Staphylococcus saprophyticus native valve endocarditis possibly originating from the lower gastrointestinal tract

Staphylococcus saprophyticus is a common pathogen associated with uncomplicated urinary tract infection in young women and commonly colonizes in the lower gastrointestinal tract as commensal bacterium. Bacteremia or infective endocarditis caused by S. saprophyticus has rarely been reported, and in almost all cases reported of bacteremia, it originated from the urinary tract or intravascular catheter-related infections. Herein, we report the case of a 77-year-old woman diagnosed with S. saprophyticus native bivalve endocarditis. Interestingly, blood and resected valve tissue cultures revealed positive results, whereas urine culture revealed negative results. There was no evidence of any portal of entry, including the urinary tract or vascular catheter; the lower gastrointestinal tract was strongly suspected as the portal of entry, considering that her symptoms developed suddenly after undergoing a polypectomy procedure. After admission, she underwent valve replacement surgery followed by 6 weeks of antimicrobial therapy and recovered completely. This case demonstrates that the lower gastrointestinal tract can be the source of S. saprophyticus bacteremia.