The U.S. Food and Drug Administration this week released the findings of its National Antimicrobial Resistance Monitoring System Integrated Report, updated with 2012-2013 data.
The 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, FDA said the report focuses on major foodborne pathogens that are resistant to antibiotics that are considered important to human medicine, and on "multidrug resistant" pathogens, or those 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 USDA to track antibiotic resistance in foodborne bacteria. It helps FDA make decisions on the approval of safe and effective antimicrobial drugs for animals, and will be critical in evaluating the effectiveness of Guidance 213.
Guidance 213 asks 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.
NARMS monitors foodborne pathogens to determine whether they are resistant to various antibiotics used in human and veterinary medicine. Those pathogens include non-typhoidal Salmonella, Campylobacter, E. coli, and 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.
What the report found
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 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.
FDA said there are a few issues that are still of concern, however. According to the report, multidrug resistance 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.
FDA also found an increase in MDR and ceftriaxone resistance was in Salmonella serotype Dublin isolated from cattle and human sources.