Principles of investigating and treating prosthetic joint, artificial heart valve, pacemaker, and central line infections in normal and immunocompromised patients

Overview

Infection of implanted cardiac devices (prosthetic valves, pacemakers/defibrillators) and central lines requires a distinct approach from other infections - biofilm formation on the device surface protects organisms from both antibiotics and host immune clearance, meaning device removal is frequently necessary alongside prolonged antimicrobial therapy for cure
An increasingly relevant problem given the growing number of patients with implanted cardiac devices and long-term central venous access, particularly in immunocompromised and haemodialysis populations

Biofilm - a structured bacterial community encased in a self-produced extracellular matrix on the device surface - dramatically reduces antibiotic penetration and effectiveness compared with planktonic (free-floating) bacteria, explaining why device-associated infection is often refractory to antibiotics alone regardless of in-vitro organism susceptibility

Blood cultures (repeated, to confirm clearance with treatment), echocardiography (TOE preferred over TTE for suspected prosthetic valve endocarditis given higher sensitivity), and nuclear imaging (PET/labelled white cell scan) for device infection where structural imaging is limited by metal artefact or equivocal
Persistent bacteraemia despite appropriate antibiotics is a red flag for an undrained/device-associated source requiring removal

Device/line removal is frequently required for cure, particularly for prosthetic valve endocarditis with specific high-risk features (heart failure, abscess, resistant organism) and for infected central lines/pacemaker systems - antibiotics alone are often inadequate given the biofilm barrier
Prolonged (often 6+ weeks) targeted intravenous antibiotic therapy accompanies device removal or, when removal is not feasible, is used for extended suppressive treatment

Prosthetic valve endocarditis (higher mortality than native valve endocarditis, more often requiring surgery), central line-associated bloodstream infection (line removal decision-making), cardiac implantable electronic device infection (lead extraction considerations)

Antibiotics alone frequently cannot cure device-associated infection because biofilm on the implant surface protects bacteria from both antimicrobial penetration and host immune clearance - device or line removal should be actively considered as part of the treatment plan, not reserved only for cases that fail a prolonged antibiotic trial first

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