The Impact of the COVID-19 Pandemic on Antimicrobial Resistance Trends in a Tertiary Care Teaching Hospital: A Ten-Year Surveillance Study.

Background/

Objectives

The COVID-19 pandemic accelerated the inappropriate use of antibiotics, amplifying the global threat of antimicrobial resistance (AMR), particularly in resource-limited healthcare settings. This study investigated AMR patterns in a tertiary care hospital, focusing on the impact of the COVID-19 pandemic on invasive bacterial pathogens.

Methods

This retrospective observational study was conducted at the University Clinical Centre of the Republic of Srpska, analyzing AMR data from invasive bacterial isolates collected between 2015 and 2024, and assessing correlations between antibiotic utilization and resistance patterns during the study periods.

Results

Among 4718 invasive bacterial isolates, Acinetobacter spp. (26.7%) and K. pneumoniae (20.8%) were the most prevalent. A significant increase in invasive isolates was observed during the COVID-19 period, particularly for K. pneumoniae (p = 0.003), P. aeruginosa (p = 0.017), Acinetobacter spp. (p = 0.013), and E. faecium (p = 0.028). The highest multidrug-resistant (MDR) rates were observed in Acinetobacter spp. (97% during COVID-19) and K. pneumoniae (>80% post-COVID-19). Resistance increased significantly in K. pneumoniae to cephalosporins, fluoroquinolones, and carbapenems, and in P. aeruginosa and Acinetobacter spp. to carbapenems, while P. aeruginosa resistance to aminoglycosides declined. Strong correlations were found between carbapenems use and Acinetobacter spp. resistance (r = 0.861, p = 0.001), and vancomycin use and E. faecalis resistance (r = 0.798, p = 0.006). Moderate correlations were also observed between carbapenems use and resistance of K. pneumoniae and P. aeruginosa.

Conclusions

These findings highlight the profound impact of the COVID-19 pandemic on AMR dynamics, particularly among Gram-negative pathogens, and underscore the urgent need for strengthened antimicrobial stewardship and targeted surveillance to curb the spread of MDR pathogens, especially in resource-limited hospitals.