Concurrent Bacteremia and Severe Fever With Thrombocytopenia Syndrome: A Report of Two Cases

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral hemorrhagic fever caused by the severe fever with thrombocytopenia syndrome virus (SFTSV). This virus, which is transmitted through ticks, is prevalent in Asian countries, including Japan. This report describes two rare cases of SFTS with concurrent bacteremia. In the first case, a 73-year-old Japanese man presented with fever and coagulopathy and subsequently developed oral mucosal hemorrhage and bloody stools. Initial tests showed thrombocytopenia and leukopenia. Blood cultures on admission revealed Enterococcus faecalis bacteremia, and SFTSV co-infection was subsequently confirmed by polymerase chain reaction (PCR). He was treated with vancomycin, followed by ampicillin, and recovered. In the second case, a 70-year-old Japanese man presented with fever and diarrhea and subsequently developed renal impairment and thrombocytopenia. Blood cultures on admission revealed Escherichia coli bacteremia, and SFTSV co-infection was subsequently confirmed by PCR. He was treated with ceftriaxone, followed by ampicillin, and recovered. We conducted a literature search to look for evidence of a link between SFTS and bacteremia. Further epidemiological studies on the association between SFTS and bacteremia are warranted to provide an understanding of the pathogenic mechanisms.