infectious diseases
Enterococcal Infections
Treatment of Enterococcal Infections
Varies by site of infection and susceptibility testing (See also the American Heart Association's2015 Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications.) Enterococci associated with endocarditis are difficult to eradicate unless a combination of certain cell wall–active antibiotics (eg, penicillin,ampicillin,amoxicillin, piperacillin,vancomycin) plus an aminoglycoside (eg,gentamicin,streptomycin) is used to achieve bactericidal activity. However, some cell wall–active antibiotics have limited or no activity against enterococci; they includenafcillin,oxacillin, ticarcillin,ertapenem, most cephalosporins, andaztreonam.E. faeciumare more resistant to penicillin thanE. faecalis. When an aminoglycoside cannot be used, the combination of an aminopenicillin, such asampicillin, plusceftriaxoneis an effective alternative for the treatment ofE. faecalisendocarditis. Imipenem and, to a lesser degree,meropenemare active againstE. faecalis. For complicated skin infections due tovancomycin-susceptible enterococci,daptomycin,linezolid,tedizolid,tigecycline, andomadacyclineare effective treatment options. Piperacillin/tazobactam, imipenem ormeropenem,tigecycline, anderavacyclineare recommended for complicated intra-abdominal infections when enterococci are known or presumed to be involved. Urinary tract infections do not require bactericidal therapy and, if the causative organism is sensitive, are usually treated with a single antibiotic such asampicillinoramoxicillin. In the past several decades, resistance to multiple antimicrobials has increased rapidly, especially amongE. faecium. Resistance to aminoglycosides (eg,gentamicin,streptomycin), particularly withE. faecium, continues to emerge. -resistant enterococci (VRE) may also be resistant to other glycopeptides (eg, teicoplanin), Aminoglycosides , and cell wall–active Beta-lactamase–producing enterococci are occasionally problematic, particularly when large numbers of organisms are present in tissues (eg, in endocarditis vegetation). Resistance may be present clinically even though the organism appears susceptible based on standard testing.Vancomycinor combination beta-lactam/beta-lactamase inhibitor antibiotics (eg,piperacillin/tazobactam,ampicillin/sulbactam) can be used. Enterococci can incorporate exogenously produced folates and thereby reverse the effect oftrimethoprim(TMP) and sulfamethoxazole (SMX); therefore, therapy with these antimicrobials may fail despite apparent in vitro susceptibility (for this reason, TMP/SMX is often left off of susceptibility panels for enterococci). 