🫀 Enterococcus: The Leading Cause of Endocarditis After TAVI

Published on: July 26, 2025

Author: Team FRCPathPrep

Category: Cardiac Infections, Endocarditis, FRCPath High-Yield

🚨 The Changing Face of Endocarditis

Infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) has become an increasingly recognized complication. While traditionally Staphylococcus aureus and viridans group streptococci dominated the endocarditis landscape, Enterococcus species—particularly Enterococcus faecalis—have now taken centre stage post-TAVI.

🔍 What Is TAVI?

TAVI (or TAVR – Transcatheter Aortic Valve Replacement) is a minimally invasive procedure used to treat severe aortic stenosis in elderly or high-risk surgical patients.

While it avoids open-heart surgery, it does not eliminate the risk of endocarditis — and may actually shift the pathogen profile of post-procedure infections.

🧫 Why Enterococcus?

Recent studies across Europe and the UK reveal that Enterococcus faecalis is now the most common cause of prosthetic valve endocarditis after TAVI.

Risk Factors:

• Elderly patients: Often colonised with enterococci

• Pre-existing GI or GU pathology

• Nosocomial exposure: Enterococci thrive in hospital environments

• Invasive instrumentation: Particularly urinary catheters or colonoscopy near the time of TAVI

🩺 Clinical Clues

Patients may present with:

• Fever, fatigue

• New murmur or cardiac failure

• Positive blood cultures (often delayed diagnosis)

• Vegetations on prosthetic valve (seen on TEE)

👉 E. faecalis may be dismissed early as “gut flora” or contamination — but in a post-TAVI patient, it should ring alarm bells.

🔬 Microbiology & Resistance

Feature	Details
Common species	E. faecalis > E. faecium
Resistance issues	Ampicillin-R, HLAR, VRE possible
Culture	Blood cultures often positive (slow growers)
Imaging	TEE preferred over TTE for prosthetic valves

💊 Treatment Considerations

• Ampicillin + gentamicin (if HLAR-negative)

• Ampicillin + ceftriaxone (synergy without nephrotoxicity)

• Linezolid or daptomycin for resistant strains/VRE

• Prolonged course: 6 weeks, guided by valve type and organism

💡 Remember: HLAR testing is critical in guiding aminoglycoside synergy.

🧠 Exam Tip for FRCPath Candidates

Expect MCQs, SAQs or OSPEs involving:

• Blood culture interpretation in post-TAVI endocarditis

• Appropriate empirical/targeted therapy

• Role of HLAR testing and synergy

• Imaging modality (TEE > TTE for prosthetic valves)

📊 Supporting Data

A multicentre European study (ESC-EORP EURO-ENDO registry) showed:

• Enterococci responsible for ~25–30% of TAVI-IE cases

• Mortality remains high: up to 30–40%

• Often presents subacutely, leading to delayed diagnosis

💡 Key Takeaway:

If you see endocarditis post-TAVI, think Enterococcus first.It’s not just a gut bug — in this setting, it may be the number one culprit.

🧪 FRCPathPrep Resources

🧠 Part 2 Clinical Scenarios on prosthetic valve endocarditis🧫 Part 1 MCQs on enterococcal resistance, synergy testing, and treatment📝 HLAR testing interpretation cases

👉 All available at www.FRCPathPrep.com