ureidopenicillin

Ureidopenicillin is a subclass of penicillin antibiotics characterized by the presence of an ureido group in the side chain. The main representatives are piperacillin, mezlocillin, and azlocillin. Compared with natural and amino penicillins, ureidopenicillins have extended activity against many gram-negative bacteria and, in particular, piperacillin is active against Pseudomonas aeruginosa. They are beta-lactam antibiotics that inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to bacterial lysis. Because of limited oral bioavailability, ureidopenicillins are administered by injection. They are commonly used for severe or hospital-acquired infections and are frequently combined with a beta-lactamase inhibitor, such as tazobactam, to broaden the spectrum and protect against beta-lactamase–producing organisms (for example, piperacillin-tazobactam).

Spectrum and clinical use: Among ureidopenicillins, piperacillin has the broadest activity, covering many gram-negative aerobes and some anaerobes; mezlocillin and azlocillin have similar but variably broader spectra and are less commonly used in some settings. These agents are used for intra-abdominal infections, pneumonia, gynecologic infections, febrile neutropenia, and soft-tissue infections, typically in combination therapy.

Resistance and safety: Resistance can arise through beta-lactamase production, altered penicillin-binding proteins, or efflux mechanisms. As with other penicillins, allergic reactions and other penicillin-associated adverse effects may occur. Care is advised in patients with penicillin allergy, and prolonged use can lead to superinfection or rare nephrotoxic events.