Background: Antibiotic resistance complicates management of urinary tract infections (UTIs), particularly those caused by Pseudomonas aeruginosa, which is frequently resistant to first line therapies. Because culture and sensitivity (C&S) testing requires 48–72 hours, clinicians often rely on empiric therapy that may fail against multidrug resistant organisms. This proof of concept study evaluated whether label free optical spectroscopy can rapidly distinguish P. aeruginosa from other common uropathogens in artificial urine.
Methods: Absorbance and fluorescence spectroscopy were assessed for differentiating Klebsiella pneumoniae, P. aeruginosa, and Escherichia coli grown in artificial urine and tested under varying pH buffer conditions. Samples were excited at 370 nm on a BioTek Synergy H4 spectrophotometer, and emission spectra were examined for organism specific features. Each condition included technical duplicates across multiple independent experiments at pathological (105 – 106 CFU/mL) bacterial densities. Endpoint spectra were collected after mixing inoculated urine with buffers, and discrimination was based on visual peak differences and signal-to-noise ratios above 3.
Results: Absorbance spectra showed no organism specific features. In contrast, fluorescence spectra revealed a distinct 460–470 nm emission in bicarbonate (pH 6) and TRIS (pH 8) buffers that consistently identified P. aeruginosa and was absent in K. pneumoniae and E. coli.
Conclusion: Fluorescence spectroscopy in artificial urine successfully differentiated P. aeruginosa from other uropathogens, supporting feasibility for a rapid, low cost, and label free screening method to complement C&S testing. Limitations include use of artificial urine, small sample size, and absence of rigorous quantitative analysis. Future work will assess performance in clinical urine and expand organism testing.
Methods: Absorbance and fluorescence spectroscopy were assessed for differentiating Klebsiella pneumoniae, P. aeruginosa, and Escherichia coli grown in artificial urine and tested under varying pH buffer conditions. Samples were excited at 370 nm on a BioTek Synergy H4 spectrophotometer, and emission spectra were examined for organism specific features. Each condition included technical duplicates across multiple independent experiments at pathological (105 – 106 CFU/mL) bacterial densities. Endpoint spectra were collected after mixing inoculated urine with buffers, and discrimination was based on visual peak differences and signal-to-noise ratios above 3.
Results: Absorbance spectra showed no organism specific features. In contrast, fluorescence spectra revealed a distinct 460–470 nm emission in bicarbonate (pH 6) and TRIS (pH 8) buffers that consistently identified P. aeruginosa and was absent in K. pneumoniae and E. coli.
Conclusion: Fluorescence spectroscopy in artificial urine successfully differentiated P. aeruginosa from other uropathogens, supporting feasibility for a rapid, low cost, and label free screening method to complement C&S testing. Limitations include use of artificial urine, small sample size, and absence of rigorous quantitative analysis. Future work will assess performance in clinical urine and expand organism testing.