Rat bite fever: a case report review

Acta Clin Belg. 2022 Oct;77(5):883-888. doi: 10.1080/17843286.2021.1992940. Epub 2021 Oct 21.


Context: Rat bite fever is a rare disease with a challenging differential diagnosis. The zoonosis has a potentially lethal course in a vulnerable population (children and low socioeconomic class) and a commonly available standard therapy (penicillin). This case report review outlines common epidemiological and clinical factors to improve clinical awareness and timely response to therapeutic actions.

Methods: A systematic literature review was conducted in the PubMed database looking for English language European case reports of rat bite fever from 2000 to 2021.

Results: In 17 out of 20 selected cases, the condition of the index patient was identified as an infectious syndrome. Thanks to the almost omnisensitive susceptibility pattern of Streptobacillus moniliformis, timely antibiotic administration prevented an unfavorable outcome in all these cases. However, in the three remaining cases, the initial diagnoses were arthritis (on autoimmune basis and gout) and viral syndrome. Due to delayed antibiotic administration, one case suffered persistent harm, while the other two cases encountered prolonged illness.

Conclusion and recommendations: Rat bite fever is a diagnosis that can be easily missed from both a clinical and a microbiological point of view. As such, rat bite fever becomes part of the differential diagnosis whenever a patient presents with a fever syndrome after being in contact with rodents. In the case of persistent fever, blood culture sampling should be performed even in the absence of a systemic inflammatory response. A bacterial 16S ribosomal RNA PCR on blood or joint aspiration (cultures) is an even more sensitive diagnostic test. Since most transmissions occurred in a domestic setting, keeping rats as pets cannot be recommended.

Keywords: Rat bite fever; Streptobacillus moniliformis; streptobacillosis.

Publication types

  • Case Reports
  • Systematic Review

MeSH terms

  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Humans
  • Penicillins
  • RNA, Ribosomal, 16S / genetics
  • Rat-Bite Fever* / diagnosis
  • Rat-Bite Fever* / drug therapy
  • Rat-Bite Fever* / microbiology
  • Rats
  • Streptobacillus* / genetics
  • Zoonoses


  • Anti-Bacterial Agents
  • Penicillins
  • RNA, Ribosomal, 16S