FDA cautions against EWG antibiotic-resistant bacteria findings

April 24, 2013

An analysis of the U.S. Food and Drug Administration’s (FDA) National Antimicrobial Resistance Monitoring System (NARMS) by the Environmental Working Group (EWG) has found high percentages of supermarket meat containing antibiotic-resistant bacteria. EWG’s analysis of data in the NARMS found that store-bought meat tested in 2011 contained antibiotic-resistant bacteria in 81% of raw ground turkey, 69% of raw pork chops, 55% of raw ground beef, and 39% of raw chicken parts.

EWG researchers found that 53% of raw chicken samples were tainted with an antibiotic-resistant form of Escherichia coli. As well, EWG found that antibiotic resistance in Salmonella is growing fast: of all Salmonella microbes found on raw chicken sampled in 2011, 74% were antibiotic-resistant, compared to less than 50% in 2002.

The FDA has responded, cautioning against misinterpretation of the data. The agency stated: “While FDA is always concerned when we see antimicrobial resistance, we believe the EWG report oversimplifies the NARMS data and provides misleading conclusions. We do not believe that EWG fully considered important factors that put these results in context.”

Some of these factors include:

  • Whether the bacterium is a foodborne pathogen. The report highlights resistance to Enterococcus, but this is not considered a foodborne pathogen. Instead, we include it because its behavior is helpful in understanding how resistance occurs.
  • Which drug(s) the bacterium is naturally resistant to. For example, most Enterococcus faecalis is naturally resistant to the antibiotic class of lincosamides. Because we know and expect to see this resistance, we are not as concerned with resistance in this species the way we would be with resistance in true pathogens like Salmonella and Campylobacter.
  • Why NARMS includes certain drugs in its testing design. We include some antibiotics for epidemiology purposes—to track the spread of certain bacteria or certain genes. But resistance to these antibiotics doesn’t reflect a danger to public health.
  • Whether the antibiotics that are commonly used to treat patients are still effective. NARMS data indicates that first-line treatments for all four bacteria that we track (Salmonella, Enterococcus, Escherichia coli,and Campylobacter) are still effective.
  • What the 2011 data indicate relative to similar data reported for prior years.

In addition, the FDA believes it is inaccurate and “alarmist” to define bacteria resistant to one, or even a few, antimicrobials as “superbugs” if these same bacteria are still treatable by other commonly used antibiotics.

EWG report

FDA release