Absence of <i>mgrB</i> Alleviates Negative Growth Effects of Colistin Resistance in <i>Enterobacter cloacae</i>

Abstract

Colistin is an important last-line antibiotic to treat highly resistant Enterobacter infections. Resistance to colistin has emerged among clinical isolates but has been associated with a significant growth defect. Here, we describe a clinical Enterobacter isolate with a deletion of mgrB, a regulator of colistin resistance, leading to high-level resistance in the absence of a growth defect. The identification of a path to resistance unrestrained by growth defects suggests colistin resistance could become more common in Enterobacter.

Keywords

• colistin
• <i>Enterobacter</i>
• CRE