S3808 From Blood Culture to Colon Investigation: Streptococcus gallolyticus as a Marker for Colorectal Neoplasia

Introduction: Streptococcus gallolyticus composes the natural flora of the gastrointestinal tract. A rare cause of infection, Streptococcus gallolyticus bacteremia has an annual incidence of 2 per 100,000. Bacteremia associated with this species is typically attributed to translocation of colonic flora into the bloodstream, usually in the setting of colorectal neoplasia. We present a case of a patient with Streptococcus gallolyticus bacteremia found to have a colonic mass. Case Description/Methods: A 92-year-old with a past medical history of prostate cancer with bony metastases, chronic obstructive pulmonary disease, coronary artery disease, and right hip fracture presented to the hospital for hypotension. He endorsed chronic nausea, poor oral intake, and constipation. Mean arterial pressure <65 mmHg necessitated admission to the ICU with administration of pressors and IV fluid rehydration. Blood cultures grew Streptococcus gallolyticus and he was treated with ceftriaxone for septic shock. Initial computed tomography (CT) of the chest found subsegmental pulmonary embolism of the right middle lobe and CT abdomen found a large colonic stool burden. Transthoracic echocardiogram revealed tricuspid valve vegetations concerning for endocarditis. There was a suspicious right hip abscess on exam, leading to a CT of the right hip which revealed a heterogeneously enhancing 5.5 cm mass in the sigmoid colon, highly concerning for primary malignancy—a finding that was not detected on prior imaging. Upon further discussion of goals of care with the patient’s family, the patient was eventually discharged to a long-term care facility for in-patient hospice care. Discussion: Patients with atypical bacteremia warrants further investigation. In this case, Streptococcus gallolyticus bacteremia was detected. A relatively uncommon pathogen that is typically treated with ceftriaxone, Streptococcus gallolyticus is the primary species of the group known as Streptococcus bovis. This species has a strong association with colorectal cancer and endocarditis, with Streptococcus gallolyticus bacteremia associated with a 70% coincidence of colorectal neoplasia and odds ratios ranging from 5 to 7 compared to control groups. Detection of our patient’s colonic mass was obfuscated by notable constipation on initial CT abdomen, only detected on repeat imaging. Clinicians should have a high index of suspicion for colorectal neoplasia in patients with concomitant endocarditis and Streptococcus gallolyticus bacteremia.