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Streptobacillus moniliformis bacteremia in a rheumatoid arthritis patient without a rat bite: a case report
Takahito Nei1, Akiko Sato2, Kazunari Sonobe3,4
1Department of Infection Control and Prevention, Nippon Medical School Hospital, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ward, Tokyo, 113-8603, Japan. takahitonei@gmail.com.
Background:
Rat bite fever is a relatively rare infectious disease due to infection with Streptobacillus moniliformis or Spirillum minus mainly via directs bite by rats, mice, or other rodents. If there is no clear bite history, the diagnosis is difficult or may not be made.
Case Presentation:
A 72-year-old Asian female with rheumatoid arthritis was admitted for high grade fever and walking difficulty with severe lumbago. Initially, we suspected lumber compression fracture with deterioration of rheumatoid arthritis, but Gram-negative bacilli were isolated from blood culture during hospitalization. The isolated organism was identified as S. moniliformis by 16S ribosomal ribonucleic acid (rRNA) sequencing. S. moniliformis is well known to be a primary causative organism of rat bite fever, but this patient had no history of rat bite. Had S. moniliformis bacteremia not been detected, she might have been treated for rheumatic exacerbation.
Conclusion:
We emphasize the importance of performing appropriate microbial culture testing for identifying potential infectious diseases. We also conclude that S. moniliformis infection can become established with contaminated vehicle contact alone, not only as a direct result of a bite. We must keep mind that those working in places where rodents breed or are at risk of contact with rats or mice might be at risk for contracting this unusual disease.
Insights
Rat bite fever, caused by Streptobacillus moniliformis, can occur without a direct bite, highlighting the need for microbial testing. This unusual infection can result from contaminated vehicle contact, especially in rodent-exposed environments.
Area of Science:
- Infectious Diseases
- Microbiology
- Medical Diagnostics
Background:
- Rat bite fever is a rare zoonotic disease caused by Streptobacillus moniliformis or Spirillum minus.
- Diagnosis is challenging without a clear bite history, potentially leading to misdiagnosis of other conditions.
Observation:
- A 72-year-old female with rheumatoid arthritis presented with fever and severe back pain, initially suspected as a spinal issue.
- Blood cultures revealed Gram-negative bacilli, identified via 16S rRNA sequencing as Streptobacillus moniliformis.
Findings:
- The patient had no history of a rat bite, challenging the typical diagnosis of rat bite fever.
- Streptobacillus moniliformis bacteremia was confirmed, preventing misdiagnosis and inappropriate treatment for rheumatic exacerbation.
Implications:
- Emphasizes the critical role of microbial cultures in diagnosing obscure infectious diseases.
- Suggests that Streptobacillus moniliformis infection can arise from contaminated vehicle contact, not solely from bites.
- Highlights the risk for individuals in rodent-frequented areas to contract this uncommon infection.