Unexpected benefit of COVID-19 hospital restrictions: Reduction in patients isolating with multidrug resistant organisms after restrictions were lifted

Background: During the COVID-19 pandemic, measures to prevent microorganism transmission were implemented across hospitals, including wearing compulsory surgical masks, minimising non-urgent procedures and restricting visitors. Previously, concerns have been raised that MRO-associated deaths could rise during a future pandemic through superimposed bacterial infections, inappropriate antibiotic use and reduced focus on preventing MRO infections. Methods: In the state of Queensland, Australia with a population of 5 million, only a short first wave of coronavirus cases occurred and restrictions were quickly scaled back. This presented a natural experiment of pre-, during and post-COVID-19 restriction timings to evaluate the effectiveness of heightened prevention measures on multidrug resistant organism (MRO) infections. Patient isolation days and MRO types were collected weekly from routine infection control reports, at a large public hospital, from 28th January 2020 to 24th July 2020. In this interrupted time series design, we employed Poisson mixed effect regression modelling to evaluate the difference in incidence of patient isolation days between time periods. Results: Compared to pre-COVID, patient isolation days reduced during COVID restrictions (incidence rate ratio 0.65, 95%CI: 0.59, 0.70; p < 0.001) and increased again post-COVID restrictions, but did not return to pre-COVID levels (0.87, 95%CI: 0.80, 0.95; p = 0.001). The efficiency of isolating patients improved after COVID-19 with fewer bed closures required. Conclusion: Heightened infection control awareness, hand sanitation and mask wearing after COVID-19 restrictions were lifted appear to effectively prevent common hospital-acquired MRO infections.