enterokocker

Enterokocker, or enterococci, are a group of Gram-positive cocci that commonly inhabit the gastrointestinal tracts of humans and animals. The two most clinically important species are Enterococcus faecalis and Enterococcus faecium. While usually harmless as part of the normal flora, enterococci can cause opportunistic infections, particularly in hospitalized patients, and are notable for their ability to acquire resistance to multiple antibiotics.

In laboratory terms, enterococci are non-spore-forming, facultative anaerobes that occur in pairs or short chains. They are catalase negative and can grow in high salt concentrations (such as 6.5% NaCl) and in the presence of bile, where they hydrolyze esculin. They may show gamma, alpha, or sometimes beta hemolysis on blood agar. Identification often relies on a combination of biochemical tests, including PYR positivity, along with antibiotic susceptibility patterns. Enterococci are intrinsically resistant to many cephalosporins and often demonstrate variable susceptibility to penicillins and aminoglycosides.

Clinically, enterococci are a common cause of urinary tract infections, bacteremia, intra-abdominal and pelvic infections, and endocarditis. They are particularly significant in healthcare-associated infections and in patients with indwelling medical devices or prior antimicrobial exposure. Vancomycin-resistant Enterococcus (VRE) strains pose treatment challenges, especially in Enterococcus faecium.

Treatment choices depend on species and susceptibility. Options may include ampicillin or vancomycin for susceptible strains, often with gentamicin for synergy. Linezolid or daptomycin may be used for resistant infections. Effective management also relies on infection control measures and antibiotic stewardship to limit spread and resistance.