Enterococcus
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.
- Species-specific differences
- 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]
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Last updated: November 9, 2022
Citation
Spacek, Lisa A. "Enterococcus." Johns Hopkins ABX Guide, The Johns Hopkins University, 2022. Pediatrics Central, peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540203/all/Enterococcus.
Spacek LA. Enterococcus. Johns Hopkins ABX Guide. The Johns Hopkins University; 2022. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540203/all/Enterococcus. Accessed September 7, 2024.
Spacek, L. A. (2022). Enterococcus. In Johns Hopkins ABX Guide. The Johns Hopkins University. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540203/all/Enterococcus
Spacek LA. Enterococcus [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2022. [cited 2024 September 07]. Available from: https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540203/all/Enterococcus.
* Article titles in AMA citation format should be in sentence-case
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T1 - Enterococcus
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BT - Johns Hopkins ABX Guide
UR - https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540203/all/Enterococcus
PB - The Johns Hopkins University
DB - Pediatrics Central
DP - Unbound Medicine
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