Exploring the evolution of Acinetobacter baumannii and Pseudomonas aeruginosa resistance during the COVID-19 era

In our study, we aim to compare the resistance profiles of Acinetobacter baumannii and Pseudomonas aeruginosa isolates from intensive care unit (ICU) patients before and during the COVID-19 pandemic.

The study involved adult patients monitored in the ICUs of a secondary-level hospital from January 2019 to December 2022. Isolates of A. baumannii and P. aeruginosa were obtained from blood, urine, and respiratory samples. Identification and antibiotic susceptibility tests were conducted using the disk diffusion method and the VITEK 2 system.

The average age of the patients was 61.3 ± 21.9 years (range: 18-95), with a majority of 1306 (51.6%) being male. During the pandemic, A. baumannii isolates showed a significant increase in resistance rates for several antibiotics compared to the pre-pandemic period: imipenem (96% vs 35.1%), amikacin (84.1% vs 14.4%), ciprofloxacin (96.9% vs 36.9%), trimethoprim-sulfamethoxazole (66.4% vs 27%), and ceftazidime (96.5% vs 33.3%) (all with P < .001). However, there was no significant change in colistin resistance rates in these isolates (0.9% vs 0%; P = .307). Similarly, Pseudomonas aeruginosa isolates exhibited significant increases in resistance rates during the pandemic compared to the pre-pandemic period: imipenem (51.5% vs 18.8%; P < .001), colistin (4.9% vs 0.6%; P = .009), amikacin (23.5% vs 4.4%; P < .001), ciprofloxacin (53.3% vs 13.8%; P < .001), and ceftazidime (39.2% vs 12.7%; P < .001).

Our results demonstrate a significant increase in antibiotic resistance levels in Acinetobacter and Pseudomonas strains associated with hospital-acquired infections or colonization during the COVID-19 pandemic.