Role of OmpF and OmpC in Kanamycin-induced Resistance to Kanamycin and Transient Cross-Resistance to Ampicillin in Escherichia coli K12

Abstract

The expression of porins may have a role in the induced resistance and transiently induced cross-resistance that E. coli B23 exhibits following pre-treatment with sublethal levels of kanamycin. This study aimed to ascertain whether OmpF plays a role in protecting cells from the full effects of subsequent inhibitory levels of kanamycin treatment and lethal levels of ampicillin treatment. Minimal inhibitory concentration assays were used to determine subinhibitory levels of kanamycin, which were then used in a pre-treatment of wildtype (C149) E. coli K12 as well as OmpF- (C150), OmpC – (C157), and OmpC- OmpF- (C160) E. coli K12 mutants. The sublethal treatment was followed by treatment with inhibitory levels of either kanamycin or ampicillin. By comparing pre-treated cultures with untreated cultures and by comparing the resistance in the mutant strains with wildtype K12 we were able to analyse potential effects OmpF and OmpC have on induced resistance and cross-resistance. Results indicated that OmpF and OmpC proteins were not the sole contributors to the induced resistance phenomenon and may only play minor roles.