Infectious Endocarditis by Pseudomonas aeruginosa in an Immunocompetent Adult

Abstract

In the following case review, we present a 49-year-old male without a history of injection drug (IDU) use nor any known structural heart disease, who developed left-sided pseudomonal infectious endocarditis. The only known risk factors were urinary tract infection (UTI) with secondary bacteremia and prolonged healthcare contact with admission to the intensive care unit.Infectious endocarditis (IE) is the infection of the endocardium. The official diagnosis can only be established after histological and microbiological studies confirm microorganism-colonized vegetations in the heart valves, but a clinical suspicion with high sensitivity and specificity can be approached with modified Duke's criteria. Even though structural heart disease is the major predisposing factor for IE, healthcare-associated IE has risen with the new therapeutic interventions. Transient bacteremia, which might result after various procedures, forms part of the factors causing healthcare-associated IE.Although both, community-acquired and hospital-acquired infections by Pseudomonas aeruginosa have been reported, pure community-acquired infections without previous exposure to the hospital or healthcare environment are extremely rare. Intensive care unit (ICU) patients are at special risk for this microbe. It is considered an important causative agent in ventilator/associated pneumonia, catheter-associated urinary tract infection (UTI), and catheter-associated bloodstream infections. IE by P. aeruginosa remains a rare form of IE. Though 95% of cases are associated with injection drug use (IDU), healthcare contact is becoming more important each day as the primary risk factor. The most common complications include abscesses in the ring and annulus, congestive heart failure (CHF), embolisms, inability to sterilize valves, splenic abscesses, recurrent bacteremia, and neurologic complications. This condition is highly fatal, with a mortality rate of over 73% for patients older than 30 years.Recommended antibiotic treatment for IE caused by P. aeruginosa consists of high-dose tobramycin in combination with antipseudomonal penicillin or high-dose ceftazidime, cefepime, or imipenem.

A Hole in the Heart, a Hole in the Defenses: A Case of Pseudomonas Endocarditis

“…Pseudomonas endocarditis is associated with high mortality and specific risk factors, rarely occurring in immunocompetent patients without these risk factors [ 6 ]. Symptoms are often nonspecific and may include fever, chills, malaise, night sweats, weight loss, skin rash, or, in some cases, signs of heart failure such as shortness of breath, cough, and leg swelling.…”

“…For IE caused by P. aeruginosa , the recommended antibiotic regimen involves high-dose tobramycin (8 mg/kg/day IV or divided doses, given intramuscularly) combined with antipseudomonal penicillin (such as piperacillin, ticarcillin, or azlocillin), or high-dose ceftazidime, cefepime, or imipenem. This treatment should be administered for a duration of six to eight weeks [ 6 ]. However, antibiotic therapy alone has shown limited efficacy, particularly in left-sided pseudomonal IE cases.…”

“…Research suggests that antibiotic concentrations, especially with ceftazidime and tobramycin, often fall below the minimum bactericidal concentration in aortic valve vegetation compared to those in tricuspid valve vegetation. Moreover, the dense microbial population in vegetation may contribute to treatment failure without surgical intervention [ 6 ]. Therefore, timely surgical intervention is essential for improved survival rates in left-sided IE caused by P. aeruginosa .…”