A Hospital Relates Rise in Antimicrobial Resistance to Pandemic

One hospital related the evolution of resistant Acinetobacter baumannii and Pseudomonas aeruginosa in its ICU to the COVID-19 pandemic.

This illustration depicts a three-dimensional (3D) computer-generated image of three multidrug-resistant, Pseudomonas aeruginosa bacteria. The artistic recreation was based upon scanning electron microscopic (SEM) imagery. Note the presence of numbers of thin, diaphanous fimbriae emanating from the organisms’ cell wall, as well as a single, corkscrew-shaped flagellum, which provides the bacteria with a unipolar mode of motility.

Image credit: Jennifer Oosthuizen

This is part of an ongoing series looking at the effects of the pandemic 5 years from its start.

Rates of resistance to multiple antimicrobials in Acinetobacter baumannii and Pseudomonas aeruginosa from blood, urine and respiratory samples of patients in 1 intensive care unit (ICU) increased significantly with the onset of the COVID-19 pandemic.

Both organisms have been implicated in noscomial infections globally, particularly in ICUs.The investigators at the Gazi State Hospital in Samsun, Turkey sought to ascertain changes in resistance from isolates tested from January 2019 through December 2022. Identification and antibiotic susceptibility were determined with both traditional biochemical methods and the VITEK 2 system (bioMérieux, France).

"Year-to-year comparisons indicated that resistance rates were significantly lower in 2019 compared to subsequent years, with no substantial change observed between 2020 and 2022," reported Emine Sehmen, MD, Department of Clinical Microbiology and Infectious Disease, Gazi State Hospital.¹

"This suggests that the notable surge in resistance rates occurred at the onset of the pandemic but did not persist throughout its duration.Contrary to the typical upward trend in resistance rates over time, this phenomenon implies a direct impact of the pandemic on bacterial resistance patterns," indicate Sehmen et al.

The 5-year Anniversary of the Pandemic Series

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Significant increase in resistance rates were observed for both organisms during the COVID-19 pandemic compared to the pre-pandemic testing. For A bauannii isolates, the rate of resistance to imipenem rose to 96% from prepandemic rate of 35.1%. Other increased rates of resistance were to: 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%. Sehmen and colleagues noted, however, that there was no significant change in resistant rates to colistin (0.9% vs 0%).

P aeruginosa isolates demonstrated increased rate of resistance to imipenem (51.5% vs 18.9%); colistin (4.9% vs 0.6%), amikacin (23.5% vs 4.4%), ciprofloxacin (53.3% vs 13.8%), and ceftazidime (39.2% vs 12.7%). Although a significant increase in rates of resistance was found for both organisms between prepandemic and the pandemic periods, there was no statistically significant changes in resistance rates between 2020 and 2022.

Sehmen and colleagues attribute the surge in rates of resistance with onset of the pandemic to several factors, including higher admissions to ICUs, prolonged hospital stays, increased utilization and duration of mechanical ventilation and oxygen support.

"During the pandemic period, the high demand in ICUs necessitated the rotation of physicians from various specialties. Consequently, rational antibiotic practices often fell outside the control of infectious disease specialists," the investigators observed.

"Broad spectrum antibiotics were initiated as the first-line treatment option and could not be de-escalated," they recounted. "We hypothesize that this is a primary factor contributing to the development of resistance."

In addition to implicating extensive use of broad-spectrum antibiotics during the crisis of the pandemic as a primary factor for the surge in rates of resistance, they note that noscomial infections caused by these and other non-fermentative gram-negative bacteria have limited treatment options, and emphasize the importance of closely monitoring resistance patterns.

"Revisiting rational antibiotic use and implementing stringent infection control strategies are crucial in mitigating this resistance," Sehmen and colleagues declare. "Emerging diagnostic biomarkers, such as procalcitonin, may offer potential in guiding stewardship during such crises. Restoring specialist oversight in antibiotic selection and utilization is essential to curb the progression of antibiotic resistance."

Reference

1.Sehmen E, Yilmaz EM, Pusa SY, et al. Exploring the evolution of Acinetobacter baumannii and Pseudomonas aeruginosa resistance during the COVID-19 era. Antimcrob Steward Healthc Epidemiol. 2025. doi:10.1017/ash.2025.46. Accessed April 3, 2025.