Improving containment and prevention strategies using a patient transfer network representative of patients with multidrug-resistant organisms.

Objectives: Interfacility patient transfers contribute to the regional spread of multidrug-resistant organisms (MDROs). We evaluated whether transfer patterns of inpatients with similar characteristics to carbapenem-resistant Enterobacterales (CRE) case-patients (CRE surrogates) better reflect hospital-level CRE burden than traditionally used populations.

Design: We determined the risk factors for subsequent hospital admission using demographic and clinical information from Tennessee Department of Health tracked CRE case-patients from July 2015 to September 2019. Risk factors were used to identify CRE surrogates among inpatients in the 2018 Tennessee Hospital Discharge Data System (HDDS). Transfer networks of CRE surrogates, Medicare/TennCare beneficiaries, and all-inpatients with ≤365 days of intervening community stays were compared with the transfer networks of CRE case-patients in 2019. The associations between hospital-level CRE prevalence and hospitals' incoming transfer volumes from each network were assessed using negative binomial regression models.

Results: Eight risk factors for subsequent hospital admission were identified from 2,518 CRE case-patients, which were used to match CRE case-patients with HDDS inpatients, resulting in 10,069 surrogate patients. CRE surrogate network showed more structural similarities with the CRE case-patient network than with the all-inpatient and Medicare/TennCare networks. A 33% increase in hospitals' CRE prevalence in 2019 was associated with each doubling of incoming transfer of CRE surrogates in 2018 (adjusted Risk Ratio [aRR] 1.33, 95%CI: 1.1, 1.59), higher than all-inpatient (aRR 1.27, 95% CI: 1.08, 1.51) and Medicare/TennCare networks (aRR 1.21, 95% CI: 1.02, 1.44).

Conclusions: Surrogate transfer patterns were associated with hospital-level CRE prevalence, highlighting their value in MDRO containment and prevention.