Yuey-Zhun, Fung Ka-Kin, Cheng Vincent Chi-Chung, Ho Pak-Leung
Department of Microbiology, and Carol Yu Centre for Infection, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
Department of Microbiology, Queen Mary Hospital, Hong Kong SAR, China.
Microorganisms. 2023 Mar 6;11(3):667. doi: 10.3390/microorganisms11030667.
Typhoid fever is a notable disease in Hong Kong. We noticed two local cases of typhoid fever caused by Typhi within a two-week period in late 2022, which had no apparent epidemiological linkage except for residing in the same region of Hong Kong. A phylogenetic study of Typhi isolates from Hong Kong Island from 2020 to 2022 was performed, including a whole-genome analysis, the typing of plasmids, and the analysis of antibiotic-resistance genes (ARGs), to identify the dominant circulating strain and the spread of ARGs. A total of seven isolates, from six local cases and an imported case, were identified from positive blood cultures in two hospitals in Hong Kong. Five antibiotic-sensitive strains of genotype 3.2.2 were found, which clustered with another 30 strains originating from Southeast Asia. Whole-genome sequencing revealed clonal transmission between the two index cases. The remaining two local cases belong to genotype 2.3.4 and genotype 4.3.1.1.P1 (also known as the H58 lineage). The genotype 4.3.1.1.P1 strain has an extensively drug-resistant (XDR) phenotype (co-resistance to ampicillin, chloramphenicol, ceftriaxone, ciprofloxacin, and co-trimoxazole). Although the majority of local strains belong to the non-H58 genotype 3.2.2 with a low degree of antibiotic resistance, the introduction of XDR strains with the global dissemination of the H58 lineage remains a concern.
伤寒热在香港是一种值得关注的疾病。2022年末，我们注意到在两周内出现了两例由伤寒杆菌引起的本地伤寒热病例，除了居住在香港的同一地区外，这两例病例没有明显的流行病学联系。我们对2020年至2022年从香港岛分离出的伤寒杆菌进行了系统发育研究，包括全基因组分析、质粒分型以及抗生素抗性基因（ARGs）分析，以确定主要的流行菌株和ARGs的传播情况。从香港两家医院的阳性血培养物中，共鉴定出七株分离株，分别来自六例本地病例和一例输入性病例。发现了五株基因型为3.2.2的抗生素敏感菌株，它们与另外30株源自东南亚的菌株聚在一起。全基因组测序显示两例索引病例之间存在克隆传播。其余两例本地病例分别属于基因型2.3.4和基因型4.3.1.1.P1（也称为H58谱系）。基因型4.3.1.1.P1菌株具有广泛耐药（XDR）表型（对氨苄西林、氯霉素、头孢曲松、环丙沙星和复方新诺明均耐药）。尽管大多数本地菌株属于抗生素耐药程度较低的非H58基因型3.2.2，但随着H58谱系在全球传播而引入的XDR菌株仍然令人担忧。
