Direct Detection and Identification of Bacterial Pathogens from Urine with Optimized Specimen Processing and Enhanced...

Area of Science:

• Clinical Microbiology
• Analytical Chemistry
• Medical Diagnostics

Background:

• Urinary tract infections (UTIs) require rapid and accurate pathogen detection for effective treatment.
• Current diagnostic methods can be time-consuming, delaying targeted therapy.
• Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers potential for rapid microbial identification.

Purpose of the Study:

• To optimize specimen processing for enhanced limit of detection (LOD) using MALDI-TOF MS for direct urine analysis.
• To evaluate the diagnostic performance of MALDI-TOF MS, alone and combined with urine analysis (UA), for bacterial pathogen detection in urine samples.

Main Methods:

• Optimized urine processing parameters including sample volume, formic acid/acetonitrile concentration, and supernatant volume for MALDI-TOF MS.
• Evaluated the limit of detection (LOD) of the optimized MALDI-TOF MS method.
• Compared the diagnostic accuracy (sensitivity, specificity, PPV, NPV) of MALDI-TOF MS and UA-MALDI-TOF MS against a reference standard (urine culture and 16S rRNA gene sequencing) using 1,167 clinical urine specimens.

Main Results:

• Optimized processing achieved an LOD of 1.0 × 10^5 CFU/ml.
• The combination of UA and MALDI-TOF MS demonstrated higher sensitivity (93.4%) and specificity (96.3%) compared to MALDI-TOF MS alone (86.6% and 91.5%, respectively).
• UA-MALDI-TOF MS showed significantly improved positive predictive value (96.4%) over MALDI-TOF MS alone (81.5%).
• Performance was consistent across three hospital centers, though specificity and NPV were higher in males than females.

Conclusions:

• Optimized specimen processing significantly improves the analytical sensitivity of MALDI-TOF MS for urine samples.
• The combination of urine analysis and MALDI-TOF MS provides a rapid, accurate, and sensitive method for direct bacterial pathogen detection and identification in urine.
• This approach holds promise for improving the diagnosis and management of urinary tract infections.