What are the main reasons catheter-associated bacteriuria (CBP) caused by Enterococcus Faecalis can't be fully resolved and cured?

Main Reasons Catheter-Associated Bacteriuria Caused by Enterococcus Faecalis Can't Be Fully Resolved and Cured

The primary reasons catheter-associated bacteriuria (CBP) caused by Enterococcus faecalis is difficult to fully resolve include biofilm formation on catheters, antimicrobial resistance patterns, and catheter retention issues. 1, 2

Biofilm Formation

• E. faecalis has considerable ability to form biofilms on urinary catheters, creating a protective environment that shields bacteria from antimicrobial agents and host immune responses 3
• Biofilm formation allows bacteria to adhere to catheter surfaces and produce an extracellular matrix that significantly reduces antibiotic penetration 3
• All E. faecalis isolates from urinary tract infections have demonstrated biofilm-positive characteristics in laboratory studies 3

Catheter Retention Issues

• Retention of infected catheters significantly reduces cure rates for E. faecalis infections, with studies showing only 38% cure rate when catheters remain in place versus 83% when removed 2
• The Infectious Diseases Society of America recommends removal of infected short-term intravascular catheters for enterococcal infections 1
• For long-term catheters, removal is specifically indicated in cases of insertion site infection, pocket infection, suppurative thrombophlebitis, sepsis, endocarditis, persistent bacteremia, or metastatic infection 1
• When catheter removal is not feasible, persistent bacteremia beyond 72 hours of appropriate antibiotic therapy is common 1

Antimicrobial Resistance

• E. faecalis demonstrates increasing resistance to multiple antibiotics, with 60% of E. faecium and 2% of E. faecalis nosocomial bloodstream infections being resistant to vancomycin 1
• Resistance to newer agents such as linezolid has been reported, further limiting treatment options 1
• Inappropriate antibiotic use for asymptomatic bacteriuria contributes to the development of resistant strains 1
• The universal formation of biofilm along indwelling catheters means antimicrobial therapy may delay but not prevent bacteriuria onset 1

Treatment Challenges

• Monotherapy is often insufficient for catheter-related E. faecalis infections when the catheter remains in place 2
• Combination therapy with a cell wall-active antimicrobial plus an aminoglycoside is more effective than monotherapy when catheters are retained, but the role of combination therapy remains unresolved 1, 2
• Enterococcal bacteremia that persists for more than 4 days has been independently associated with increased mortality 1
• Even with appropriate antimicrobial therapy, recurrence with the same or different species, often with increased antimicrobial resistance, occurs universally when catheters remain in place 1

Complications and Risk Factors

• Diabetes mellitus, prolonged hospital stays (>28 days), and the presence of a urinary catheter are all factors associated with polymicrobial E. faecalis bacteriuria, which is more difficult to treat 4
• Polymicrobial infections appear to be more prevalent than monomicrobial E. faecalis infections (42% vs 32%) and are associated with higher treatment failure rates 4
• The risk of endocarditis as a complication of enterococcal catheter-related bloodstream infection is relatively low (1.5%), but when present significantly complicates treatment 1
• Persistent fever or positive blood cultures after 72 hours of appropriate therapy indicates a need for catheter removal, but this is not always feasible in patients with limited vascular access 1

Prevention and Management Strategies

• Antibiotic lock therapy should be used in addition to systemic therapy if the catheter is retained, but this approach alone is insufficient 1
• Nitrofurazone-impregnated catheters have shown the best antimicrobial durability against E. faecalis biofilms compared to silver-coated or hydrophilic-coated catheters 3
• Limiting the use and duration of urinary catheterization is the most effective preventive strategy 5
• For uncomplicated enterococcal catheter-related infections, a 7-14 day course of therapy is recommended when the short-term catheter is removed or when the long-term catheter is retained with antibiotic lock therapy 1