Impact of the SARS-CoV-2 pandemic on hospital robustness to the spread of antibiotic-resistant bacteria in a large German university hospital

Background: Patient transfers occur frequently between hospital departments and wards, and bring with them the risk of interdepartmental transmission of antibiotic-resistant bacteria (ARB). These bacteria form a risk to patients already susceptible to colonization and infection. Aim: To assess the impact of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic on the intrahospital network of a large German university hospital. Methods: Using data collected from the hospital between 2019 and 2023, a model was developed to represent an intrahospital transfer network with all patient movements between all wards by creating a time-sliced temporal network for each month. The network was described, and its robustness against the spread of ARB was assessed by simulating outbreaks between wards. Findings: In April 2020, when many elective surgeries were cancelled due to the SARS-CoV-2 pandemic, the robustness of the network increased strongly in comparison with all other months. Despite the network being relatively stable over the study period, it was affected by an internal change in hospital structure due to a hospital merger. Conclusion: The intrahospital transfer network was affected by external influences due to the SARS-CoV-2 pandemic, slowing down the potential spread of nosocomial pathogens. The network was generally stable and recovered quickly, although an internal force affected the structure of the network. A better understanding of the influence of patient transfers will help in the design of intervention strategies against the spread of antimicrobial resistance within hospitals.