June 14 (UPI) -- The gene that makes salmonella resistant to antibiotics of last resort has finally made its way from Asia to the United States, a new study says.
Researchers isolated the gene mcr-3.1 in a patient who had traveled to China two weeks before falling ill to salmonella, according to research published in the June edition of the Journal of Medical Microbiology.
They found the gene after genome sequencing 100 human stool samples collected between 2014 and 2016.
"This gene was already in the USA since 2016, which is surprising," Siddhartha Thakur, the director of global public health at North Carolina State University, told UPI. "Colistin is the last resort drug and if the gene for resistance jumps on a plasmid then it spreads faster."
According to Thakur, the gene made its way from a chromosome to a plasmid in China. This illustrated the possibility it could move back and forth between organisms.
So far, the gene has spread to 30 different countries, Thakur says, illustrating its transmission capability. Of the more than 2,500 salmonella serotypes in existence, Salmonella enterica causes much of the sickness related to the disease in the United States.
"This is exactly what we have seen in our study. It is possible that this gene has spread even more than what we had imagined," Thakur said. "The major consequence is that we are running out of drugs to treat multi-drug resistant infections. This will lead to higher mortality."