The development of an analysis protocol based on flow cytometry for rapid detection of uropathogenic E. coli in artificially contaminated urine samples

Inappropriate empiric treatment for urinary tract infections (UTI) has led to a significant increase in the prevalence of resistant pathogens and is associated with a rise in hospital mortality. Novel diagnostic platforms, including flow cytometry (FC) devices, are needed for timely microbial identification and rapid antimicrobial susceptibility testing (AST). The aim of the present study was the design and optimization of a rapid assay, based on FC, for direct detection of resistant E. coli directly in artificially urine samples. A total of thirty Escherichia coli strains, isolated from UTI, grown in artificial urine were investigated and four antibiotics were tested. FC analysis investigated the bacterial viability based on the assessment of increased membrane permeability for propidium iodide. The results obtained by FC tests were compared with standard AST cultivation methods (VITEK-2 automated system). The developed FC based assay was demonstrated to detect antibiotic resistant E. coli isolates, in less than four hours analysis time, directly in artificial urine samples. The developed analysis method could improve the accuracy of emergency antimicrobial therapy in UTIs.