Enterokokken

Enterokokken, or enterococci, are a genus of Gram-positive, catalase-negative, facultatively anaerobic cocci that occur in pairs or short chains. They are hardy organisms able to tolerate high salt concentrations, bile, and a wide pH range, and may survive in hospital environments for extended periods. They are commonly found as part of the normal intestinal flora of humans and animals, and are also present in water and soil.

The two most clinically important species are Enterococcus faecalis and Enterococcus faecium. Other species include Enterococcus casseliflavus and Enterococcus gallinarum. While they are ordinary gut commensals, they can cause disease when host defenses are weakened or when they spread to normally sterile sites, such as the urinary tract, intra-abdominal space, or bloodstream.

Enterococcal infections include urinary tract infections, bacteremia, endocarditis, intra-abdominal and biliary tract infections, and wound or postoperative infections. They are a common cause of nosocomial infections and can form biofilms on medical devices, contributing to persistence and treatment challenges.

Antibiotic resistance is a major concern. Enterococci possess intrinsic resistance to many cephalosporins and variable susceptibility to penicillins. Treatment often relies on ampicillin or amoxicillin, frequently combined with an aminoglycoside for synergy in serious infections. The emergence of vancomycin-resistant Enterococcus (VRE) limits options and requires agents such as linezolid or daptomycin, guided by susceptibility testing and infection-control measures.

Diagnosis typically relies on culture, with Gram-positive cocci in pairs or short chains, growth in bile esulin and 6.5% NaCl, and species-level identification to guide therapy. Prevention focuses on standard infection-control practices and prudent antibiotic use.