Hospital-acquired infection rates remain high even after the pandemic

Hospital-acquired infections associated with antimicrobial resistance (AMR) increased by 32% during the COVID-19 pandemic and remain 13% higher after the pandemic compared to before, found a study of US hospital data comparing AMR levels before, during and after the pandemic.

The largest increase in infections was due to gram-negative, carbapenem-resistant bacteria. Acinetobacter baumannii, Pseudomonas aeruginosaIn the Enterobacteriaceae family, levels increased by more than 50% during the pandemic compared to pre-pandemic levels and remained 35% higher than pre-pandemic levels in 2022.

This year, Christina Yeck, MD, of the National Institute of Allergy and Infectious Diseases, European Society for Clinical Microbiology and Infectious Diseases World Congress (Formerly ECCMID).

There are several reasons why the incidence of carbapenem-resistant infections caused by gram-negative bacteria is high, Jek said. Medscape Medical News“During the pandemic, there has been a sharp increase in empirical and inappropriate antibiotic use. Gram-negative bacteria are more susceptible to acquiring resistance via plasmids, for example, and we suspect that exposure to antibiotics in patients and their surroundings may have encouraged the development of Gram-negative resistance,” she said. But it could also be due to the relative ease of detection compared to other infections. “These infections are more severe and more likely to be transmitted.”

The study also found that hospitals with a high or rapidly increasing number of critically ill COVID-19 patients have seen the largest increases in hospital-acquired AMR transmission, even in larger hospitals with more beds. Yek added that these data do not yet take into account the heightened risk of hospital-acquired AMR transmission among COVID-19 patients and other critically ill patients, which will be addressed in the next phase of the analysis.

Data from before, during and after the pandemic

Data on adult patients was collected from 120 US hospitals through the PINC-AI database and relates to the pre-pandemic (January 2018 to December 2019), pandemic (March 2020 to February 2022) and post-pandemic (March 2022 to December 2022) periods. Staphylococcus aureusvancomycin resistance Enterococcusextended-spectrum cephalosporin-resistant Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Baumann (CRAB), carbapenem resistant Pseudomonas aeruginosa (CRPA).

Yek explained that their study was based on data from the Centers for Disease Control and Prevention, which reported a 12% increase in hospital-acquired resistant infections in the first year of the pandemic. Yek wanted to extend the study period into 2021, when hospitals saw a surge in COVID-19 patients compared to 2020.

“During these surges, hospitals were overwhelmed not only with COVID-19 patients but also with other patients. Our group looked at surges and associated mortality in US hospitals and combined these data to ask, given the increase in antimicrobial resistance (AMR) and the increase in the number and size of COVID-19 surges, how will these factors interact in 2020-2021 and 2021-2022,” explained Yeck.

Patterns of COVID surges, hospital volumes and AMR

During the pandemic, the overall prevalence of AMR infections increased by 6.3% (from 181.9 to 193.3 per 10,000 hospitalizations), mainly due to a sharp increase in hospital-acquired resistant infections, which increased by at least 32%, whereas community-acquired resistant infections increased by only 1.4% over the same period.

The increase was driven largely by resistant Gram-negative bacterial infections, which increased by approximately 20% compared to pre-pandemic levels, while resistant Gram-positive bacterial infections decreased by 4.2%. Notably, hospital-acquired CRAB increased the most (+151.1%), followed by hospital-acquired CRE (+62.2%) and CRPA (+54.2%).

Yek said the link between the COVID surge and hospital-acquired gram-negative carbapenem-resistant bacteria could be due to several factors. “Various groups have hypothesized that COVID patients have different physiology due to their immunosuppressed state, they have more comorbidities, and they have more invasive interventions such as central venous lines,” Yek said. These are all risk factors for hospital-acquired infections.

Other research groups have also shown that while COVID-19 patients are at higher risk for infection, non-COVID patients are too, she added, “so we can't just blame it all on COVID-19. There's something else going on.”

The study also looked at the impact of hospital size and hospital COVID-19 patient surges. Larger hospitals with more beds had higher rates of hospital-acquired AMR. Patients in hospitals with 100-199 beds were 1.25 times more likely to be infected than patients in hospitals with fewer than 100 beds, and patients in hospitals with more than 500 beds were 2.44 times more likely to be infected.

Hospitals that have experienced a surge in COVID-19 patients have also seen an increase in antimicrobial-resistant (AMR) infections. “The probability increases stepwise as the surge patient burden and hospital size increases,” Jek said, adding, “One caveat is that larger hospitals tend to have more severe cases and intensive care units, but that's not taken into account here.”

“These findings are a major step forward for the treatment of cancer,” said David Greenberg, MD, of UT Southwestern Medical Center in Dallas, Texas. Medscape Medical News The increase in Gram-negative infections is not surprising as they are generally increasing and were increasing even before the pandemic, but this study is a reminder that viral pandemics, whether COVID or influenza, can have secondary effects beyond the viral infection itself, and AMR has downstream effects.

“We've known about secondary infections for some time, but this discovery is a reminder that viral pandemics can also cause secondary infections, especially if they are caused by drug-resistant bacteria. With antibiotic resistance on the rise around the world, this is only going to become more common following viral pandemics,” Greenberg said.

Messrs. Yeck and Greenberg did not disclose any relevant financial information.