August 11, 2015
The U.S. Food and Drug Administration has released its 2012-2013 National Antimicrobial Resistance Monitoring System (NARMS) Integrated Report. This report replaces FDA’s annual NARMS Executive Summary report and highlights antimicrobial resistance patterns in bacteria isolated from humans, retail meats, and animals at slaughter. Specifically, the report focuses on major foodborne pathogens that are resistant to antibiotics that are considered important to human medicine, and on multidrug resistant pathogens (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 pathogens to determine whether they are resistant to various antibiotics used in human and veterinary medicine. Specifically NARMS screens:
- non-typhoidal Salmonella
- Escherichia coli
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/.
Changes in methodology:
- The integrated report reflects improvements in NARMS testing. Animal testing now includes cecal (intestinal) testing of food-producing animals presented for slaughter before they are exposed to in-plant processing, making them better indicators of the microbial status of animals in farm settings. Additionally, the new in-plant sampling makes it possible to distinguish market hogs and sows among swine samples and dairy and beef among cattle samples.
- NARMS is also now using epidemiological cut-off values to interpret antimicrobial susceptibility data in a move toward globally harmonized methods for Campylobacter surveillance.
- Finally, NARMS has updated its measurement for cefepime, an antimicrobial that is used to screen for extended-spectrum beta-lactamase (ESBL) production, to reflect changes made to international testing best practices by the Clinical and Laboratory Standards Institute.
Changes in reporting:
Unlike previous year’s reports, the NARMS integrated report covers multiple years (2012-2013) and has a new format to help better communicate the complex information presented. The tables and graphs used to summarize collected data in previous reports are still available. However they are enhanced by new interactive graphs designed to help the reader quickly visualize the latest antimicrobial resistance trends. Specifically, this report includes ten interactive graphs that allow users to visualize antimicrobial resistance among Salmonella and Campylobacter in humans, retail meats and food animals by year from the date of initial testing through 2013. The visual information is strengthened by a more descriptive narrative summary that highlights the most important findings and provides a list of key points from the most recent data.
Overall, the 2012 & 2013 Integrated Report reveals mostly encouraging findings, with some areas of concern.
- About 80% of human Salmonella isolates are not resistant to any of the tested antibiotics, a finding that has not changed in the past 10 years. Further, resistance to ceftriaxone, azithromycin, and quinolones, three important drugs used to treat human Salmonella isolates, remains below 3%.
- Salmonella multi-drug resistance (resistance to three or more classes of antibiotics) in human, cattle, and chicken isolates has not changed (~10%) in the last decade, and the numbers of multi-drug resistant Salmonella isolates in retail chicken have gone down (~3%).
- Campylobacter jejuni resistance to the fluoroquinolone ciprofloxacin, the most common antibiotic used to treat human C. jejuni illness, was at its lowest level in retail chicken to date (11%). Campylobacter jejuni causes most human Campylobacter infections.
Still of Concern:
- Multidrug resistance (MDR) in human isolates of a common Salmonella serotype (l 4,,12:i:-) continues to rise. Resistance has more than doubled from 18% in 2011 to 46% in 2013.
- An increase in MDR and ceftriaxone resistance was also observed in Salmonella serotype Dublin isolated from cattle and human sources.
The NARMS Integrated report covers time periods before the FDA's publication in December 2013 of 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 December 2016.