COVID-19 Pandemic May Have Accelerated Antimicrobial Resistance

Approximately 1.2 million people die each year of antibiotic-resistant infections, a figure projected to increase 10-fold by 2050. Antimicrobial resistance is largely caused by using excessive, unnecessary antibiotics, which allows harmful pathogens to mutate and develop resistance.

One study, presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), examined how the COVID-19 pandemic affected the growing threat of antimicrobial resistance (AMR). Increased use of antibiotics during the pandemic reportedly caused AMR secondary infections, so investigators sought to verify or disprove the theory that AMR increased with the outbreak of COVID-19.

The study was led by doctors Karri Bauer of Merck & Co., and Vikas Gupta of Becton Dickinson. The multicenter, retrospective, cohort study included adults 18 and older who were admitted to 1 of 271 hospitals before and during the COVID-19 pandemic.

The pre-pandemic period ran from July 1, 2019-February 29, 2020, and the pandemic period included patients admitted from March 1, 2020-October 30, 2021. All hospital admissions with 1 or more AMR infections, defined as a first positive culture for select gram-negative or gram-positive antibiotic-resistant pathogens, were recorded.

The investigators calculated AMR rates per 100 admissions in the pre-pandemic and pandemic periods, assessing whether drug-resistant infections were community-onset or hospital-onset.

The AMR rate was 3.54 per 100 admissions before the pandemic and 3.47 per 100 admissions during the pandemic. Notably, however, patients who tested positive or negative for COVID-19 had higher levels of AMR than patients before the pandemic: 4.92 per 100 admissions in comparison to 4.11 per 100 admissions.

Additionally, the investigators found that hospital-onset cases of drug-resistant infections were significantly higher during the pandemic than in the pre-pandemic period. For hospital-acquired infections, the AMR rate was 0.77 per 100 admissions before the pandemic, and 0.86 per 100 admissions during the pandemic.

“It is particularly worrying that antibiotic resistance has been rising during the pandemic in both SARS-CoV-2 positive and negative patients,” said presenting author Bauer. “Hospital-acquired infections are a major concern, with antimicrobial resistance rates significantly higher during the pandemic than before.”

This study, “US study suggests COVID-19 pandemic may be accelerating antimicrobial resistance,” was presented during the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal, April 23-26, 2022.