OmpF Downregulation Mediated by Sigma E or OmpR Activation Confers Cefalexin Resistance in Escherichia coli in the Absence of Acquired β-Lactamases
Maryam Alzayn, Punyawee Dulyayangkul, Naphat Satapoomin, Kate J. Heesom, Matthew B. Avison
Abstract
Cefalexin is a widely used first-generation cephalosporin, and resistance in Escherichia coli is caused by extended-spectrum (e.g., CTX-M) and AmpC β-lactamase production and therefore frequently coincides with third-generation cephalosporin resistance. However, we have recently identified large numbers of E. coli isolates from human infections, and from cattle, where cefalexin resistance is not β-lactamase mediated.
Topics & Concepts
Escherichia coliDownregulation and upregulationBiologyPorinBacterial outer membraneMutantMicrobiologyRegulonSigma factorEnterobacteriaceaeCefalexinPlesiomonas shigelloidesLipopolysaccharideMutationCephalosporinGeneGeneticsBacteriaRNA polymeraseAntibioticsImmunologyAntibiotic Resistance in BacteriaBacterial Genetics and BiotechnologyAntibiotics Pharmacokinetics and Efficacy