Rapid Bacterial Identification from Positive Blood Cultures by MALDI-TOF MS Following Short-Term Incubation on Solid Media.

ABSTRACT

This study aimed to assess the performance of the MALDI-TOF MS short incubation method for bacterial identification at short-term incubation times to improve the reporting of blood cultures. MALDI-TOF MS analysis was conducted at intervals of 2, 4, and 6 hours during the development of microbial biomass on solid media until successful identification was achieved, with a final assessment at 24 hours for conventional identification. Species-level identification rates at the 2nd, 4th, 6th, and 24th hours were 57.5%, 83.6%, 93.1%, and 93.1% for Gram-negative bacilli; 12.5%, 42.7%, 76.1%, 97.8% for Gram-positive cocci and 0%, 11.8%, 17.6%, 58.8% for Gram-positive bacilli, respectively. The species-level identification rate was 76.5% for all monomicrobial cultures at the 6th hour. Our results have led us to implement this method into our routine laboratory workflow, and we have started to report rapid identification results for Gram-negative bacteria on the day of blood culture positivity.