A nomogram for assessing secondary infection risk in hospitalized patients with intestinal CRE colonization: a prospective cohort study

OBJECTIVE: To investigate the epidemiology, risk factors, and molecular characteristics of intestinal carbapenem-resistant Enterobacterales (CRE) colonization and subsequent secondary infections in a hospital setting, and to develop a predictive model for risk stratification. METHODS: A large-scale, unbiased active screening for intestinal CRE carriage was conducted among patients (including physical examination, outpatient, and inpatient populations) between August 31, 2021, and February 28, 2022. A prospective cohort design was used to follow colonized inpatients for six months. Clinical data were collected for univariate and multivariate logistic regression analysis to identify independent risk factors for infection. A nomogram prediction model was constructed and validated. Homology between colonizing and infecting isolates was assessed using WGS and MALDI-TOF MS analysis. RESULTS: The overall CRE colonization rate was 4.95% (475/9,615), with significant variation between inpatients (5.55%), outpatients (3.97%), and physical examination subjects (3.54%). Escherichia coli (49.05%) and Klebsiella pneumoniae (46.95%) were the dominant species. The overall secondary infection rate among colonized inpatients was 5.04% (18/357), with the highest rates observed in the Rehabilitation (30.00%), ICU (21.88%), and Neurology (20.00%) departments. Multivariate analysis identified ICU stay ≥ 48 h, carbapenem exposure, fecal incontinence, and tracheostomy as independent risk factors, while admission to Rehabilitation was a protective factor. The prediction model demonstrated high discriminative ability (AUC = 0.960) in this single-center derivation cohort, but external validation is required before clinical application. Molecular analysis revealed that ST11 CRKP was the predominant clone (70%), and most infections (12/18) were genetically homologous to the patient's colonizing strain. CONCLUSION: CRE intestinal colonization is prevalent across healthcare settings. The progression from colonization to infection is driven by specific clinical risks, which can be used to assess risk by our novel nomogram. These findings underscore the need for targeted screening in high-risk departments, enhanced antimicrobial stewardship, and focused surveillance on dominant clones like ST11 CRKP to effectively prevent CRE transmission and infection.