Clinical impact of matrix‐assisted laser desorption ionization‐time of flight mass spectrometry combined with antimicrobial stewardship interventions in patients with bloodstream infections in a Japanese tertiary hospital

BACKGROUND: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has the potential to permit early organism identification and optimization of antibiotic therapy. However, MALDI-TOF MS combined with antimicrobial stewardship is available at only a limited number of institutions. Here, we evaluated the clinical impact of implementing MALDI-TOF MS combined with antimicrobial stewardship intervention in patients with bloodstream infections. METHODS: We conducted a single-centre, prospective cohort study to evaluate the clinical impact of implementing MALDI-TOF MS combined with antimicrobial stewardship intervention in patients with bloodstream infections. Processes and clinical outcomes in patients with bloodstream infections were compared before and after implementation of MALDI-TOF MS. RESULTS: Compared with the conventional identification method, MALDI-TOF MS combined with antimicrobial stewardship intervention significantly decreased the time to organism identification (48.6 ± 46.0 hours vs 78.1 ± 38.9 hours, P < 0.001), effective antimicrobial therapy (12.9 ± 19.0 hours vs 26.2 ± 44.8 hours, P < 0.001) and optimal antimicrobial therapy (53.3 ± 55.0 hours vs 91.7 ± 88.7 hours, P < 0.001. Moreover, the rate of clinical failure (14.0% vs 33.3%, P < 0.001) and incidence of adverse events (7.5% vs 23.9%, P < 0.001) was lower in the MALDI-TOF MS group than in the conventional identification group. A multivariate Cox proportional hazard analysis indicated that implementation of MALDI-TOF MS was a protective factor against clinical failure in patients with bloodstream infections (hazard ratio, 0.61; 95% confidence interval, 0.38-0.99; P = 0.047). CONCLUSIONS: Implementation of the MALDI-TOF MS combined with antimicrobial stewardship intervention facilitated early optimization of antimicrobial therapy with a remarkable concomitant reduction in clinical failure and adverse events in patients with bloodstream infections.