Which drug provides adequate empiric coverage against both Escherichia coli and Bacteroides fragilis?

Piperacillin/tazobactam is a combination antibiotic that is particularly effective against a wide range of bacteria, including both Escherichia coli and Bacteroides fragilis. Piperacillin is a broad-spectrum penicillin that inhibits bacterial cell wall synthesis, making it effective against various gram-positive and gram-negative organisms, while tazobactam serves as a beta-lactamase inhibitor. This combination significantly enhances the drug's effectiveness by protecting piperacillin from degradation by beta-lactamase enzymes produced by certain bacteria, particularly those producing the enzymes that make them resistant to penicillins.

Escherichia coli is a common enteric gram-negative organism that can commonly be treated with piperacillin/tazobactam, and Bacteroides fragilis is an anaerobic gram-negative bacillus often found in abdominal infections. The combination of piperacillin and tazobactam ensures that the coverage extends not only to aerobic gram-negative organisms like E. coli, but also to anaerobic bacteria such as B. fragilis.

Other options, such as cefepime, aztreonam, and ceftaroline, have specific limitations. Cefepime is effective against Pseud