Microbiology in pictures

Enterococcus faecalis

Enterococcus faecalis on blood agar plate

Enterococcus faecalis on Columbia agar with 5% sheep blood. Fig. A, B, C: mixture of colonies of E. faecalis and Streptococcus pyogenes (from a patient with prosthetic joint infection). Colonies are without hemolysis (gamma-hemolysis) or, in some strains, surrounded by a zone of alpha-hemolysis.

Enterococcus faecalis formerly classified as part of the Group D Streptococcus system is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. Like other species in the genus Enterococcus, E. faecalis can cause life-threatening infections in humans, especially in the nosocomial (hospital) environment, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity.


E. faecalis can cause endocarditis and bacteremia, urinary tract infections (UTI), meningitis, and other infections in humans. In the United States, E. faecalis is associated with nosocomial infections including catheter-associated UTI, central line-associated bloodstream infection, and surgical site infections. Several virulence factors are thought to contribute to E. faecalis infections. A plasmid-encoded hemolysin, called the cytolysin, is important for pathogenesis in animal models of infection, and the cytolysin in combination with high-level gentamicin resistance is associated with a five-fold increase in risk of death in human bacteremia patients.

Abbreviated from Wikipedia.

description image
GRAM-POSITIVE COCCI
NONMOTILE
NONSPOREFORMING
CATALASE: NEGATIVE
OXIDASE: NEGATIVE
FACULTATIVELY   ANAEROBIC

BASIC TESTS
FOR IDENTIFICATION

beta-hemolysis:-
catalase test:-
PYR test:+
Esculin hydrolysis:+
Bile tolerance:
(growth on bile esculin agar)
+
L-tyrosine decarboxylase:+
NaCl tolerance (6.5%):+

ANTIBIOTIC
TREATMENT

Should be always guided by
in vitro susceptibility
tests!!

Selection of appropriate antibiotics depends on diagnosis!!

IF SUSCEPTIBLE:

Ampicillin(AMP)
Amoxicillin(AMX)
AMP + Gentamicin(GEN)
AMX + GEN
Penicillin G + GEN

ALTERNATIVES:

Nitrofurantoin
Norfloxacin
Ofloxacin
Ciprofloxacin
Imipenem
Vancomycin
Teicoplanin
------------------------
Linezolid
Daptomycin
list of anntibiotics
Gram-positive ovoid cocci drawing

COLONY MORPHOLOGY

enterococcus faecalis enterococcus faecalis enterococcus faecalis enterococcus faecalis
enterococcus faecalis enterococcus faecalis enterococcus faecalis enterococcus faecalis
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Enterococcus sp.

Enterococcus faecalis

Vancomycin-resistant Enterococcus (VRE)

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Pathophysiology

Epidemiology

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