Impact of rapid MALDI-TOF MS and susceptibilities on hospitalized children with Gram-negative bloodstream infections.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers fast identification to improve time to appropriate antibiotics in Gram-negative bloodstream infections (GN-BSIs). This retrospective study evaluated patients with GN-BSI PRE- and POST-implementation of rapid identification with and without direct antimicrobial susceptibility testing (AST). Patients aged 0-18 years with GN-BSI before and after implementation of direct blood culture broth MALDI-TOF MS and AST were evaluated. Cohorts were defined by methods of organism identification and AST: traditional culture and AST methods (PRE), direct from broth identification by MALDI-TOF MS with culture-dependent AST (MALDI + cAST) and direct from broth identification MALDI-TOF MS with direct AST (MALDI + dAST). A total of 246 pediatric patients were included, 78 PRE, 92 MALDI + cAST, and 76 MALDI + dAST. Both POST-implementation groups had decreased median time from blood culture collection to identification by over 24 h (16.1 h MALDI + cAST and 15.5 h MALDI + dAST vs 42.9 h PRE;