Challenging infective endocarditis: A case of Pseudomonas aeruginosa with emergent antibiotic resistance.

Infective endocarditis (IE) caused by gram-negative microorganisms, particularly Pseudomonas aeruginosa, is a rare but serious condition. This case report details a 76-year-old male who presented with fever and mild urinary symptoms following a recent bacteremia treated with ciprofloxacin. Initial evaluation revealed positive blood cultures for multi-susceptible P. aeruginosa and an abdominal abscess. Despite a favorable initial response to treatment, the patient developed a cerebral infarction due to a septic embolism. Subsequent cultures revealed resistance to piperacillin/tazobactam and ceftazidime, prompting escalation of antibiotic therapy. A transesophageal echocardiogram confirmed infective endocarditis with a vegetative mass on the aortic valve. The patient underwent surgical intervention, with positive cultures from the valve confirming the resistant strain. Following six weeks of targeted antibiotic therapy, he remained asymptomatic for over a year. This case underscores the importance of monitoring for endocarditis in patients with P. aeruginosa bacteremia and highlights the challenges posed by emerging antibiotic resistance.