# Comparative Evaluation of Conventional Methods and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for Uropathogen Identification in Catheter-Associated Urinary Tract Infections in ICU Patients

## TL;DR

This study compares traditional methods and MALDI-TOF MS for identifying urinary tract infection pathogens in ICU patients, finding MALDI-TOF MS to be faster and more accurate.

## Contribution

The study provides a direct comparison of MALDI-TOF MS and conventional methods for uropathogen identification in ICU CAUTI cases.

## Key findings

- MALDI-TOF MS showed strong agreement with conventional methods (Cohen’s Kappa 0.787).
- Common pathogens included Candida species, Enterococcus, and Escherichia coli.
- High resistance to fluoroquinolones and cephalosporins was observed.

## Abstract

Background

Catheter-associated urinary tract infections (CAUTIs) are a significant concern in ICU patients, often leading to complications such as bloodstream infections, urosepsis, prolonged hospitalization, and increased mortality, particularly due to delayed diagnosis and rising antibiotic resistance. For therapy to be effective, the causing pathogens must be identified quickly and accurately. This study compares conventional microbiological methods with Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for identifying urinary isolates in CAUTI cases and examines their antibiotic susceptibility patterns.

Methods

Over one year, we analyzed 780 catheterized urine samples from ICU patients at a tertiary care hospital. All samples were processed using standard culture techniques and MALDI-TOF MS for pathogen identification. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Descriptive statistics were used for data summarization, and Chi-square test assessed associations between risk factors and CAUTI occurrence, with agreement between MALDI-TOF MS and conventional identification methods evaluated by Cohen’s Kappa analysis. The Chi-square test's statistical significance was set at p < 0.05.

Results

Out of 780 samples, 156 (20%) showed significant bacterial or fungal growth. The most common pathogens were Candida species (56.4%), Enterococcus (17.9%), and Escherichia coli (12.2%). MALDI-TOF MS demonstrated good accuracy, with misclassifications in 12 isolates (7.7%) mainly involving misidentification in Enterococcus and Candida. Despite these discrepancies, a strong agreement was observed between the two methods, with a Cohen’s Kappa value of 0.787. High resistance was observed against fluoroquinolones and cephalosporins, while fosfomycin and linezolid remained effective against Enterococcus spp.

Conclusion

MALDI-TOF MS enhances the speed and accuracy of pathogen identification, making it a valuable tool for managing CAUTI cases. The increasing antibiotic resistance observed in this study highlights the urgent need for targeted treatment strategies and stricter infection control measures in ICU settings.