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

Background: Patient transfers between hospital departments and wards frequently occur, and bring with them the risk of inter-department transmission of antibiotic-resistant bacteria (ARB). These bacteria form a risk to the patients already susceptible to colonisation and infection.

Aim: Goal of this study is to assess the impact of the SARS-CoV-2 pandemic on the intra-hospital network of a large German university hospital.

Methods: Using data collected from the hospital between 2019 and 2023 we developed a model to represent an intra-hospital transfer network with all patient movements among all the wards, by creating a time-sliced temporal network for each month. We described the network and assessed its robustness against ARB spread by simulating outbreaks among wards.

Findings: Over the years studied, we found that in April 2020, when many elective surgeries were cancelled due to the SARS-CoV-2 pandemic, the robustness of the network strongly increased in comparison to all other months. Despite the network being relatively stable over the study period, it was affected by an internal change of hospital structure due to a hospital merging event.

Conclusion: The intra-hospital transfer network was affected by external influences due to the pandemic, slowing down the potential spread of the nosocomial pathogens. The network was generally stable and quickly recovered, although an internal force affected the structure of the network. A better understanding of the influence of patient transfers will help to design intervention strategies against the spread of antimicrobial resistance within hospitals.