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Volume 8, Issue 3

A case of laboratory-acquired Typhi infection due to phage typing in Japan: whole-genome sequencing confirms the source of infection Open Access

Abstract

Typhoid fever, caused by serovar Typhi, is a systemic infection. Approximately 40 cases occur annually in Japan, most of which are imported. In August 2023, a researcher engaged in phage typing of . Typhi was diagnosed with typhoid fever.

A 48-year-old man presented with high fever, diarrhoea, malaise and loss of appetite. Initial findings, including liver dysfunction and severe inflammation, led to a suspected diagnosis of autoimmune disease. However, blood cultures identified . Typhi, confirming typhoid fever. Comparative genomic analysis demonstrated clonality between the strain handled in the laboratory and the patient isolates, indicating a laboratory-acquired infection.

This case underscores the need for ongoing vigilance regarding the risk of laboratory-acquired infections and highlights the value of whole-genome sequencing for tracking. It would be also emphasized that this is the first reported case in Japan linked to phage typing, a conventional typing method for . Typhi. This raises the urgency of transitioning from phage typing to genotyping and recommends mandatory typhoid vaccination for laboratory personnel working with . Typhi to minimize infection risk.

  • Received:
  • Accepted:
  • Published Online:
Keyword(s): laboratory-acquired infection , phage typing and Salmonella Typhi
Funding
This study was supported by the:
  • Japan Agency for Medical Research and Development (Award JP24wm0225023)
    • Principal Award Recipient: MasatomoMorita
  • Japan Agency for Medical Research and Development (Award JP24fk0108663)
    • Principal Award Recipient: HidemasaIzumiya
  • Japan Agency for Medical Research and Development (Award JP24fk0108683)
    • Principal Award Recipient: YukihiroAkeda
© 2026 The Authors
  • This is an open-access article distributed under the terms of the Creative Commons Attribution License.
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2026-03-13
2026-04-11

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/content/journal/acmi/10.1099/acmi.0.001121.v4
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A case of laboratory-acquired Salmonella Typhi infection due to phage typing in Japan: whole-genome sequencing confirms the source of infection
Access Microbiology 8, 001121.v4 (2026); https://doi.org/10.1099/acmi.0.001121.v4
/content/journal/acmi/10.1099/acmi.0.001121.v4
/content/journal/acmi/10.1099/acmi.0.001121.v4
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