The Association ofStreptococcus gallolyticusSubspeciespasteurianusBacteremia with the Detection of Premalignant and Malignant Colonic Lesions

Abstract

Streptococcus gallolyticussubspecies (subsp.)gallolyticus(formerlybovisbiotype I) bacteremia has been associated with colonic adenocarcinoma. Thebovisspecies underwent reclassification in 2003. Subtypes ofgallolyticusare associated with colonic malignancy but are less frequent, resulting in less awareness. A 71-year-old male admitted with worsening lower back pain and fevers. Initial vital signs and laboratory data were within normal limits. MRI revealed lumbosacral osteomyelitis and antibiotics were initiated. Blood cultures showedStreptococcusspecies, prompting a transesophageal echocardiogram (TEE) revealing vegetations on the mitral and aortic valves. The etiology for his endocarditis was unclear. A colonoscopy was suggested, but his clinical instability made such a procedure intolerable. Final cultures revealedStreptococcus gallolyticussubsp.pasteurianus(previouslybovisbiotype II). After antibiotic completion he underwent aortic grafting with valve replacements. Later, he was readmitted forStreptococcusbacteremia. After a negative TEE, colonoscopy revealed a 2.5 × 3 cm cecal tubulovillous adenoma with high-grade dysplasia suspicious for his origin of infection. Clinicians understand the link betweenStreptococcus gallolyticussubsp.gallolyticus(bovistype I) and malignancy, but the new speciation may be unfamiliar. There are no guidelines for managingS. gallolyticussubsp.pasteurianusbacteremia; therefore a colonoscopy should be considered when no source is identified.