P1695 Late mycobacterium abscessus endocarditis, a case report

Abstract

Abstract Endocarditis due to mycobacterial pathogens is a very rare entity, linked with hospital environment and early after valve replacement, with only a few cases reported of Mycobacterium abscessus. To our knowledge, there are 13 case reports in the literature, with only one case on native valve. A 66-year old male patient, with no previous intravenous drug use, and mechanical aortic valve replacement with myocardial revascularization (posterior descendent artery) eleven years ago, presented with fever and dyspnea, transthoracic echocardiography showed a 7x5 mm-sized vegetation in the aortic prosthetic valve, and thickness in mitral-aortic fibrosa extended to mitral anterior leaflet (Panel A). Blood cultures reported fast growing mycobacteria, and microarray genetic testing revealed Mycobacterium abscessus. HIV, B and C hepatitis testing results were negative. Antibiotic therapy started with imipenem, cotrimoxazole and amikacin, and after culture guided adjustment, continued with amikacin and tygecicline. One month after, patient presented persistence of positive blood cultures and a new transthoracic echocardiography reported abscessus in mitral-aortic fibrosa (Panel B), after that finding, surgery was planned, the aortic valve was replaced by another mechanical prostheses. Patient was discharged after multiple negative blood cultures and clinical stablility. Three months after, patient presented fever, empirical antibiotic treatment was tigecicline and amikacin, blood cultures reported Mycobacterium abscessus, new transthoracic echocardiography revealed 11x8 mm-sized vegetation, and new abscessus on mitral-aortic fibrosa (Panel C). Blood cultures remain positive, and new valve replacement is decided by Heart Team with bad prognosis, after surgery patient died. Pathology department reported valve prosthesis with inflammatory infiltrate, with presence of grampositive bacilli, and positive Ziehl-Neelsen stain (Panel E,D). Non-tuberculous mycobacteria is an emergent pathogen group, with wide spectrum of infections, specially reported in lung, soft tissues and eyes, with few cases reported of cardiac disease. These pathogens showed multidrug resistance, and high mortality. The most large series report 50 patient affected with mycobacterial endocarditis, and seven caused by Mycobacterium absccesus. There are several problems regarding treatment, with a lack of consensus among it; literature suggest early susceptibility test for macrolides (clarythromicin), aminoglucosides, quinolones, cotrimoxaole, tygecicline and carbapenem antibiotic. Treatment usually involves initial combination antimicrobial therapy with macrolide plus intravenous agents for at least 2 weeks to several months followed by oral macrolide-based therapy. In vitro MIC of tygecicline are low, and the drug should also be considered in treatment regimen. Abstract P1695 Figure. Echocardiography and pathology images