Risk of colonisation and infection by extended-spectrum β-lactamase-producing Enterobacterales and carbapenemase-producing Enterobacterales in patients with neutropenia: protocol for the SCREEN-IN multicentre prospective observational study.

INTRODUCTION: Infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) are a major concern in patients with neutropenia with haematological diseases, as they may lead to inadequate empirical therapy and poor outcomes. However, the relationship between intestinal colonisation and subsequent infection in this population remains insufficiently characterised. The SCREEN-IN Study aims to identify factors associated with incident ESBL-E/CPE colonisation and to develop and validate a prediction model for infection caused by these microorganisms in patients with neutropenia. METHODS AND ANALYSIS: SCREEN-IN is a multicentre prospective observational cohort study in 15 hospitals in Spain. Adults admitted to haematology wards who are expected to develop neutropenia after chemotherapy, conditioning for haematopoietic stem cell transplantation or lymphodepleting therapy before CAR-T cell therapy will be enrolled at treatment initiation. Rectal swabs will be obtained at baseline and weekly during neutropenia, including subsequent neutropenic episodes, to assess dynamic colonisation by ESBL-E and CPE. Isolates from surveillance and clinical samples will undergo local phenotypical testing and central molecular characterisation, including whole-genome sequencing to evaluate the relationship between colonising and infecting microorganisms. Participants will be followed for 90 days after the first rectal swab, and each infectious episode will be followed for 30 days. The two co-primary outcomes, analysed separately, are incident ESBL-E/CPE colonisation among participants who are non-colonised at baseline and the first microbiologically documented infection caused by these organisms. Factors associated with colonisation will be analysed using time-to-event methods. Colonisation will be treated as a time-dependent predictor in the infection model, which will undergo internal validation and evaluation in a temporally separated validation cohort. ETHICS AND DISSEMINATION: The protocol was approved by the Provincial Research Ethics Committee of Seville on 24 March 2026. Written informed consent will be obtained from all participants. Results will be disseminated through peer-reviewed journals and scientific meetings. TRIAL REGISTRATION NUMBER: NCT07396571.