This message is intended for all
health care providers, particularly hospital-based providers.
distribute as appropriate.
An mcr-1 producing
bacterial isolate has been identified in a Los Angeles County
(LAC) resident, the first reported case in California. The mcr-1
gene confers resistance to the antibiotic colistin, one of
few “last resort” antibiotics used to treat infections caused by
certain multi-drug resistant organisms.
Hospital-based providers should
follow LAC Department of Public Health (DPH) recommendations
regarding infection control, testing, and reporting for patients
with suspected and confirmed mcr-1 organisms.
County has identified the first patient in California with an mcr-1
producing bacterial isolate. The E. coli infection was most
likely acquired during international travel and no evidence of spread
in the local health care community has been identified. Mcr-1
producing bacteria were first identified in the United States in a
Pennsylvania patient in May 2016; since then, the mcr-1 gene
has been reported in human specimens from five additional states and
in animal specimens from two states. The appearance of mcr-1
in Los Angeles serves as a reminder of the importance of infection
control measures and antibiotic stewardship.
Requested of Providers
providers should follow Standard and Contact Precautions for any
patient who is suspected to be colonized or infected with mcr-1 positive
organisms based on colistin resistance, pending mcr-1 confirmation,
OR any patient confirmed to be colonized or infected with mcr-1
√ Laboratory Testing: Isolates
with a minimum inhibitory concentration (MIC) to colistin of 4 µg/ml
or higher should be tested for the presence of mcr-1. If
hospital mcr-1 confirmatory testing cannot be performed,
contact LAC DPH Acute Communicable Disease Control (ACDC) at
213-240-7941 to arrange for the isolates to be tested at the LAC
Public Health Laboratory.
All mcr-1 positive isolates identified in LAC residents
and at LAC health care facilities must be reported within one working
day by calling ACDC at 213-240-7941.
County DPHAcute Communicable Disease Control Program: •Weekdays 8:30am-5pm: call 213-240-7941 •After hours: call 213-974-1234 and ask for
the physician on call. For Residents of Long Beach and Pasadena:
Health and Human Services: •Weekdays 8am-5pm: call 562-570-4302 •After hours: call 562-435-6711 and ask for
Communicable Disease Officer.
Health Department: •Weekdays: call the Communicable Disease Control
Program 626-744-6089 •After hours: call 626-744-6043.