Scientists may have identified a second patient in the United States infected with bacteria carrying the mcr-1 “superbug” gene, which makes bacteria highly resistant to a last-resort class of antibiotics, according to a report from Reuters. The gene is believed to have been found in a sample of Escherichia coli bacteria from a patient in New York. The finding follows the discovery last month of a woman in Pennsylvania who had a urinary tract infection caused by E. coli that carried the gene.
The discovery was scheduled to be published on June 27 in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology, but the editors at the journal decided to withhold it from publication because the study authors wanted to verify the data. A journal spokeswoman said the authors are expected to confirm the results within a week.
The mcr-1 gene makes bacteria resistant to colistin, an antibiotic used to treat multidrug-resistant infections, including carbapenem-resistant enterobacteriaceae (CRE), which U.S. health officials have dubbed “nightmare” bacteria.
Bacteria have the ability to share resistance genes, and U.S. officials are worried that the mcr-1 gene may find its way into CRE bacteria, potentially creating bacteria that are resistant to virtually all types of antibiotics.
Scientists have been tracking the movement of the mcr-1 gene around the globe since it was discovered last year in people and pigs in China.
Researchers tested 13,525 E. coli and 7,481 Klebsiella pneumoniae strains from patients collected last year from hospitals in the Asia–Pacific region, Latin America, Europe, and North America. Of these strains, 390 (1.9%) were resistant to colistin, and 19 of these isolates tested positive for the mcr-1 gene. The data are now being checked for accuracy.
Samples carrying the mcr-1 gene came from 10 countries. Only one sample came from the U.S. It involved a New York patient infected with E. coli whose name and condition were not disclosed.
In the U.S., antibiotic resistance causes at least 2 million illnesses and 23,000 deaths annually.
Source: Reuters; June 27, 2016.