Stabilita di cefuroxime alle β-lattamasi: Implicazioni per il suo impiego terapeutico

Bacteria continuously evolve their resistance mechanisms to antibiotics, either in community or in the hospital setting. Production of β-lactamases is one of the oldest way to overcome antimicrobial agents activity, since it was first described in 1944 immediately after the penicillin discovery. Beta- lactamases are enzymes hydrolysing the β-lactam nucleus of beta-lactam antibiotics by using two strategies: a nucleophilic attack of a serine residue or activating a water molecule via a Zn++. Cefuroxime is a injectable cephalosporin which can be also orally administered as a pro-drug named cefuroxime axetil. Cefuroxime has been classified as a second generation cephalosporin, even though the strict subgrouping of cephalosporins into classes is critically discussed by the Authors. Cefuroxime was the first beta-lactam with a higher stability to beta- lactamase hydrolysis due to its methoxy-imino side chain in position 7 of the cephem nucleus. Many of the clinically significant bacterial species producing betalactamases such as Haemophilus, Moraxella, Staphylococci and most Enterobacteriaceae then remain susceptible to cefuroxime. The more evoluted enzymes such as carbapenemases, extended-spectrum beta-lactamases or over-expressed cephalosporinases hydrolyse nearly all the beta-lactams antibiotics including cefuroxime. The available literature on the bacterial susceptibility to cefuroxime in Italy and use of cefuroxime in clinical settings where beta-lactamase producing bacteria could be involved has been analysed in the review. In conclusion, cefuroxime still represents a valid therapeutic option even in presence of most of the beta-lactamase producing bacteria.