Naturally Occurring Class A β-Lactamases from the Burkholderia cepacia Complex

Chromosomally encoded beta-lactamases from the Burkholderia cepacia complex species (formerly Pseudomonas cepacia) were characterized. Cloning and sequencing identified an Ambler class A beta-lactamase (PenB) from B. cenocepacia. It shares 82% amino acid identity with the PenA beta-lactamases previously identified from B. multivorans 249. Its expression was dependent upon a LysR-type regulatory protein. Its narrow-spectrum hydrolysis activity mostly included penicillins but also included expanded-spectrum cephalosporins and aztreonam at lower levels. In that study, Pen-like beta-lactamases (PenC, PenD, PenE, PenF) that shared 63 to 92% identity with PenB from B. cenocepacia were identified from other Burkholderia species. The corresponding beta-lactamase genes might be used as genetic tools for accurate Burkholderia species identification.