What is a good antibiotic for treating Enterococcus (enterococcal) infections and Urinary Tract Infections (UTIs)?

From the Guidelines

For enterococcus urinary tract infections (UTIs), a single dose of fosfomycin 3 g PO is recommended as a first-line treatment option, as it has shown efficacy in treating uncomplicated UTIs due to VRE, as per the guidelines and recommendations outlined in the study by 1. The treatment of enterococcus UTIs should be guided by susceptibility testing, as enterococci can have variable resistance patterns. Some key points to consider in the treatment of enterococcus UTIs include:

• Fosfomycin is FDA approved for the treatment of UTI caused by E. faecalis and has in vitro activity against VRE infections, as noted in the study by 1.
• Nitrofurantoin, ampicillin, and amoxicillin are also potential treatment options for uncomplicated UTIs due to VRE, as recommended in the study by 1.
• High-dose ampicillin (18-30 g IV daily) or amoxicillin (500 mg PO/IV every 8 h) may be effective in treating UTIs due to VRE, as suggested in the study by 1.
• Linezolid and daptomycin are also potential treatment options for more complicated UTIs or those caused by resistant strains, as outlined in the study by 1. It is essential to note that the treatment duration should be individualized according to the infection site, source control, underlying comorbidities, and initial response to therapy, as recommended in the study by 1. Patients should complete the full course of antibiotics, even if symptoms improve quickly, and follow up with their healthcare provider if symptoms persist or worsen after 48 hours of treatment. In addition, it is crucial to differentiate colonization from true infection prior to empiric prescription of anti-VRE antimicrobial agents, as emphasized in the study by 1. Overall, the treatment of enterococcus UTIs should be guided by the most recent and highest-quality evidence, and patients should be closely monitored for treatment response and potential adverse effects, as recommended in the study by 1.

From the FDA Drug Label

Linezolid is indicated for the treatment of vancomycin-resistant Enterococcus faecium infections, including cases with concurrent bacteremia [see Clinical Studies (14)]. The cure rates for ITT population with documented vancomycin-resistant enterococcal infection at baseline are presented in Table 15 by source of infection. Urinary tract 12/19 (63) 12/20 (60)

Good antibiotic for enterococcus and UTI:

• Linezolid is effective against vancomycin-resistant Enterococcus faecium infections, including urinary tract infections, with a cure rate of 63% 2.
• The recommended dosage for Linezolid formulations for the treatment of vancomycin-resistant Enterococcus faecium infections is 600 mg intravenously or oral every 12 hours for 14 to 28 days 2.
• It is essential to note that linezolid is not indicated for the treatment of Gram-negative infections, and specific Gram-negative therapy should be initiated immediately if a concomitant Gram-negative pathogen is documented or suspected 2.

From the Research

Antibiotic Options for Enterococcus and UTI

• Ampicillin is generally considered the drug of choice for ampicillin-susceptible enterococcal UTIs, including vancomycin-resistant enterococci (VRE) 3.
• Nitrofurantoin, fosfomycin, and doxycycline have intrinsic activity against enterococci, including VRE, and are possible oral options for VRE cystitis 3, 4.
• Linezolid and daptomycin should be reserved for confirmed or suspected upper and/or bacteremic VRE UTIs among ampicillin-resistant strains 3, 4.
• Quinupristin-dalfopristin and tigecycline may be considered as alternative options, but their use should be evaluated on a case-by-case basis due to concerns of toxicity, resistance, and insufficient supportive data 3, 4.

Treatment Considerations

• Removal of indwelling urinary catheters should be considered in patients with enterococcal UTIs 4.
• Appropriate antibiotic therapy selection should be guided by urine culture and susceptibility results 4.
• Amoxicillin has been associated with a better outcome in patients with enterococcal bacteraemia 5.
• Prior use of antibiotics, immunosuppressive therapy, and mucositis associated with febrile neutropenia are risk factors for ampicillin-resistant enterococcal bacteremia 6.

Resistance and Treatment Challenges

• The rising prevalence of vancomycin-resistant enterococci (VRE) is a concern due to limited treatment options and increased mortality and healthcare costs 3.
• Multidrug resistance in enterococci poses a unique challenge due to their ability to survive in extreme environments, intrinsic antimicrobial resistance, and genomic malleability 7.
• Inefficient antimicrobial therapy is common in enterococcal bacteraemia, highlighting the need for antimicrobial stewardship and careful selection of antibiotic therapy 5.