Multifunctional Bimetallic Nanoreactors for Integrative Host‐Pathogen Analysis Toward Bloodstream Infection Diagnosis

Abstract Bloodstream infections (BSIs) annually claim millions of lives, contributing to one‐third of global mortality. Mortality rates predominantly depend on the duration between symptom onset and the administration of appropriate antibiotics. Clinical protocols for identifying pathogens typically take a 2–5 day wait for blood culture, due to the limited pathogen load present in blood at the initial stage. Currently, stratifying infections into high‐risk subpopulations and administering prompt therapy rely on separate platforms. Here, multifunctional bimetallic nanoreactors are designed to develop a rapid platform for integrative analysis of both host and pathogen characteristics directly from blood samples. These nanoreactors enable colorimetric quantitation of host immune responses and mass spectrometric profiling of pathogen metabolic fingerprints. The platform predicts BSI in 100% of suspected cases and achieves 91.67% match in species identification within a 60 min sample‐to‐answer time, holding promise for implementation in clinical practice.