β-lactamase production in Provotella and in vitro susceptibilities to selected β-lactam antibiotics

This study looked for P-lactamase production in 100 Provotella isolates. MICs were determined for amoxycillin, ticarcillin, amoxycillin+clavulanate, cephalothin, cefuroxime, cefixime, cefpodoxime and cefotaxime using the reference agar dilution method (standard M11 A4, NCCLS). Beta-lactamase activity was detected in 58 of the 100 isolates, 24 of 46 black-pigmented Provotella and 34 of 54 non-pigmented Provotella. All beta-lactamase-negative strains were susceptible to all beta-lactam antibiotics with the exception of cefuroxime and cefixime. Overall, resistance rates of Provotella strains were lower for ticarcillin (8%) and celefotaxime (12%) than for the other cephalosporins. All Provotella isolates were susceptible to amoxyillin and were all inhibited by 2 mg/l or less amoxcillin. (C) 2002 Elsevier Science B.V. and the International Society of Chemotherapy. All rights reserved.