Animal & Veterinary

FDA Releases 2014 NARMS Integrated Report; Finds Measurable Improvements in Antimicrobial Resistance Levels

November 18, 2016

The U.S. Food and Drug Administration has released its 2014 National Antimicrobial Resistance Monitoring System (NARMS) Integrated Report, highlighting antimicrobial resistance patterns in bacteria isolated from humans, retail meats, and animals at slaughter. Specifically, the report focuses on major foodborne bacteria that are resistant to antibiotics that are considered important to human medicine, and on multidrug resistant organisms (described as resistant to three or more classes of antibiotics).

NARMS was established in 1996 as a partnership between the FDA, the Centers for Disease Control and Prevention, and the U.S. Department of Agriculture to track antibiotic resistance in foodborne bacteria. NARMS is critically important for monitoring trends in antimicrobial resistance among foodborne bacteria collected from humans, retail meats and food-producing animals. In particular, it assists the FDA in making data-driven decisions on the approval of safe and effective antimicrobial drugs for animals. NARMS will also be critical in evaluating the effectiveness of FDA’s Guidance for Industry #213 and the agricultural objectives in the Administration’s National Action Plan for Combating Antibiotic-Resistant Bacteria.

NARMS monitors foodborne bacteria to determine whether they are resistant to various antibiotics used in human and veterinary medicine. Specifically NARMS screens:

  • non-typhoidal Salmonella
  • Campylobacter
  • Escherichia coli
  • Enterococcus

Salmonella and Campylobacter are the leading bacterial causes of foodborne illness. While E. coli and Enterococcus may cause foodborne illness, they are included in NARMS mainly to help track the occurrence and spread of resistance.

Consumers can help protect themselves from foodborne bacteria, including antibiotic-resistant bacteria, by following four basic food safety tips: clean, separate, cook, chill. Learn more at http://www.foodsafety.gov/keep/basics/.

What’s New?

New Interactive Data Displays: To accompany the NARMS Integrated Reports, the FDA has published online enhanced interactive data displays and the bacterial isolate-level data. The enhanced interactive data displays allow users to explore trends in resistance to antimicrobial agents by host, sample type, bacterial species, and serotype. Users are also able to visualize the prevalence of Salmonella resistance genes by source. The isolate level database, which was originally published in August 2015, contains the entire collection of NARMS enteric bacterial isolates tested and shows data for Salmonella, Campylobacter, E. coli, and Enterococcus. For this report, the database has been updated with information on Salmonella resistance genes and gene mutations associated with resistance.

Whole Genome Sequence (WGS) Data: Whole genome sequencing provides the complete DNA sequence of a bacterial genome, allowing detailed genetic comparison of strains from humans with those from other sources. Studies show that the presence of known resistance determinants is highly correlated with clinical resistance.

Salmonella WGS data from all three components of the NARMS program accompany the 2014 NARMS Integrated Report. For Salmonella from human infections, all isolates exhibiting resistance to any antimicrobial drug were subject to WGS. For Salmonella-positive retail meat samples and carcass samples (cecal), WGS was performed on every isolate recovered in 2014. In addition, the WGS has been determined for historical Salmonella (over 4,500 isolates) recovered from retail meat sources since testing began in 2002. The genomes have been uploaded to the public database at the National Center for Biotechnology Information (NCBI). As these data accumulate, NARMS reports will evolve to incorporate temporal changes in the resistome along with the susceptibility information.

Findings

The points listed below summarize important observations from the 2014 NARMS Integrated Report. There are few changes from the 2012-2013 NARMS Integrated Report. Overall resistance continues to remain low for most human infections and there have been measurable improvements in resistance levels in some important areas.

Right Direction:
  1. The prevalence of Salmonella in both retail chicken meat (9.1 percent) and retail ground turkey (5.5 percent) was at its lowest level since retail meat testing began in 2002. The prevalence of Campylobacter in retail chicken meat samples has gradually declined over time to 33 percent, the lowest level since testing began.
  2. Approximately 80 percent of human Salmonella isolates are not resistant to any of the tested antibiotics. This has remained relatively stable over the past ten years. Resistance for three critically-important drugs (ceftriaxone, azithromycin, and ciprofloxacin) in human non-typhoidal Salmonella isolates remained below 3 percent.
  3. Overall, ceftriaxone resistance continued to decline in non-typhoidal Salmonella from all NARMS sources with the exception of retail turkey meat isolates, where it rose slightly. This was paralleled by a decline in ceftriaxone-resistant E. coli from retail chicken meat (from 13 percent in 2011 to 6.6 percent in 2014). In cattle, Salmonella isolates from carcasses collected at processing plants as part of Pathogen Reduction/Hazard Analysis Critical Control Point (PR/HACCP) testing, ceftriaxone resistance reached its lowest level (7.6 percent) since 1999. In 2014, ceftriaxone resistance in human Salmonella Heidelberg isolates was 8.5 percent, down from a peak of 24 percent in 2010.
  4. Among all Salmonella serotypes, the percentage of human isolates resistant to at least ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracyclines (ACSSuT) continued a steady decline to 3.1 percent, the lowest since testing began in 1996 (8.7 percent). Similarly, ACSSuT resistance in cattle PR/HACCP Salmonella typhimurium isolates declined sharply from 67 percent in 2009 to 7 percent in 2014, the lowest level since this testing began in 1997.
  5. With the exception of five isolates in the past ten years, no resistance has been detected in Enterococcus bacteria isolates to three important drugs: daptomycin, linezolid, and vancomycin.

While a majority of the observations in the 2014 NARMS Integrated Report show desirable trends, there are a few findings of potential concern.

Still of Concern:
  1. Decreased susceptibility to ciprofloxacin has increased in human and cattle (PR/HACCP) Salmonella serotype Dublin isolates since 2003, with slight declines since 2012. While the incidence of human Salmonella Dublin infections is relatively low, it can cause invasive disease with more severe outcomes, and ranks among the top four serotypes isolated from retail ground beef and cattle PR/HACCP samples.
  2. MDR Salmonella from turkey PR/HACCP samples has increased from approximately 27 percent to 41 percent over the past ten years.
  3. High and increasing levels of ciprofloxacin resistance were detected in Campylobacter jejuni from human (26.7 percent) and chicken PR/HACCP samples (28 percent) in 2014, and remained above 35 percent in Campylobacter coli from humans.
Note:

The NARMS Integrated report covers a time period before the full implementation of FDA's Guidance for Industry #213. The guidance announced a specific strategy for animal drug companies to voluntarily revise the labeling of their medically important antimicrobials used in the feed and water of food-producing animals to withdraw approved production uses and place the remaining therapeutic uses of these products under veterinary oversight. The affected animal drug companies have agreed to implement this strategy by the end of December 2016. 

Additional Resources

Contact FDA

240-402-7002
240-276-9115 FAX
Issued by: FDA, Center for Veterinary Medicine

7500 Standish Place, HFV-1

Rockville, MD 20855

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