Enterococcus is a topic covered in the Johns Hopkins ABX Guide.

To view the entire topic, please or .

Official website of the Johns Hopkins Antibiotic (ABX), HIV, Diabetes, and Psychiatry Guides, powered by Unbound Medicine. Johns Hopkins Guide App for iOS, iPhone, iPad, and Android included. Explore these free sample topics:

-- The first section of this topic is shown below --

MICROBIOLOGY

  • Enterococci are facultatively anaerobic Gram-positive bacteria in short chains, which grow under extreme conditions, i.e., 6.5% NaCl, pH 9.6, temperature range from 10-45°C, and in the presence of bile salts.
    • Comprise a significant component of normal colonic flora
    • Found in oropharyngeal and vaginal secretions
    • Isolated from soil, water, food
    • They are not as intrinsically virulent as Staphylococcus aureusor Streptococcus pyogenes.
  • Adhere to extracellular matrix proteins and urinary tract epithelia.
    • Produces biofilms.
    • It exploits the opportunity to proliferate once antibiotic-susceptible organisms are eradicated.
  • Antimicrobial resistance attributes[9]
    • Species-specific differences
      • High-level β-lactam resistance is increasing in E. faecium but is uncommon in E. faecalis.
    • Intrinsic resistance to many β-lactams (e.g., cephalosporins) due to inner cell wall penicillin-binding proteins.
    • Resistance to TMP/SMX as enterococci use exogenous folate to overcome the anti-folate synthesis mechanism.
    • Relative impermeability to aminoglycosides (AG), adding a cell-wall agent may allow bactericidal effect at ribosomal target.
      • Ribosomal mutation and decreased aminoglycoside transport confer high-level AG resistance.
      • Some gentamicin-resistant strains may remain susceptible to streptomycin.
  • Vancomycin-resistant enterococci (VRE): occurs E. faecium >>> E. faecalis.[10]
    • Plasmid-mediated VanA and VanB gene complexes confer high-level vancomycin resistance.
    • Increased incidence of vancomycin-resistantE. faecium attributed to the emergence of clonal cluster 17 (CC17) genogroup, CC17 is most common.[17]

-- To view the remaining sections of this topic, please or --

MICROBIOLOGY

  • Enterococci are facultatively anaerobic Gram-positive bacteria in short chains, which grow under extreme conditions, i.e., 6.5% NaCl, pH 9.6, temperature range from 10-45°C, and in the presence of bile salts.
    • Comprise a significant component of normal colonic flora
    • Found in oropharyngeal and vaginal secretions
    • Isolated from soil, water, food
    • They are not as intrinsically virulent as Staphylococcus aureusor Streptococcus pyogenes.
  • Adhere to extracellular matrix proteins and urinary tract epithelia.
    • Produces biofilms.
    • It exploits the opportunity to proliferate once antibiotic-susceptible organisms are eradicated.
  • Antimicrobial resistance attributes[9]
    • Species-specific differences
      • High-level β-lactam resistance is increasing in E. faecium but is uncommon in E. faecalis.
    • Intrinsic resistance to many β-lactams (e.g., cephalosporins) due to inner cell wall penicillin-binding proteins.
    • Resistance to TMP/SMX as enterococci use exogenous folate to overcome the anti-folate synthesis mechanism.
    • Relative impermeability to aminoglycosides (AG), adding a cell-wall agent may allow bactericidal effect at ribosomal target.
      • Ribosomal mutation and decreased aminoglycoside transport confer high-level AG resistance.
      • Some gentamicin-resistant strains may remain susceptible to streptomycin.
  • Vancomycin-resistant enterococci (VRE): occurs E. faecium >>> E. faecalis.[10]
    • Plasmid-mediated VanA and VanB gene complexes confer high-level vancomycin resistance.
    • Increased incidence of vancomycin-resistantE. faecium attributed to the emergence of clonal cluster 17 (CC17) genogroup, CC17 is most common.[17]

There's more to see -- the rest of this topic is available only to subscribers.

Last updated: November 9, 2022