Case Presentation: A 63-year-old woman with no significant medical history presented to the ED with three days of fever, confusion, and lethargy. She was responsive to physical but not verbal stimuli. Vital signs included temperature of 38.8C, heart rate of 110 BPM, blood pressure of 107/52 mmHg, with SpO2 of 94% on room air. Her WBC was 19.4 x10E3/uL with lymphocytic predominance. LP showed 26 WBC/uL with 65% PMN and 640 RBC. CSF gram stain showed many gram-positive cocci in pairs. CSF and blood cultures grew Streptococcus gallolyticus (bovis). Empiric vancomycin, ceftriaxone, acyclovir, and dexamethasone were given, which were narrowed to ceftriaxone. 14 days of therapy were given. Echocardiogram was performed and was without cardiac valvular vegetations. The etiology of S. bovis was presumed secondary to a GI source as the TEE was negative. Colonoscopy was recommended as an outpatient. Her course was complicated by hypoxemic respiratory failure requiring ICU stay, as well as diffuse muscular weakness. By the time of discharge, she had near complete recovery.
Discussion: S. bovis can cause bacteremia, meningitis, and endocarditis (1). It is present in the GI tract of up to 15% of healthy individuals and up to 55% of patients with inflammatory bowel disease or colon cancer (2). It is thought that inflammation/cancer jeopardize the GI mucosal barrier and allow the bacteria to reach the blood stream (2). There is a well-known association between S. bovis and colorectal cancer, and this association is frequently emphasized in medical education. However, the International Collaboration on Endocarditis-Prospective Cohort study showed that out of 2781 patients with endocarditis, approximately 6% were related to S. bovis (3). Among patients with S. bovis bacteremia, there is a 25-50% incidence of endocarditis (1). S. bovis endocarditis more often affects older patients with medical co-morbidities (1). Therefore it is important to maintain a high degree of suspicion for endocarditis in patients who are found to have S. bovis bacteremia (1). Given that the incidence of this disease is low, it is appropriate to take a typical approach to endocarditis with TTE followed by TEE if there is further suspicion.
Conclusions: The risk of endocarditis in cases of S. bovis bacteremia may be underrecognized. Though S. bovis meningitis is a rare disease, S. bovis bacteremia is more commonly seen in hospitalized patients. It is important for hospitalists to be aware of the risk of endocarditis as well as the association of GI malignancy with S. bovis bacteremia. Consultation with specialty services can be instrumental in identifying cardiac or intestinal disease in these patients. Data on the best treatment strategy for patients with S. bovis bacteremia is limited, but in the absence of endocarditis, a two-week course of IV penicillin or ceftriaxone has been shown to be effective (4).
References:
1. Fitzmaurice GJ et al., Streptococcus bovis bacteraemia: an evaluation of the long-term effect on cardiac outcomes. Gen Thorac Cardiovasc Surg 2014
2. Mello R et al., Streptococcus bovis endocarditis: analysis of cases between 2005 and 2014. Braz J Infect Dis 2015
3. Murdoch DR et al., Clinical presentation, etiology, and outcome of infective endocarditis in the 21st century: the International Collaboration on Endocarditis-Prospective Cohort Study. Arch Intern Med 2009
4. Cohen LF et al., Streptococcus bovis Infection of the Central Nervous System: Report of Two Cases and. Source Clin Infect Dis 1997