Integrating rapid diagnostics in Gram-negative bloodstream infections of patients colonized by carbapenemase-producing Enterobacterales

We implemented a fast-track diagnostic approach for Gram-negative bloodstram infections (BSIs) among carbapenemase-producing Enterobacterales (CPE) carriers. Within a large cohort of patients with CPE rectal carriage, 18.1% developed Gram-negative BSIs, of which 69.5% were caused by CPE. Direct matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis provided reliable identification in 97% and 53.8% of monomicrobical blood cultures positive to Enterobacterales and non fermenting Gram-negative species, respectively. Overall, sensitivity and specificity of NG-Test Carba 5 compared with the composite reference method after discrepant analysis were 100%, in polimicrobial blood cultures too. The combined use of direct MALDI-TOF MS and NG-Test Carba 5 assay might be a reliable and cost-effective tool for accelerating the laboratory diagnosis of CPE BSI in cohorts of high-risk patients such as CPE carriers.