Rat bite fever is a rare systemic illness, with a mortality rate of about 13% without treatment. It is caused by infection with Streptobacillus moniliformis, a gram-negative bacillus. Infection can result from a bite or scratch from an infected or colonized rat, or from handling rats at home or the workplace.

We describe a case of rat bite fever in a 46-year-old healthy lady which was transmitted without a history of being bitten or scratched. With prompt liaison with local microbiologists we grew Streptobacillus moniliformis from both blood and synovial fluid for the first time. Our case was complicated by septic arthritis despite treatment with appropriate antibiotics.