View source for Enterococcus


==Background==

===Microbiology===

*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]]
*Grows on bile esculin agar
*[[PYR test|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 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===

*[[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'')
*For VanC isolates, [[ampicillin]] or [[penicillin]] is preferred, and [[daptomycin]] susceptibility is often retained<ref>Jorgensen JH, Crawford SA, Kelly CC, Patterson JE. In vitro activity of daptomycin against vancomycin-resistant enterococci of various Van types and comparison of susceptibility testing methods. ''Antimicrob Agents Chemother''. 2003 Dec;47(12):3760-3. doi: [https://doi.org/10.1128%2FAAC.47.12.3760-3763.2003 10.1128/AAC.47.12.3760-3763.2003]. PMID: [https://pubmed.ncbi.nlm.nih.gov/14638478 14638478]; PMCID: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC296189/ PMC296189].</ref>

{{DISPLAYTITLE:''Enterococcus''}}
[[Category:Gram-positive cocci]]