Amoxicillin resistance in uropathogenic Escherichia coli: extracellular proteomic Insights into transporter and multidrug resistance transporter proteins

Antibiotic resistance in uropathogenic Escherichia coli (UPEC) is a major obstacle to the treatment of urinary tract infections (UTIs). Previous research has focused on antibiotic susceptibility, antibiotic resistance genes, and the underlying intracellular mechanisms therein. This study aims to go beyond existing research by examining the extracellular proteins specifically produced by UPEC in response to amoxicillin (AMX) resistance with the goal of identifying potential therapeutic targets. We selected intrinsically antibiotic-sensitive UPEC strains from previous studies and developed AMX-resistant strains through prolonged AMX exposure. Using nano-based LC-ESI orbitrap mass spectrometry, we analyzed the extracellular proteome of the developed AMX-resistant UPEC and the wild-type control. Proteomics analysis revealed a total of 516 common extracellular proteins in the untreated and AMX-treated developed resistant UPEC strain. While 1,299 extracellular proteins were identified exclusively in the AMX-treated evolved resistant strain, which were categorized into 14 distinct groups based on Gene Ontology (GO) annotation. Among them, the transporter class was the second most abundant class, which included primary active transporters, secondary carrier transporters, and ion channels. Further analysis revealed 57 transporter proteins, including 4 multidrug-resistant transporter proteins, suggesting their potential role in AMX resistance adaptation in UPEC. Such a study can also contribute to creating new drugs or therapies aimed at controlling a wide range of infections, including UTIs, by targeting important identified molecules.