Difference in impact of coinfections on antibiotic use in patients hospitalized with COVID- 19 between the Omicron-dominant period and the pre-Omicron period

Abstract

Abstract Background Excessive antibiotic use in patients with coronavirus disease 2019 (COVID-19) can cause an increase in multidrug-resistant (MDR) organisms. This study evaluated antibiotic stewardship during the COVID-19 pandemic. Methods Antibiotic use in patients with COVID-19 was compared in a community hospital between 2022 when the Omicron variant was prevalent (n = 225) and 2021 when previous variants were prevalent (n = 257). Antibiotics were categorized as antibiotics predominantly used for community-acquired infections (CAIs) and antibiotics predominantly used for health care-associated infections (HAIs), and days of therapy per 100 bed days (DOT) was evaluated. Results Patients during the Omicron period were older and had more comorbidities. The rate of critically ill patients was around 10% in both periods. During the pre-Omicron period, > 90% of hospitalized patients were unvaccinated, whereas 41.8% of patients received a booster dose during the Omicron period. Ground-glass opacities, bilateral shadows, and a peripheral distribution on CT were observed in most patients in the pre-Omicron period and there were significant differences in comparison with the Omicron period. Although only 0.9% of patients had bacterial coinfection on admission in the pre-Omicron period, 38.9% of patients had the coinfection during the Omicron period and were less likely to receive COVID-19-directed therapy. Coinfection before /after admission was an independent risk factor for composite adverse events in both periods (odds ratio [OR] 3.77, 95% confidence interval [CI] 1.13–12.59, and OR 9.15, 95% CI 3.85–21.74). DOT in antibiotics for CAIs were significantly fewer in the COVID-19 ward than in general wards in the pre-Omicron period but increased in the Omicron period (from 3.60 ± 3.15 to 17.83 ± 10.00). Numerically lower DOT of antibiotics for HAIs was demonstrated in the COVID-19 ward than in the general wards (pre-Omicron, 3.33 ± 6.09 versus 6.37 ± 1.10; Omicron, 3.84 ± 2.93 versus 5.22 ± 0.79). No MDR gram-negative organisms were isolated in the COVID-19 ward. Conclusions Antibiotic use on admission was limited in the pre-Omicron period but increased in the Omicron period because of a high coinfection rate on admission. Excessive use of antibiotics for HAIs was avoided during both periods.