Brewer’s Yeast as a cause of infective endocarditis

• Published in: Access microbiology 2020-02, Vol.2 (2)
• Main Authors: Hammond, Robert, Aggarwal, Dinesh, Hurt, Will, Ferran, Elena, Satta, Giovanni, Abbara, Aula
• Format: Article
• Language: English
• ISSN: 2516-8290; 2516-8290
• DOI: 10.1099/acmi.fis2019.po0037

Background: Molecular tests are increasingly used in culture negative endocarditis and may be helpful adjuncts to diagnosis; here we report the case of Saccharomyces cerevisiae mitral valve endocarditis in an immunocompetent patient. Case History: A previously well 63 year old man presented with a ten day history of fever, nights sweats and progressive shortness of breath. On arrival, he was in acute respiratory distress, in pulmonary oedema and had a pansystolic murmur. A transoesophageal echocardiogram showed severe mitral regurgitation and a mass on the posterior leaflet of the mitral valve. He was treated for a presumed native valve endocarditis with Amoxicillin, Flucloxacillin and Gentamicin. He had a minimally invasive mitral valve repair; a vegetation was noted. All initial cultures and serologies were negative. He improved and was discharged on ceftriaxone and doxycycline on OPAT. Results three weeks post-surgery showed a Beta D Glucan of >500pg/mL (cut off 80) and an 18S PCR on the valve positive for Saccharomyces cerevisiae . No histology was available from the vegetation and fungal cultures were negative. He was much improved at that point and received 6 weeks of voriconazole to treat invasive infection; his Beta D Glucan fell to less than 30 and he was well on follow-up. Conclusion: Saccharomyces cerevisae is an unusual cause of an endocarditis in an immunocompetent patient. This case illustrates the importance of considering non-bacterial causes of endocarditis in such cases and the utility of molecular diagnostics as adjuncts to traditional culture techniques.