Contribution of BlaA and BlaB β-Lactamases to Antibiotic Susceptibility of Yersinia enterocolitica Biovar 1B

Highly pathogenicYersinia enterocolitica biovar 1B produces two distinct β-lactamases, BlaA and BlaB. Mutants of a representative biovar 1B isolate were constructed and evaluated to determine the extent of limitation of susceptibility to broad-spectrum β-lactam antibiotics by BlaA and BlaB. The results demonstrated that BlaA, a class A enzyme, plays a significant role in limiting susceptibility to penicillins and cephalosporins. The contribution of BlaB, a class C enzyme, was less profound and was limited primarily to cephalosporin susceptibility.