Glucose-6-phosphate Reduces Fosfomycin Activity Against Stenotrophomonas maltophilia

Role of the phosphotransferase system in the transport of fosfomycin in Escherichia coli

The inducible inner membrane transporters, UhpT and GlpT are considered to be unique fosfomycin transporters. Glucose-6-phosphate, the substrate for UhpT, enhances fosfomycin activity. Previous work indicates that the fructose phosphotransferase system (PTS) might be involved in fosfomycin transport in the bacterial species, Stenotrophomonas maltophilia. Fosfomycin transport in Escherichia coli has been extensively studied and characterised. The current paper addresses the potential fosfomycin transport activity of the fructose PTS in E. coli. Notably, the deletion of both fructose-specific and general PTS proteins in E. coli increases fosfomycin resistance, which indicates that fructose PTS is involved in fosfomycin transport in E. coli. Further, although inactivation of UhpT, the canonical fosfomycin transporter, in E. coli increases fosfomycin resistance by 2-fold, inactivation of genes encoding the PTS increases it by up to 256-fold. Moreover, intracellular accumulation declines in the absence of both transporters, being mutations in the PTS associated with a larger decline. The results presented in this paper re-open the study of fosfomycin transport and reveal the role of the PTS in the transport of this bactericidal antibiotic in E. coli.

Call for next-generation drugs that remove the uptake barrier to combat antibiotic resistance

Existing antibacterial agents can be categorized into two generations, but bacterial insensitivity towards both of these generations poses a serious public health challenge worldwide. Thus, novel approaches and/or novel antibacterials are urgently needed to maintain a concentration of antibacterials that is lethal to bacteria that are resistant to existing antibiotic treatments. Metabolite(s)-based adjuvants that promote antibiotic uptake and enhance antibiotic efficacy are an effective strategy that is unlikely to develop resistance. Thus, we propose a metabolite(s)-based approach, in which metabolites and antibacterials are combined, as a promising strategy for the development of next-generation agents to combat a variety of antibiotic-resistant pathogens.