Beta-lactamase enzymes are commonly produced by staphylococci, the Ent
erobacteriaceae, Pseudomonas aeruginosa and certain anaerobic organism
s, such as Bacteroides fragilis. The production of beta lactamases is
an important mechanism through which bacteria become resistant to anti
biotics. The currently marketed beta-lactamase inhibitor combinations
include ampicillin-sulbactam, ticarcillin-clavulanate potassium and, m
ore recently, piperacillin-tazobactam. These extended spectrum antibio
tic combinations share the ability to inhibit methicillin-susceptible
staphylococci, nearly all anaerobic bacteria and many Enterobacteriace
ae. Ticarcillin-clavulanate potassium and piperacillin-tazobactam also
have activity against P. aeruginosa. The combination agents are usefu
l in the treatment of moderate to severe infections, particularly when
a polymicrobial etiology is suspected or documented.