Los Angeles County Health authorities issued a national biorisk warning on Tuesday after identifying a patient infected with the 100 percent drug-resistant “mcr-1” bacterial pathogen, apparently acquired through international travel.

Scientists first reported the emergence of the plasmid-encoded mcr-1 gene, which is completely resistant to all known drugs in a Pennsylvania female patient with a urinary tract infection in November 2015. The discovery set off a worldwide biorisk warning from the World Health Organization, causing bacteriologists to scour their international “collections” of thousands of frozen bacterial isolates in search of any similar gene DNA.

The British Lancet medical journal reported last May that English and Chinese microbiologists had found almost 100 instances of the biorisk gene. With some of the frozen samples going back over five years, researchers indicated that mcr-1 resistance may be more widely distributed than expected.

The L.A. County biorisk warning is the first public disclosure that the mcr-1 gene “has been reported in human specimens from five additional states and in animal specimens from two states.”