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[Polymicrobial endocarditis: a clinical and evolutive study of 12 cases diagnosed during a 10-year period]
M E Valencia Ortega1, A Enríquez Crego, J Guinea Esquerdo
1Servicio de Enfermedades Infecciosas, Centro de Investigación Clínica, Instituto de Salud Carlos III, Madrid.
Abstract:
Polymicrobial endocarditis (PE) is uncommon, whether in series of cases of polymicrobial bacteriemia or of endocarditis. Among the 201 cases of infective endocarditis seen between 1986 and 1995 by an infectious diseases service, 12 patients had PE (6%). Nine were males, mean age was 28 years and ten were active intravenous drug users. All of them were HIV (+) and 50% had AIDS. Eleven subjects had infection of the tricuspid valve and 58% developed septic pulmonary emboli. The most common organism encountered was Staphylococcus aureus in 8 patients followed by Streptococcus viridans and S. pneumoniae in three. The most common combinations of organisms were S. aureus and S. pneumoniae in 3 cases and S. aureus and Pseudomonas aeruginosa in two. Two patients died, one with Xantomona maltophilia and another with Candida albicans. The symptoms of PE were usually indistinguishable from endocarditis caused by a single organism and the prognosis depended on the species rather than the number of organisms isolated.
Insights
Polymicrobial endocarditis (PE) is rare, often affecting young, HIV-positive intravenous drug users, particularly impacting the tricuspid valve. Prognosis in PE depends on the specific microbes involved, not their quantity.
Area of Science:
- Infectious Diseases
- Cardiology
- Microbiology
Background:
- Polymicrobial endocarditis (PE) is an uncommon condition.
- It is frequently observed in specific patient populations, including intravenous drug users and those who are HIV-positive.
- Symptoms are often indistinguishable from those of monomicrobial endocarditis.
Purpose of the Study:
- To investigate the characteristics and outcomes of polymicrobial endocarditis.
- To identify common causative organisms and risk factors associated with PE.
- To determine factors influencing the prognosis of PE.
Main Methods:
- Retrospective case series analysis of infective endocarditis (IE) cases.
- Infectious diseases service data from 1986-1995.
- Clinical data review including patient demographics, risk factors, affected valves, complications, and microbiological findings.
Main Results:
- 12 out of 201 IE cases (6%) were diagnosed with PE.
- The majority of PE patients were young males (mean age 28), active intravenous drug users, and HIV-positive (50% with AIDS).
- The tricuspid valve was most commonly infected (11 patients), with 58% experiencing septic pulmonary emboli. Staphylococcus aureus was the most frequent organism, often in combination with other bacteria like Streptococcus pneumoniae or Pseudomonas aeruginosa. Two deaths occurred, associated with Xanthomonas maltophilia and Candida albicans.
Conclusions:
- Polymicrobial endocarditis is a distinct entity within infective endocarditis, predominantly seen in a specific high-risk demographic.
- Tricuspid valve involvement and septic pulmonary emboli are significant complications.
- The species of microorganisms, rather than the number, is the critical determinant of patient prognosis.