ROBA-INDUCED MULTIPLE ANTIBIOTIC-RESISTANCE LARGELY DEPENDS ON THE ACTIVATION OF THE ACRAB EFFLUX

RobA is a member of the XylS/AraC subfamily of DNA binding proteins, a nd when overexpressed, it induces multiple antibiotic resistance in Es cherichia coli, In this study, we introduced a multicopy robA plasmid (pMEP1) and its derivative into OmpF mutants and an AcrAB-deficient mu tant, We found that a decrease in susceptibility to multiple antibioti cs in these OmpF mutants when pMEP1 was introduced did not depend on O mpF porin expression, Interestingly, a Delta ompF mutant (TK007) becam e more sensitive when pMEP1 was introduced, Moreover no effect of RobA on the induction of multiple antibiotic resistance in an acrA1(-) mut ant was observed, Therefore, we conclude that the multiple antibiotic resistance induced by the overexpression of RobA largely depends on th e activation of the AcrAB efflux, as well as the activation of micF.