Direct MALDI-TOF MS identification from positive blood culture bottles: a time-saving approach to reduce diagnostic...

Bloodstream infections are a leading cause of mortality worldwide, necessitating prompt identification and treatment to improve patient outcomes. Conventional methods are time-consuming, often delaying appropriate antimicrobial therapy. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a revolutionary tool for rapid microbial identification. This study aimed to evaluate the utility of direct microbial identification from positive blood cultures using MALDI-TOF MS in reducing diagnostic delays and improving pathogen detection for effective clinical management.

This prospective study analyzed 416 monomicrobial positive blood cultures obtained between October 2022 and October 2024 from a tertiary care teaching hospital in North India. After Gram staining and initial processing, direct microbial identification was performed using MALDI-TOF MS. Conventional subculture-based methods were employed as the gold standard for comparison.

Of the 416 isolates, 89% were correctly identified at the species level using the direct method. Among 204 Gram positive cocci, 91.6% were correctly identified, with species-specific rates of 100% for Staphylococcus aureus and Staphylococcus ureilyticus. Out of 160 Gram negative bacilli, 88.1% were accurately identified, with Acinetobacter baumannii showing 97.5% accuracy. Candida species showed a correct identification rate of 80.8%, with 100% identification for Candida albicans and Candida krusei.

Direct microbial identification using MALDI-TOF MS is a rapid, cost-effective alternative to conventional methods, enabling faster pathogen detection and supporting antimicrobial stewardship.