The Covid-19 pandemic led to a surge in infections and deaths from antibiotic-resistant "superbugs," reversing years of progress against the challenge, according to a new CDC report.

'Superbug' infections and deaths increased in 2020

As pathogens mutate and evolve, some develop antimicrobial resistance, rendering antibiotics less effective. The World Health Organization has called these drug-resistant pathogens, also known as "superbugs," "one of the top 10 global public health threats facing humanity."

Between 2012 and 2017, dedicated public health efforts reduced antimicrobial-resistant infections by almost 30% in hospitals and 18% overall. However, CDC found that this progress reversed during the first year of the pandemic.

Compared to 2019, hospital-onset infections and deaths from antimicrobial-resistant bacteria increased by at least 15% in 2020. The largest increase in hospital infections came from Acinetobacter, a bacteria that causes wound, bloodstream, and urinary tract infections and pneumonia, with infections jumping 78%.

Similarly, infections from multidrug-resistant Pseudomonas aeruginosa increased 32%, and infections from carbapenem-resistant Enterobacterales (CRE) increased 35%. CRE is sometimes called "nightmare bacteria" and is a major concern who patients who need catheters and other devices, extensive courses of certain antibiotics, or lengthy hospital stays, the Washington Post reports.

Experts said they are particularly worried about the increase in infections from Candida auris, a drug-resistant fungus, which jumped 60%. According to Luis Ostrosky, chief of the infectious diseases division at McGovern Medical School, C. auris "spreads like wildfire," picks up drug-resistant genes from other pathogens, and can mutate to resist antifungal medications.

"The Covid pandemic has many more ramifications than we thought other than Covid infection itself," Ostrosky said. "I think this really confirms our worst fears."

Overwhelmed hospitals struggled with infection control during the pandemic

The increase in antimicrobial-resistant infections in 2020 was likely the result of sick patients overwhelming hospitals, CDC found. Many hospitals struggled with severe staff and supply shortages, particularly of personal protective equipment, which impacted their ability to implement infection controls.

"You have a massive influx of patients who are very much acutely ill, much more than usual for a hospital, and you overwhelm the regular systems. You have to open new units, and you have to staff these units with people who do not usually care for such acutely ill patients," Ostrosky said. "Then you have to cover for the possibility of bacterial infections early on."

In addition, because there were few treatments for Covid-19 in the early days of the pandemic, many doctors initially treated patients' symptoms with antibiotics, which are not effective against viruses. According to CDC's report, almost 80% of Covid-19 patients who were hospitalized between March and October 2020 received antibiotics during their stay. Lengthy courses of antibiotics can give rise to antibiotic-resistant bacteria. 

Overall, more than 29,400 people died from antimicrobial-resistant infections in 2020, 40% of whom acquired the infection while in the hospital. However, experts say the true number of deaths may be much higher, since surveillance and data reporting was limited during the pandemic.

"We don't have the data because our surveillance systems weren't able to even function to provide us that information during the pandemic," said Arjun Srinivasan, CDC's deputy director for program improvement who worked on the report. "That should be every bit as alarming to people as the pathogens that went up. It's just as alarming when you don't know."

CDC's plan to combat antimicrobial-resistant infections

In its report, CDC outlined five key areas of investment to help the United States combat antimicrobial-resistant infections, including:

• Tracking and data, including automating electronic data from the National Healthcare Safety Network

• Preventing infections, including providing high-quality trainings for health care professionals and education for the public

• Antibiotic/antifungal use, including promoting optimal use across health care settings

• Environment and sanitation, including increasing the capacity of the National Wastewater Surveillance System to collect data on antimicrobial-resistant pathogens both domestically and globally

• Vaccines, therapeutics, and diagnostics, including collaborating across agencies to develop new antibiotics, antifungals, and therapeutics

"The COVID-19 pandemic has unmistakably shown us that antimicrobial resistance will not stop if we let down our guard; there is no time to waste," said Michael Craig, director of CDC's Antibiotic Resistance Coordination & Strategy Unit. "The best way to avert a pandemic caused by an antimicrobial-resistant pathogen is to identify gaps and invest in prevention to keep our nation safe." (Sun, Washington Post, 7/12; Weixel, The Hill, 7/12; Sullivan, NBC News, 7/13; Ingram, MedPage Today, 7/12, CDC press release, 7/12)