[Moxalactam: an inactivator of beta-lactamases].

At present, Moxalactam is the beta-lactam antibiotic which shows the greatest resistance to beta-lactamases. Moxalactam has little, if any, interactions with penicillinases, as is also the case of cefoxitin, cefuroxime and cefotaxime. Resistance of Moxalactam to cephalosporinases, however, appears to be related to the unique property of inactivating them. This implies: a specific process which involves the active site of the enzymes; a progressive, or time-dependent, process, which progressively abolishes beta-lactamase activity. This process was observed with most of the tested cephalosporinases. Thus, Moxalactam is the first beta-lactam antibiotic which inactivates beta-lactamases. This is probably why Moxalactam is so resistant to the action of beta-lactamases.