Interaction of cefotetan and the metallo-β-lactamases produced in Aeromonas spp. and in vitro activity

Aeromonas spp, are increasingly being recognized as human pathogens. The presence of metallo-β-lactamases in these organisms represents a potential problem in antimicrobial therapy. Mechanism-based inactivators of β-lactamases are used to overcome the resistance of clinical pathogens to β-lactam antibiotics, but no clinical useful inhibitors of the metallo-β-lactamases are presently known. Studying the interaction between cefotetan and Aeromonas spp. producing metallo-β-lactamase activity, we observed that cefotetan behaved as a transient inactivator for both the crude extracts of Aeromonas strains and the purified enzymes from Aeromonas hydrophila AE036 and Aeromonas schubertii MNSA20. The direct hydrolysis of cefotetan showed that it was a poor substrate for both purified enzymes. In view of the minimum inhibitory concentrations, cefotetan shows to be a useful antimicrobial agent against Aeromonas spp. Copyright (C) 2000 S. Karger AG. Basel.