U.S. woman contracts infection resistant to last-resort antibiotic

In April, a Pennsylvania patient was being treated for a urinary tract infection when her physicians discovered she had a strain of colistin-resistant E. coli. Colistin is the industry’s “fallback” antibiotic, only used when bacteria are resistant to all other forms of antibiotics. The discovery means an antibacterial-resistance exists for every type of antibiotic, creating the risk of an infection invulnerable to all antibiotic treatments.

Antimicrobial Agents and Chemotherapy reported that the E. coli’s colistin resistance came from a gene called mcr-1. The mcr-1 gene and its corresponding drug resistance can be shared between bacteria, potentially creating entire strains of colistin-resistant infections. Researchers say that when combined with other forms of sharable antibiotic-resistance, mcr-1 could result in the first infection that’s completely invulnerable to all forms of antibiotics. 

"The recent discovery of a plasmid-borne colistin-resistance gene,mcr-1 heralds the emergence of truly pan-drug resistant bacteria," the study’s authors wrote.

The first reported case of colistin resistance happened last fall, in China. Since then, it has spread to other countries, though many are alarmed that it reached the U.S. this quickly. No one is sure how the Pennsylvania patient came in contact with the mcr-1 gene.

“I do not like knowing that … [this] is now circulating here in the US,” said Beth Bell, MD, director of the National Center for Emerging and Zoonotic Infectious Diseases, in an interview with Stat News. “It is a very unfortunate example of what we’ve been saying about how dangerous this antibiotic resistance phenomenon really is.”

Despite the World Health Organization designating colistin as critically important for human medicine, farmers in many nations still use the drug on livestock, including in China. Two million Americans are infected annually infected by antimicrobial-resistant (AMR) infections, with 23,000 people dying as a direct result of their infections. A recent study of Washington, D.C. area hospitals found that 5.1% of patients carried had carbapenem-resistant Enterobacteriaceae infections, which can kill up to 50% of those infected. On the international stage, the United Kingdom published a report estimating that AMR infections could kill up to 10 million annually by 2050.