persistent enterococcus bateremia and prosthetics

Bacteremia with Enterococcus species has important clinical ramifications, including a 30-day mortality of 20% to 35%, with advanced age, multiple comorbid conditions, or underlying immunocompromised state being important predisposing factors to mortality. Although there is some variability in the definition of what is termed “persistent enterococcal bacteremia,” positive blood cultures after 72 h or more of antimicrobial therapy is generally accepted. The clinical importance of Enterococcus was acknowledged in the 2023 update to the Duke criteria for the diagnosis of infective endocarditis with the addition of E faecalis as a typical pathogen within the major criteria regardless of the primary source and setting of infection. This important change was based on findings that such a designation increased the sensitivity of diagnosing infective endocarditis caused by E faecalis from 70% to 96% without losing specificity. In contrast, Enterococcus faecium, according to one large cohort, accounted for only 9% of enterococcal endocarditis cases. A review of persistent enterococcal bacteremia highlighted the ability of nonintravascular sources to be the source of such a problem.

This patient’s cancer chemotherapy with associated mucositis is a risk factor for a gastrointestinal (GI) source of Enterococcus infection. The 1 week of treatment with ceftriaxone for this patient’s transient viridans streptococcal bloodstream infection predisposes the patient to enterococcal colonization and infection on the basis of the secretion of this antibiotic by the GI tract. In addition to multiplication in the GI tract, this patient has an additional risk factor of prosthetic material, which has the propensity to be a site for biofilm formation. Enterococcus has the ability to enter a persister state when present in biofilm, which results in lower effectiveness of antimicrobial therapy, even when it is appropriately administered. Unfortunately, there are no present pharmaceutical interventions that mitigate the effect of biofilm. Enterococcal osteoarticular infections may be a source of persistent enterococcal bacteremia. The Infectious Diseases Society of America guidelines for the management of prosthetic joint infection list synovial fluid culture as a means of making such a diagnosis. This patient’s persistent enterococcal bacteremia in the absence of intravascular infection (ie, catheter related or endocarditis) makes the joint a possible source.

Although Enterococcus, like Staphylococcus aureus, has the property of endothelial adhesiveness and an enhanced ability to cause endocarditis, it does not characteristically cause epidural abscesses as a manifestation of metastatic infection occurring with prolonged bacteremia.

The patient had a recent episode of community-acquired pneumonia that responded to empiric antibiotic therapy. Even though Streptococcus pneumoniae could potentially be associated with a purulent complication such as empyema (and thereby conform to what is termed “suppurative collection”), Enterococcus is unlikely to be a cause of pulmonary infection.

Like Enterococcus, S aureus and Candida species have the property of endothelial adhesiveness with the risk of causing endocarditis. Unlike Enterococcus, S aureus and Candida bloodstream infection can cause skin lesions as a manifestation of metastatic infection. Enterococcus is not a pathogen that characteristically causes skin infection on either a primary or metastatic basis.123456

A 68-year-old man with colon cancer is admitted with syncope. He received chemotherapy with a 5-fluorouracil-based regimen 3 months previously that caused mucositis, and this was complicated by transient viridans streptococcal bacteremia, for which he received ceftriaxone for 1 week. Two weeks after discharge, he had an episode of community-acquired pneumonia for which he was treated empirically, with clinical resolution over 7 days. The patient’s medical history includes a right hip replacement 1 year ago for severe osteoarthritis. Three days before admission, the patient began having nausea, vomiting, and diarrhea. This progressed to the point that he had a syncopal episode and was taken to the emergency department. His BP was 82/42 mm Hg with a pulse of 134/min and a temperature of 38.2 °C. Physical examination results were notable only for several erythematous well-demarcated plaques with silvery scales over the posterior aspect of his neck and for mild tenderness without erythema over his right hip. The patient’s BP quickly returned to normal with IV fluids, and he started piperacillin-tazobactam and vancomycin. One of two blood cultures drawn at admission subsequently became positive for ampicillin-sensitive Enterococcus faecalis. Blood cultures on the next 4 days remained positive for E faecalis. Transesophageal echocardiography did not show valvular dysfunction or valvular vegetations.

On the basis of this clinical story, which of the following diagnostic tests would be most likely to reveal the basis for this patient’s persistent enterococcal bacteremia?

Footnotes

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  2. Fowler VG, Durack DT, Selton-Suty C, et al. The 2023 Duke-International Society for Cardiovascular Infectious Diseases criteria for infective endocarditis: updating the modified Duke criteria. Clin Infect Dis. 2023;77(4):518-526. PubMed ↩

  3. Osmon DR, Berbari EF, Berendt AR, et al; Infectious Diseases Society of America. Diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2013;56(1):e1-e25. PubMed ↩

  4. Pulido-Perez A, Sanchez-Carrillo C, Bergon-Sendin M, et al. Prevalence and clinical features of secondary skin lesions in septic patients with bloodstream infections. Eur J Clin Microbiol Infect Dis. 2022;41(5):779-786. PubMed ↩

  5. Rogers R, Rice LB. State-of-the-art review: persistent enterococcal bacteremia. Clin Infect Dis. 2024;78(1):e1-e11. PubMed ↩

  6. Tande AJ, Patel R. Prosthetic joint infection. Clin Microbiol Rev. 2014;27(2):302-345. PubMed ↩