Efficacy of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for Rapid Bacterial Identification of Positive Blood Culture Short term incubation for bacterial identification

Abstract

The main objective of this study was to evaluate the identification of microorganisms from positive blood cultures by using the Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry. In this prospective study, positive blood cultures were collected between March and November 2019 at the Prince Mohammed bin Nasser Hospital in Jazan. Rapid identification by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry was obtained the same day from blood agar plates after a shortened incubation period of a maximum of three hours.

Two-hundred ninety-three (73.6%) isolated micro-organisms were correctly identified, of which 198 (67.57%) were Gram-positive and 95 (32.42%) Gram-negative. Incorrectly identified ones were obtained from young colonies where the Matrix-Assisted Laser Desorption/Ionization score was < 2 in 68 bottles. A polymicrobial-blood stream infection was observed in 11 (1.6%) cases only. Our data demonstrated a high rate of identification of microorganisms within three hours of subculturing of positive blood culture bottles.