Pseudomonas mendocina native valve infective endocarditis: a case report

Gram-negative microorganisms are uncommon pathogens responsible for infective endocarditis. Pseudomonas mendocina, a Gram-negative water-borne and soil-borne bacterium, was first reported to cause human infection in 1992. Since then, it has rarely been reported as a human pathogen in the literature. We describe the first case of native valve infective endocarditis due to P. mendocina in the USA.

A 57-year-old white man presented with bilateral large leg ulcers, fever, and marked leukocytosis. His past medical history included gout and chronic alcohol use. P. mendocina was isolated from his blood cultures. A comprehensive review of P. mendocina infection in the literature was performed. A total of eight cases of P. mendocina infection were reported in the literature. More than two-thirds of the cases of P. mendocina septicemia were associated with native valve infective endocarditis. Thus, an echocardiogram was performed and demonstrated mitral valve endocarditis with mild mitral insufficiency. His leg wounds were debrided and were probably the source of P. mendocina bacteremia. Unlike Pseudomonas aeruginosa, P. mendocina is susceptible to third-generation cephalosporins. Our patient received a 6-week course of antimicrobial therapy with a favorable clinical outcome.

Our reported case and literature review illuminates a rare bacterial cause of infective endocarditis secondary to P. mendocina pathogen. Native cardiac valves were affected in all reported cases of infective endocarditis, and a majority of affected heart valves were left-sided. The antibiotics active against P. mendocina are different from those that are active against P. aeruginosa, and they notably include third-generation cephalosporins. The outcome of all reported cases of P. mendocina was favorable and no mortality was described.