Multidrug-Resistant E Coli on the Rise in the US

By Will Boggs, MD

August 21, 2020

NEW YORK (Reuters Health) - Multidrug resistance among Escherichia coli causing device- and procedure-related healthcare-associated infections (HAIs) has increased in the U.S., according to findings from the National Healthcare Safety Network (NHSN).

"One of the interesting findings was that, while resistance to the fluoroquinolone class of antibiotics remained relatively stable over the course of 5 years, resistance to extended-spectrum cephalosporins increased over this same time," said Dr. Athena P. Kourtis of the Centers for Disease Control and Prevention, in Atlanta, Georgia.

"This is a worrisome trend, as this class of antibiotics is used widely for invasive infections, because they are powerful antibiotics and are relatively safe," she told Reuters Health by email. "Not having this option in our therapeutic armamentarium can make treatment of such hospital infections very challenging."

E. coli, the most common microorganisms responsible for HAIs in U.S. hospitals, is becoming increasingly resistant to multiple antibiotics.

Dr. Kourtis and colleagues used NHSN data from 2013 to 2017 to examine the epidemiology of multidrug-resistant E. coli responsible for device- and procedure-related HAIs in acute-care hospitals, long-term acute-care hospitals and inpatient rehabilitation facilities.

Nearly 97,000 E. coli isolates were included in the analysis, most commonly in association with catheter-associated urinary-tract infections (CAUTIs, 54%), surgical-site infections (SSIs, 35%), and central-line-associated bloodstream infections (CLABSI, 10%).

The prevalence of E. coli resistant to fluoroquinolones (FQ) rose from 34% in 2013 to 35% in 2017 (P<0.0001), while resistance to extended-spectrum cephalosporins (ESC) increased from 14% to 19% (P<0.0001).

The proportion of isolates resistant to both ESC and FQ increased from 11% in 2013 to 14% in 2017, and concurrent resistance to ESC, FQ, and aminoglycosides (AG) increased from 4% to 5%, also significant increases, the researchers report in Clinical Infectious Diseases.

The Northeast region had the highest prevalence of ESC/FQ coresistance (>13%), and the highest prevalence of ESC/FQ coresistant phenotypes was 33%, reported in Mesa, Arizona (2015) and Miami, Florida (2016).

Factors significantly associated with concurrent ESC/FQ resistance among E. coli isolates included male sex, CLABSI, long-term acute-care hospitals (LTACH), and more recent years (compared with earlier years). CLABSI and LTACH were associated with concurrent resistance to ESC/FQ/AG.

"Even though our analysis looked at hospital infections, resistance is rising among infections outside the hospital, too," Dr. Kourtis said. "For the physician, knowing the local patterns of resistance in their community and hospital where they practice is very important in deciding what antibiotics to use."

"Using antibiotic stewardship, which means to use the right antibiotic at the right time and for the right duration, and only when it is indicated, is effective in reducing resistance in bacteria," she said.

Dr. Kourtis added, "Antibiotic resistance moves from healthcare setting to healthcare setting through patients, and infection prevention in the healthcare setting is as important as antibiotic stewardship efforts in decreasing antibiotic resistance."

"Further characterization of coresistance phenotypes with strain type, infection rates, and clinical outcomes may inform targeted prevention strategies for particular healthcare facilities/networks," the authors conclude. "Moreover, it can also encourage infection prevention specialists, as well as clinicians and others involved in antibiotic stewardship efforts, to help direct and monitor use of agents that are used as first-line agents for empiric treatment or prophylaxis."

SOURCE: Clinical Infectious Diseases, online July 23, 2020.