Successful treatment of Candida parapsilosis and Pseudomonas aeruginosa infection using medical and surgical management in an injecting drug user with mitral and aortic valve endocarditis: a case report

INTRODUCTION: Polymicrobial endocarditis is a well-recognized problem in intravenous drug users and it accounts for 1 to 3% of endocarditis cases overall and up to 9% in other series. The most common combinations of organisms include Staphylococcus aureus and Streptococcus pneumoniae followed by Staphylococcus aureus and Pseudomonas aeruginosa. Candida parapsilosis endocarditis carries a mortality rate of 45%, and each infection with Candida or Pseudomonas endocarditis per se carries a very high mortality rate approaching 85% and 80%, respectively. The combination of P. aeruginosa and C. parapsilosis has never been encountered and there have been no earlier reports of the combination of C. parapsilosis and P. aeruginosa in adult intravenous drug users as a cause of endocarditis. CASE PRESENTATION: We present a 49-year-old man with bivalvular endocarditis with P. aeruginosa and C. parapsilosis. He had a prior bivalvular replacement in 2005 that became infected with the above microorganisms and he was treated with intravenous antibiotics. Because of ongoing intravenous drug use, a second valve replacement was denied. A few days later, the patient presented with septic shock secondary to P. aeruginosa and C. parapsilosis recurrent endocarditis. The infection was cured with a second bivalvular replacement and extended therapy with antibiotics and antifungals. CONCLUSION: This is the first time a patient has presented with P. aeruginosa and C. parapsilosis endocarditis. Relapsing polymicrobial endocarditis can be cured with medical and surgical therapy.