Fusobacterium nucleatum endocarditis: a case report and literature review.

Am J Cardiovasc Dis 2023;13(1):29-31 www.AJCD.us /ISSN:2160-200X/AJCD0146869 Case Report Fusobacterium nucleatum endocarditis: a case report and literature review Deepak Dhaliwal1, Rishi Bhargava1, Mohammad Reza Movahed2,3 1 3 CareMore Health, Tucson, Arizona, USA; 2University of Arizona Server Heart Center, Tucson, Arizona, USA; Department of Medicine, University of Arizona, Phoenix, Arizona, USA Received October 7, 2022; Accepted February 5, 2023; Epub February 15, 2023; Published February 28, 2023 Abstract: Fusobacteria is anaerobic gram-negative rods, which frequently colonize the oral cavity and can rarely cause deadly diseases in humans. The two most commonly found in this group of bacteria are fusobacterium necrophorum and fusobacterium nucleatum. Only a handful of cases of endocarditis due to fusobacterium have been reported. We describe an 86-year-old male who had a recent tooth extraction presenting to the emergency department with weakness lightheadedness, and pain in his right elbow. He had a low-grade fever of 100.8°. The patient was discharged home but came back less than 24 hours with a fever of 102° and chills and again after the second discharge with sepsis of unknown origin. A week after initial blood cultures were drawn, fusobacterium nucleatum grew in one of two sets and his transesophageal echocardiogram revealed vegetation on his mitral valve. The patient was then successfully treated with a six weeks course of ampicillin-sulbactam. This case is followed by a review of the literature. Keywords: Endocarditis, bacterial endocarditis, Fusobacteria bacteremia Introduction Fusobacteria is anaerobic gram-negative rods that frequently colonize the oral cavity [1, 2], but can cause rare and deadly diseases in humans if enters into the bloodstream. The two most commonly found in this group of bacteria are fusobacterium necrophorum and fusobacterium nucleatum [3]. While males appear to be more affected by fusobacterium bacteremia in general, Necrophorum is linked closely with a younger population without comorbidities under 30 years of age. On the other hand, nucleatum has been found to occur in the elderly, especially with the comorbidities of malignancy and dialysis [4, 5]. Fusobacterium has been found to cause periodontal disease, Lemierre syndrome, meningitis, abscesses in different organs, adverse pregnancy outcomes, and various other human diseases. Tonsillitis can be followed by septic thrombophlebitis of the internal jugular vein and then septicemia with septic emboli in the lungs and other sites that can cause life-threatening conditions. Only a handful of cases of endocarditis due to fusobacterium have been reported [6]. The majority of cases of endocarditis are com- prised of Streptococcus and Staphylococcus species. Enterococcus, pseudomonas, Neisseria, and the HACEK group, which comprises of haemophilus, actinobacillus, cardiobacterium, eikenella, and kingella are the other well-recognized bacterial organisms that cause endocarditis. It is important to recognize Fusobacterium as a potential cause of endocarditis when evaluating a patient with fusobacterium bacteremia as under treatment can be fatal. Case report The patient was an 86-year-old male with a past medical history of chronic atrial fibrillation, pacemaker insertion, diabetes mellitus type 2, dyslipidemia, and coronary artery disease with h/o coronary bypass surgery. He had a recent tooth extraction presenting to the emergency department with vague symptoms of weakness in his lower extremities, lightheadedness, and on-and-off pain in his right elbow for a few days. A basic workup at that time did not reveal any significant abnormalities other than a low-grade fever of 100.8°. The patient was given IV fluids and discharged home. The patient returned to the ER within less than 24 hours after being dis- Fusobacterium nucleatum endocarditis antibiotic treatment. Repeat echo 4 weeks after discharge did not show any significant mitral valve abnormality. Discussion and review Figure 1. Transesophageal echocardiogram showing vegetation on the mitral valve. LA = Left atrium, L = Left ventricle, MV = mitral valve. charged with a fever of 102° and chills. The workup again was essentially negative for any focal infection except for hematuria in his urine and an ill-defined 3.2 cm hypoattenuating lesion in the right hepatic lobe on a computer tomography test of his chest, abdomen, and pelvis without contrast. Again, the patient was sent home but returned a third time two days later with high-grade fevers with a max of 104°. Labs demonstrated neutropenia with a WBC of 2.5, lactic acid of 2.2, thrombocytopenia with platelets of 115, elevated liver enzymes with AST-113, ALT-79, and ALP-131, all of which were in the normal range on his labs two days prior. He was admitted for sepsis of unknown origin and started on vancomycin and piperacillin-sulbactam after blood cultures were obtained. Ultrasound of the liver was highly suggestive of an abscess for which a drain was placed by a Radiologist. The patient continued to spike fevers, have pain in his right elbow that was warm and red without a palpable mass, and have negative blood cultures. Repeat imaging showed that his liver abscess remained stable. A week after initial blood cultures were drawn, fusobacterium nucleatum grew in one of two sets. The transthoracic echocardiogram was unremarkable. Given the suspicion of possible septic emboli, a transesophageal echocardiogram was done revealing a 0.6 cm × 0.6 cm vegetation on the anterior portion of the mitral valve (Figure 1). The patient was then successfully treated with a six-week course of ampicillin-sulbactam based on the cultural sensitivity and his hepatic drain was discontinued after 2 weeks. The patient recovered and remained asymptomatic after a full course of 30 Fusobacterium is a rare cause of bacteremia and an overlooked cause of endocarditis. The patient above presented with fevers, one positive blood culture for fusobacterium nucleatum, and concern for septic emboli given his liver abscess and reoccurring joint pain. High clinical suspicion for possible endocarditis warranted a transthoracic and transesophageal echocardiogram, which later demonstrated mitral valve endocarditis. Without this investigation, the patient would have been undertreated with only 2 weeks of iv antibiotics with the hepatic abscess being labeled the primary source of the infection. The understanding of the complications that occur with fusobacterium organisms is limited given the infrequent cases that are encountered. In an 11-year retrospective study at Calgary Zone of Alberta Health Services (AHS) in Canada, 72 cases of Fusobacterium bacteremia (55 per 100,00 population) were identified with a 10% mortality rate, of which more than half of those deaths were caused by fusobacterium nucleatum [7]. A third of these cases of bacteremia had no focal source of infection. Intrabdominal, hematologic, and obstet (...truncated)