Poblational and biochemical-structural analyses on CTX-M @b-lactamases harboring the D240G mutation reveal that E. coli populations with decreased susceptibility to ceftazidime preexist under a multifactorial resistance profile

摘要

Purpose: CTX-M β-lactamases possess high catalytic efficiency towards cefotaxime (CTX) but spare ceftazidime (CAZ). Variants harboring the replacement of D240 by a glycine (D240G substitution) have been associated with a decreased susceptibility to CAZ. We analyzed the influence of D240G, and spontaneous porin deficient subpopulations in the five CTX-M sub families in relation to final MICs.