CARB-9, a Carbenicillinase Encoded in the VCR Region of <i>Vibrio cholerae</i> Non-O1, Non-O139 Belongs to a Family of Cassette-Encoded β-Lactamases

Abstract

The gene bla(CARB-9) was located in the Vibrio cholerae super-integron, but in a different location relative to bla(CARB-7). CARB-9 (pI 5.2) conferred beta-lactam MICs four to eight times lower than those conferred by CARB-7, differing at Ambler's positions V97I, L124F, and T228K. Comparison of the genetic environments of all reported bla(CARB) genes indicated that the CARB enzymes constitute a family of cassette-encoded beta-lactamases.