Enterococcus: Difference between revisions
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Enterococcus
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* Facultative anaerobic, non-spore-forming, gamma-hemolytic, Gram positive diplococci |
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*Genus of facultative anaerobic, non-spore-forming, [[Hemolysis pattern::α-hemolytic|alpha-]] or [[Hemolysis pattern::γ-hemolytic|gamma-hemolytic]], catalase [[Catalase::negative]], [[Stain::Gram-positive]] [[Shape::coccus|cocci]] |
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*Grows on bile esculin agar |
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*[[PYR test|PYR]] positive |
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*Most are Lancefield group D |
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===Species=== |
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*[[Enterococcus faecalis]] |
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**More common (90-95%) |
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**More commonly genitourinary source |
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**More susceptible to antibiotics |
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*[[Enterococcus faecium]] |
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**Less common (5-10%) |
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**More commonly gastrointestinal source |
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**Less susceptible to antibiotics |
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**Most common VRE |
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*[[Enterococcus avium]] |
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*[[Enterococcus gallinarum]] |
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*[[Enterococcus casseliflavus]] |
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*[[Enterococcus hirae]], a rare zoonotic pathogen from chickens that can cause [[bacteremia]] and [[endocarditis]] |
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===Vancomycin Resistance=== |
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*Vancomycin binds to d-Ala-d-Ala pentapeptids, interfering with cell wall synthesis |
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*'''VanA''': most common. Mutation to d-Ala-d-Lac, leading to high resistance to glycopeptides. |
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*'''VanB''': more common in ''E. faecium'' in Australia |
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*'''VanC''': chromosomal resistance on ''E. gallinarum'' and ''E. casseliflavus'' |
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==Management== |
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* [[Vancomycin]] is usually reliable (except for [[Enterococcus gallinarum]] and [[Enterococcus casseliflavus]]) |
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* [[Ampicillin]] is preferred for susceptible strains |
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* Inherent resistance to [[cephalosporins]] |
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* Resistant to [[ertapenem]], but ampicillin-susceptible strains are often susceptible to [[imipenem]] and (less reliably) to [[meropenem]] |
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===VRE=== |
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*[[Is treated by::Daptomycin]], [[Is treated by::doxycycline]], [[Is treated by::linezolid]], [[Is treated by::tedizolid]], [[Is treated by::oritavancin]], [[Is treated by::quinupristin-dalfopristin]] (for ''E. faecium'') |
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*For VanC isolates, [[ampicillin]] or [[penicillin]] is preferred, and [[daptomycin]] susceptibility is often retained[[CiteRef::jorgensen2003in]] |
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[[Category:Gram-positive cocci]] |
[[Category:Gram-positive cocci]] |
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Latest revision as of 20:36, 23 September 2024
Background
Microbiology
- Genus of facultative anaerobic, non-spore-forming, alpha- or gamma-hemolytic, catalase negative, Gram-positive cocci
- Grows on bile esculin agar
- PYR positive
- Most are Lancefield group D
- Commensal gut flora
- Increasing antibiotic resistance
Species
- Enterococcus faecalis
- More common (90-95%)
- More commonly genitourinary source
- More susceptible to antibiotics
- Enterococcus faecium
- Less common (5-10%)
- More commonly gastrointestinal source
- Less susceptible to antibiotics
- Most common VRE
- Enterococcus avium
- Enterococcus gallinarum
- Enterococcus casseliflavus
- Enterococcus hirae, a rare zoonotic pathogen from chickens that can cause bacteremia and endocarditis
Vancomycin Resistance
- Vancomycin binds to d-Ala-d-Ala pentapeptids, interfering with cell wall synthesis
- VanA: most common. Mutation to d-Ala-d-Lac, leading to high resistance to glycopeptides.
- VanB: more common in E. faecium in Australia
- VanC: chromosomal resistance on E. gallinarum and E. casseliflavus
Management
- Vancomycin is usually reliable (except for Enterococcus gallinarum and Enterococcus casseliflavus)
- Ampicillin is preferred for susceptible strains
- Inherent resistance to cephalosporins
- Resistant to ertapenem, but ampicillin-susceptible strains are often susceptible to imipenem and (less reliably) to meropenem
VRE
- Daptomycin, doxycycline, linezolid, tedizolid, oritavancin, quinupristin-dalfopristin (for E. faecium)
- For VanC isolates, ampicillin or penicillin is preferred, and daptomycin susceptibility is often retained1
References
- ^ James H. Jorgensen, Sharon A. Crawford, Cynthia C. Kelly, Jan E. Patterson. In VitroActivity of Daptomycin against Vancomycin-Resistant Enterococci ofVarious Van Types and Comparison of Susceptibility TestingMethods. Antimicrobial Agents and Chemotherapy. 2003;47(12):3760-3763. doi:10.1128/aac.47.12.3760-3763.2003.
