Single-Dose Oral Amoxicillin or Linezolid for Prophylaxis of Experimental Endocarditis Due to Vancomycin-Susceptible and Vancomycin-Resistant Enterococcus faecalis
- 1 May 2007
- journal article
- Published by American Society for Microbiology in Antimicrobial Agents and Chemotherapy
- Vol. 51 (5), 1661-1665
- https://doi.org/10.1128/aac.00744-06
Abstract
Endocarditis prophylaxis following genitourinary or gastrointestinal procedures targets Enterococcus faecalis . Prophylaxis recommendations advocate oral amoxicillin (2 g in the United States and 3 g in the United Kingdom) in moderate-risk patients and intravenous amoxicillin (2 g) or vancomycin (1 g) plus gentamicin in high-risk patients. While ampicillin-resistant (or amoxicillin-resistant) E. faecalis is still rare, there is a concern that these regimens might fail against vancomycin-resistant and/or aminoglycoside-resistant isolates. The present study tested oral linezolid as an alternative. Rats with catheter-induced aortic vegetations were given prophylaxis simulating human pharmacokinetics of oral amoxicillin (2- to 3-g single dose), oral linezolid (600 mg, single or multiple oral doses every 12 h), or intravenous vancomycin (1-g single dose). Rats were then inoculated with the minimum inoculum infecting 90% of the animals (90% infective dose [ID 90 ]) or with 10 times the ID 90 of the vancomycin-susceptible E. faecalis strain JH2-2 or the vancomycin-resistant (VanA phenotype) E. faecalis strain UCN41. Amoxicillin was also tested with two additional vancomycin-susceptible E. faecalis strains, 309 and 1209. Animals were sacrificed 3 days later. All the tested bacteria were susceptible to amoxicillin and gentamicin. Single-dose amoxicillin provided 100% protection against all four isolates at both the ID 90 and 10 times the ID 90 . In contrast, linezolid required up to four consecutive doses to provide full protection against the vancomycin-resistant isolate. Vancomycin protected only against the vancomycin-susceptible strain. The high efficacy of single-dose oral amoxicillin suggests that this regimen could be used for prophylaxis in both moderate-risk and high-risk patients without additional aminoglycosides. Linezolid appears to be less reliable, at least against the vancomycin-resistant strain.This publication has 42 references indexed in Scilit:
- Linezolid in Prophylaxis against Experimental Aortic Valve Endocarditis Due to Streptococcus oralis or Enterococcus faecalisAntimicrobial Agents and Chemotherapy, 2006
- Enterococcal prosthetic valve infective endocarditis: report of 45 episodes from the International Collaboration on Endocarditis-merged databaseEuropean Journal of Clinical Microbiology & Infectious Diseases, 2005
- Molecular and clinical epidemiology of vancomycin-resistant Enterococcus faecalisJournal of Antimicrobial Chemotherapy, 2004
- Simulation of Human Gentamicin Pharmacokinetics in an Experimental Enterococcus faecalis Endocarditis ModelAntimicrobial Agents and Chemotherapy, 2003
- Clinical Pharmacodynamics of Linezolid in Seriously Ill Patients Treated in a Compassionate Use ProgrammeClinical Pharmacokinetics, 2003
- Aminoglycoside Resistance in EnterococciClinical Infectious Diseases, 2000
- Role of Amoxicillin Serum Levels for Successful Prophylaxis of Experimental Endocarditis Due to Tolerant StreptococciThe Journal of Infectious Diseases, 1994
- Oral Amoxicillin as Prophylaxis for Endocarditis: What Is the Optimal Dose?Clinical Infectious Diseases, 1994
- Comparison of Single Doses of Amoxicillin or of Amoxicillin-Gentamicin for the Prevention of Endocarditis Caused by Streptococcus faecalis and by Viridans StreptococciThe Journal of Infectious Diseases, 1985
- High-dose oral amoxycillin for preventing endocarditis.BMJ, 1980