Open AccessAbsence of Mutations in marRAB or soxRS in acrB -Overexpressing Fluoroquinolone-Resistant Clinical and Veterinary Isolates of Escherichia coli
Author(s) -
Mark A. Webber,
Laura J. V. Piddock
Publication year - 2001
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.45.5.1550-1552.2001
Subject(s) - escherichia coli , microbiology and biotechnology , enterobacteriaceae , escherichia coli proteins , mutation , biology , genetics , veterinary medicine , medicine , gene
The amount of acrB, marA, and soxS mRNA was determined in 36 fluoroquinolone-resistant E. coli from humans and animals, 27 of which displayed a multiple-resistance phenotype. acrB mRNA was elevated in 11 of 36 strains. A mutation at codon 45 (Arg-->Cys) in acrR was found in 6 of these 11 strains. Ten of the 36 isolates appeared to overexpress soxS, and five appeared to overexpress marA. A number of mutations were found in the marR and soxR repressor genes, correlating with greater amounts of marA and soxS mRNA, respectively.