The National Antimicrobial Resistance Monitoring System (NARMS) is a collaboration among state and local public health departments, the Center for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture (USDA). This national surveillance system has tracked trends in the antimicrobial resistance of certain bacteria found in people, retail meats, and food animals in the United States since 1996. The most recent NARMS report, released this week, indicated that multi-drug resistant Salmonella decreased during the past 10 years and resistance to two important groups of drugs – cephalosporins and fluoroquinolones – remained low in 2012.
About 1 in 5 Salmonella Heidelberg infections was resistant to ceftriaxone, a cephalapsorin drug. Ceftriaxone resistance is a problem because it makes severe Salmonella infections harder to treat, especially in children, according to the NARMS report. It is important to note that FDA prohibited certain unapproved uses of cephalosporins in poultry in April 2012.
Among the other findings in the 2012 report:
- Campylobacter resistance to ciprofloxacin remained at 25 percent, despite FDA’s 2005 withdrawal of its approval for the use of enrofloxacin in poultry. Ciprofloxacin and enrofloxacin are both in the fluoroquinolone class of drugs.
- Shigella resistance to ciprofloxacin (2 percent) and azithromycin (4 percent) is growing. However, no Shigella strains were resistant to both drugs.
- Although fluoroquinolone resistance remained low in 2012, Salmonella Enteritidis – the most common Salmonella type – accounted for 50 percent of infections resistant to the fluoroquinolone drug nalidixic acid, which is used in laboratory testing for resistance. Resistance to nalidixic acid relates to decreased susceptibility to ciprofloxacin, a widely used fluoroquinolone drug. Other work shows that many of the nalidixic acid resistant Salmonella Enteritidis infections are acquired during travel abroad.
The full 2012 NARMS report is available on the CDC website at www.cdc.gov/narms/reports/annual-human-isolates-report-2012.html.
