The colistin-resistant strain of E.coli bacteria was discovered last month in the urine of a US patient, according to the report published on Thursday in the Antimicrobial Agents and Chemotherapy journal.
Colistin is one of the last-line antibiotics for the treatment of life-threatening infections. The emergence of a bug that cannot be killed by antibiotics could make common infections or routine surgeries deadly.
The Centers for Disease Control and Prevention (CDC) has warned that an "alarming rise" in the number of antibiotic-resistant bacteria had led to an increase in patient mortality. It said the problem has become aggravated by the absence of new antibiotics close to regulatory approval.