Pasteurella multocida Endocarditis with Septic Arthritis: Case Report and Review of the Literature

Background: There is a paucity of evidence regarding optimal management of Pasteurella spp. endocarditis. The authors report the first case of Pasteurella spp. endocarditis with septic arthritis and review the literature. Case Description: A 79-year-old patient with significant comorbidities, including prosthetic aortic valve, was admitted with left knee swelling, fever, and confusion, having been scratched by a cat 2-weeks prior. At presentation, there was a metallic click, a Grade 3 pan-systolic murmur and Grade 1 flow murmur audible on auscultation. Blood and synovial fluid cultures both isolated Pasteurella multocida, identified by matrix-assisted laser desorption ionisation–time of flight, which was sensitive to penicillin according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST); minimum inhibitory concentration: 0.094). The patient underwent joint washout and received intravenous piperacillin/tazobactam for 3 days before switching to benzylpenicillin once sensitivities were known. Due to continued pyrexia, a transthoracic echocardiogram was obtained, which revealed a small mobile mass on a thickened mitral valve suspicious for a vegetation. On review by the Infective Endocarditis team, conservative management was deemed best, given the presence of comorbidities. Despite requiring further joint washout due to persistent knee pain, the patient was successfully treated with 8 weeks of antibiotic therapy (24 days of benzylpenicillin monotherapy, 2 weeks of benzylpenicillin and ciprofloxacin, and 15 days ciprofloxacin monotherapy). Discussion: Previous literature reviews report a higher mortality of Pasteurella spp. endocarditis when managed without cardiac surgery, thus recommending surgery in all cases. The authors found these to have confounding factors, including inadequate duration of antimicrobials, aortic root abscess, and rapid progression to death. The authors’ case of Pasteurella spp. endocarditis, complicated by septic arthritis, showed successful therapy without cardiac surgery.