Pseudomonas aeruginosa: An Unusual Culprit of Left-Sided Native Valve Infective Endocarditis

Endocarditis refers to infection or inflammation of the endocardium, and various pathogens can be involved in infective endocarditis (IE). Endocarditis is usually caused by bacteremia in patients with risk factors, including IV drug abuse, indwelling central venous or urinary catheters, recent dental infections, and implantable cardiac devices. Pseudomonas aeruginosa (P. aeruginosa) is an extremely rare causative organism in IE, predominantly among IV drug users and involving right-sided valves. Left-sided native valve P. aeruginosa IE without established risk factors is uncommon. We present a case of a 68-year-old male with no traditional IE risk factors who presented with intermittent fevers. Blood cultures grew P. aeruginosa, and transesophageal echocardiography revealed posterior mitral valve vegetation. The patient received broad-spectrum IV antibiotics, which were eventually narrowed down to IV cefepime, guided by culture antimicrobial sensitivities. Although the literature describes various risks for P. aeruginosa IE, it can still occur in the absence of traditional predisposing factors. Due to this organism's rapid resistance acquisition and the complication of septic emboli, an expeditious diagnosis and treatment with antibiotics and/or valve surgery are vital to reducing mortality associated with this entity.