INTRODUCTION: Group B Streptococcus (GBS) is a gram-positive organism that is rarely associated with disease in adults. It is a rare cause of infective endocarditis (IE).
CASE PRESENTATION: A 27-year-old male presented with complaints of high-grade fever for one month. It was associated with cough and right-sided pleuritic chest pain for a week. He denied any recent travel, sick contact, weight loss, rash, joint pains, urinary or bowel complains. His last HIV testing was negative six months ago. His past medical history was significant for a childhood murmur for which he had required antibiotic prophylaxis before any invasive procedures, although he denied any surgeries, recurrent childhood infections or pneumonias. He presented to the emergency room with fever of 38 degree Celsius. His Pulse was 110 per minute. Other vital signs were normal. On examination he had a pansystolic murmur heard at the apex and radiating to the axilla. Respiratory examination revealed decreased breath sounds on right hemithorax. The chest X-ray showed right pleural effusion. He was started on broad-spectrum antibiotics and a chest tube was placed for drainage of the fluid. On day 2, blood cultures were positive for streptococcal agalactiae. A transesophageal echocardiogram was performed that showed a 1.5 cm mobile vegetation on the atrial side of anterior mitral valve leaflet with moderate to severe mitral regurgitation (Figure 1), a membranous ventricular septal defect (VSD) with left to right shunt and a 2.5 cm vegetation on the right ventricular side of VSD (Figure 2). His ejection fraction was estimated to be 50%. He was continued on intravenous antibiotics and repeat cultures were negative. He remained afebrile and was discharged to finish 8 weeks of antibiotics at home. He underwent elective mitral valve replacement surgery and VSD repair after 2 months. Interestingly he was found to have an atrial septal defect during surgery that was also repaired.
DISCUSSION: Group B Streptococcal endocarditis is acute in onset and is associated with large vegetations. The large vegetations and frequent emboli have been attributed to lack of fibrinolysin in streptococcus agalactiae. The mortality rates of GBS endocarditis have decreased to 20% with the combination of surgery and medical treatment as opposed to 40-50% with medical therapy alone(1). This decrease is also attributed to earlier diagnosis with the help of transesophageal echocardiography and better surgical techniques. Streptococcus agalactiae are generally more resistant to penicillin than other streptococcus strains requiring an addition of aminoglycoside during the first two weeks of antimicrobial therapy.(1) Due to this and the fulminant nature of this infection, the current antibiotic therapy recommended for streptococcus agalactiae endocarditis is penicillin G or ceftriaxone for 4-6 weeks plus gentamicin for the first two weeks. (2) Our patient had lobar pneumonia on presentation likely preceding the development of endocarditis involving the mitral valve and right ventricular side of ventriclular septal defect. He was started on penicillin and aminoglycoside for 2 weeks followed with penicilllin for 6 weeks. He responded and repeat cultures were sterile.
CONCLUSIONS: Our patient presented with GBS endocarditis involving both sides of the heart, a case not so far reported in the medical literature. A case of streptococcus agalactiae vegetation adherent on VSD orifice is also not known. In cases with small VSD the turbulent jet of blood disrupts the endocardium and thus the bacteria can stick easily to this injured area, and cause endocarditis.
Reference #1 Gallagher PG, Watanakunakorn C. Group B streptococcal endocarditis: report of seven cases and review of the literature, 1962-1985. Rev Infect Dis1986 Mar-Apr;8(2):175-88.
Reference #2 Wilson WR. Antibiotic treatment of infective endocarditis due to viridans streptococci, enterococci, and other streptococci. Clin Microbiol Infect1998;4 Suppl 3:S17-S26.
DISCLOSURE: The following authors have nothing to disclose: Ankur Lodha, Mehandi Haran, Adnan Sadiq, Jacob Shani
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