Tissierella praeacuta Bacteremia Associated With Acute on Chronic Osteomyelitis: A Case Report.

Tissierella praeacuta is a rare gram-variable bacillus that naturally occurs in the environment and is pathogenic in humans with chronic infections. We report the case of a 45-year-old man with a history of chronic osteomyelitis of the left tibia and recurrent bacteremia secondary to intravenous drug use (IVDU). He had previously received multiple partially completed courses of antibiotics over the past one year. Blood cultures demonstrated polymicrobial infection, including T. praeacuta and methicillin-sensitive Staphylococcus aureus managed with parenteral beta-lactams, and the subsequent first surveillance cultures remained sterile. Medical literature on human infections with T. praeacuta is limited due to its rare occurrence. Most cases have reported sensitivity to beta-lactam antibiotics, making them an antibiotic of choice. T. praeacuta infections should prompt a search for additional underlying infectious foci and treatment of any additional co-infecting microbes.