Enterococcus: Difference between revisions

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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 or amoxicillin is preferred for susceptible strains
- Piperacillin is effective, as well, but not cloxacillin
Inherent resistance to cephalosporins
Resistant to ertapenem, but ampicillin-susceptible strains are often susceptible to imipenem and (less reliably) to meropenem12

VRE

Daptomycin, doxycycline, linezolid, tedizolid, oritavancin, quinupristin-dalfopristin (for E. faecium)
For VanC isolates, ampicillin or penicillin is preferred, and daptomycin susceptibility is often retained3

References

^ Carl-Johan Fraenkel, Måns Ullberg, Sverker Bernander, Evalena Ericson, Peter Larsson, Johan Rydberg, Eva Törnqvist, Åsa Melhus. In vitro activities of three carbapenems against recent bacterial isolates from severely ill patients at Swedish hospitals. Scandinavian Journal of Infectious Diseases. 2006;38(10):853-859. doi:10.1080/00365540600684371.
^ 10.1093/jac/39.2.149
^ 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.

@@ Line 1: / Line 1: @@
-== Background ==
+==Background==
-=== Microbiology ===
+===Microbiology===
-* Facultative anaerobic, non-spore-forming, alpha- or gamma-hemolytic, [[Has Gram stain::Gram-positive]] [[Cellular shape::cocci]]
-* Grows on bile esculin agar
-* Most are Lancefield group D
-* Commensal gut flora
-* Increasing antibiotic resistance
+*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]]
-=== Species ===
+*Grows on bile esculin agar
-* ''E. faecalis''
+*[[PYR test|PYR]] positive
-** More common (90-95%)
+*Most are Lancefield group D
-** More commonly genitourinary source
+*Commensal gut flora
-** More susceptible to antibiotics
+*Increasing antibiotic resistance
-* ''E. faecium''
-** Less common (5-10%)
-** More commonly gastrointestinal source
-** Less susceptible to antibiotics
-** Most common VRE
-* ''E. gallinarum''
-* ''E. casseliflavus''
-=== Vacomycin Resistance ===
+===Species===
-* 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''
+*[[Enterococcus faecalis]]
-== Management ==
+**More common (90-95%)
-=== VRE ===
+**More commonly genitourinary source
-* [[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'')
+**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===
-{{DISPLAYTITLE:''Enterococcus'' species}}
+*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]] or [[amoxicillin]] is preferred for susceptible strains
+** [[Piperacillin]] is effective, as well, but not [[cloxacillin]]
+* Inherent resistance to [[cephalosporins]]
+* Resistant to [[ertapenem]], but ampicillin-susceptible strains are often susceptible to [[imipenem]] and (less reliably) to [[meropenem]][[CiteRef::fraenkel2006in]][[CiteRef::10.1093/jac/39.2.149]]
+===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[[CiteRef::jorgensen2003in]]
+{{DISPLAYTITLE:''Enterococcus''}}
 [[Category:Gram-positive cocci]]