A new, virulent and drug-resistant strain of E. coli bacteria is infecting people in the United States and posing a significant public health threat, doctors reported July 30.
The new strain is called ST131 and caused many of the E. coli infections resistant to antibiotics in the fluoroquinolone and cephalosporin classes, the researchers said.
“If this strain gains one additional resistance gene, it will become almost untreatable and will be a true superbug, which is a very concerning scenario,” Dr. James Johnson of the VA Medical Center in Minneapolis, who led the study, said in a statement.
Writing in the journal Clinical Infectious Diseases, Johnson and colleagues said the ST131 strain has been reported in several countries and across the United States.
They tested samples from 127 patients with E. coli infections that resisted strong extended-spectrum cephalosporin and fluoroquinolone antibiotics in 2007. Of these, genetic tests showed 54 were from the new ST131 strain.
“If we could discover the sources of this strain, the transmission pathways that allow it to spread so effectively, and the factors that have led to its rapid emergence, we could find ways to intervene and possibly slow or halt this strain’s emergence,” Johnson said.
Escherichia coli bacteria are normally harmless and are very common, but a few strains can cause severe sickness including diarrhea, urinary tract infections and pneumonia.
The most common source of serious E coli infections is E. coli 0157:H7.
Ground beef has been a common source in the past as the E. coli bacteria are found in the intestines of animals and can be mixed in with raw meat during processing.
“A single E. coli clonal group, ST131, probably caused the most significantly antimicrobial- resistant E. coli infections in the United States in 2007, thereby constituting an important new public health threat,” Johnson and colleagues wrote in their report.