This study investigated Gram-negative bacterial isolates and corresponding antimicrobial resistance (AMR) patterns in burn units across the Free State and Northern Cape provinces during the pre-COVID-19, COVID-19, and post-COVID-19 periods. A total of 1 097 isolates were recorded, with the Free State contributing the majority (n=1057) compared to the Northern Cape (n=40). Pseudomonas aeruginosa was the predominant isolate in both provinces, followed by Proteus mirabilis and Acinetobacter baumannii. The Free State demonstrated fluctuating isolate numbers, with notable decreases during COVID-19 and rebounds post-pandemic, whereas the Northern Cape showed a sharp decline in isolates across all periods, likely reflecting reduced specimen collection rather than true epidemiological trends.

AMR analysis revealed province- and species-specific variations. In the Free State, P. aeruginosa resistance increased substantially during COVID-19 (37.39% to 57.49%) before declining post-pandemic, although not to pre-COVID-19 levels. A. baumannii exhibited persistently high resistance across all periods, rising to 88.89% post-COVID-19. Proteus mirabilis showed a gradual decline in resistance, while several Enterobacterales demonstrated reduced resistance post-COVID-19. In the Northern Cape, meaningful trend interpretation was limited due to sample scarcity; however, pre-COVID-19 resistance levels were generally lower than those observed in the Free State.

Overall, the findings indicate that the COVID-19 pandemic substantially influenced bacterial isolation rates and AMR profiles, particularly in the Free State. The sustained high resistance in A. baumannii and elevated resistance in P. aeruginosa underscore the urgent need for strengthened antimicrobial stewardship and targeted infection-control strategies in regional burn units.