Case Presentation:
A 40 year‐old male presents with fever, severe fatigue, intermittent myalgias, migratory polyarticular pain and 18 kg unintentional weight loss over 4 months. He has no prior illnesses, and his social history is notable for remote IV drug abuse 7 years ago. Prior HIV testing, PPD placement, and hepatitis serologies were negative. Physical exam showed significant wasting, poor oral hygiene, and decreased lower extremity muscle mass. He was afebrile with no cardiac murmur. Work up revealed a mild leukocytosis, slightly elevated liver enzymes, microscopic hematuria, and elevated ESR/CRP. The initial set of blood cultures identified gram‐positive cocci in pairs and chains. Trans‐thoracic echocardiogram revealed echo‐densities in the aortic valve, and subsequent trans‐esophageal echocardiogram revealed a bicuspid aortic valve with independently mobile soft‐tissue densities, consistent with endocarditis and an ascending aortic valve aneurysm. Vancomycin was empirically started and shifted to ceftriaxone once speciation showed susceptible Streptococcus salivarius. Repeat blood cultures were negative, and CT of the chest, abdomen, and pelvis was unrevealing for malignancy. He was seen by gastroenterology, infectious disease, and cardiothoracic surgery. Follow‐up plan included elective colonoscopy, followed by aortic valve and aneurysm repair. The patient was discharged home to complete a long‐term course of IV antibiotics and is currently doing well.
Discussion:
Streptococcus salivarius is a rare causative agent of infective endocarditis, with 1 study identifying only 4 out of 183 cases of endocarditis (2%) caused by Viridans streptococci to be caused by S. salivarius. It is usually found on the dorsum of the tongue as well as the pharyngeal mucosa. Our patient had a predisposition to develop native‐valve endocarditis, given his bicuspid aortic valve, and poor oral hygiene, which has also been associated with IE‐related bacteremia after toothbrushing. S. salivarius is closely related to S. bovis, and differentiating between the 2 species is important given the association between S. bovis infective endocarditis and colon malignancy. Although S. salivarius infection has been associated with colonic malignancy in a few case reports, a 16 year prospective study done in Spain did not show a significant association between S. salivarius and colon malignancy when compared with type 1 S. bovis, but did note a higher rate of non‐colon malignancy and penicillin resistance.
Conclusions:
Streptococcus salivarius is an uncommon cause of bacteremia and infective endocarditis and is not strongly associated with colon malignancy. Infection from S. salivarius usually signifies a breakdown in the mucosa along the gastrointestinal tract, as well as possible serious underlying medical condition/malignancy. Given its association with non‐colon malignancy, in the appropriate clinical setting, a workup to rule‐out malignancy is warranted.