Case report of transient mcr-1-haboring Escherichia coli with concurrent Staphylococcus aureus bacteremia in Long Beach, California

A 55-year-old man with history of chronic hepatitis B cirrhosis presented to an emergency department in California with abdominal pain, constipation, and jaundice. The patient developed methicillin-susceptible S. aureus bacteremia with a concurrent transient E. coli. This organism carried mcr-1 in a plasmid similar to other mcr-1-carrying plasmids from the USA. The spread of mcr-1 into carbapenem-resistant isolates is of great concern and monitoring of this resistance mechanism is important.