J Thorac Cardiovasc Surg 1994;107:1167-1168
© 1994 Mosby, Inc.
Fortuitous detection of prosthetic valve endocarditis caused by an uncommon etiologic agent
Claudio Zussa, MDa,
Paolo Ius, MDa,
Francesco Cesari, MDa,
Carlo Valfré, MDa,
Oscar Totis, MDb
Cardiac Surgerya
Carlo Canova, MDc,
Paolo Pugina, MDd
Cardiologyc
Microbiologyd Departments
Rovigo Regional Hospital
43100 Rovigo, Italy
To the Editor:
We wish to report a case of prosthetic valve endocarditis that is unusual because of its fortuitous detection and uncommon etiologic agent, Veillonella alcalescens. To our knowledge, only three previous cases of endocarditis caused by this agent have been reported. 
1-3
A 51-year-old male patient with a history of rheumatic heart disease, who had mitral valve replacement with a Pericarbon pericardial bioprosthesis (Sorin Biomedica, Saluggia, Italy) 59 months before, was examined by two-dimensional echocardiography at our outpatient department according to the protocol of clinical evaluation of this new bioprosthesis. The clinical history after the operation had been unremarkable and no predisposing factors for endocarditis could be detected except for an asymptomatic cholelithiasis. The echocardiographic examination showed a trivial (7 mm Hg mean) prosthetic gradient with a mobile mass (2 x 1 cm) arising from the posterior mitral anulus (Fig. 1). The patient was admitted to the referring cardiology department to complete the diagnosis. He became mildly febrile (37.6° C) while waiting for the results of nine blood cultures taken during a period of 36 hours. Veillonella alcalescenswas isolated in pure culture from eight of the nine blood samples; the strain was susceptible to many antibiotics. Therapy with penicillin G at 20 million units daily was instituted. After 72 hours, two-dimensional echocardiographic examination showed the vegetations to be significantly larger, with a mean prosthetic gradient of 15 mm Hg; the patient was still febrile (37.6° C). A reoperation was therefore scheduled for the following day. Early in the morning, the patient had an embolic event at the left humeral artery, which was successfully treated by embolectomy before the cardiac operation. Once the left atrium was reopened, the bioprosthesis appeared normal but extensive rough vegetations rose from the valve anulus. A small annular excavation could be detected without any paravalvular leak. The prosthesis was replaced with a Bicarbon bileaflet mechanical prosthesis (Sorin Biomedica). Cultures from excised materials showed no growth, as did blood cultures taken in sets of four daily every week until 15 days after the antibiotic therapy (penicillin G at 10 million units every 6 hours for 6 weeks) was discontinued. The patient recovered uneventfully, with no signs of infection recurrence 14 months after the operation.
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Fig. 1. Transesophageal echocardiogram shows the vegetation (arrow)arising from the prosthetic valve anulus. LA, Left atrium; AO, aorta; RV, right ventricle; LV, left ventricle.
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The mode of detection and the etiologic agent make this case unusual. Indeed, it is not common that a patient with clear echocardiographic evidence of valvular vegetations could be completely free of symptoms and have unremarkable anamnesis. This may be explained with the singular agent, Veillonella alcalescens, an anaerobic gram-negative coccus that is a constituent of the normal flora of the upper respiratory tract, mouth, gastrointestinal tract, urinary tract, and vagina. Veillonellaspecies have been isolated in cases of osteomyelitis, 4,5 pleuropulmonary infections, 6 sinusitis, 7 and only three reported cases of endocarditis, one of which occurred after mitral valve replacement. 3 These bacteria show susceptibility to many commonly used antibiotics, such as penicillin, clindamicin, erythromycin (Erythrocin), cephalosporins, and tetracycline. The organism in our case showed resistance to metronidazole. In the presence of a valve- or prosthesis-connected mass, we believe it is justified to exclude endocarditis with accurate microbiologic evaluation before diagnosing aseptic thrombosis. Moreover, because in these cases the clinical manifestations may be vague 2 or completely absent despite the presence of incidentally detected huge vegetations (as in our case), we also suggest research for anaerobic bacteria in cases of suspected endocarditis in which the etiologic agent is difficult to isolate.
References
-
Loews L, Rosenblatt P, Alture-Werber E. A refractory case of subacute bacterial endocarditis due to Veillonella gazogenesclinically arrested by a combination of penicillin, sodium para-aminophippurate, and heparin. Am Heart J 1946;32:327-38.
-
Greaves WL, Kaiser AB. Endocarditis due to Veillonella alcalescens. South Med J 1984;77:1211-2.[Medline]
-
Loughrey AC, Chew EW. Endocarditis caused by Veillonella dispar. J Infect 1990;21:319-21.[Medline]
-
Borchardt KA, Baker M, Gelber R. Veillonella parvulasepticemia and osteomyelitis. Ann Intern Med 1977;86:63-4.
-
Barnhart RA, Weitekamp MR, Aber RC. Osteomyelitis caused by Veillonella. Am J Med 1983;74:902-4.[Medline]
-
Bartlett JG, Finegold SM. Anaerobic pleuropulmonary infections. Medicine 1972;51:413-50.[Medline]
-
Fredrich J, Brande A. Anaerobic infections of the paranasal sinuses. N Engl J Med 1974;290:135-7.
