CDC Identifies Germs Responsible for Majority of Food-Borne Illnesses in 2016

With recalls and outbreaks buzzing in news headlines so frequently, it is no a surprise that food-borne illnesses remain a significant public health concern in the United States. Although diagnosis of these infections and response time to control outbreaks has improved, more work still needs to be done to prevent these illnesses from happening in the first place.

In the Center for Disease Control and Prevention (CDC)’s most recent Morbidity and Mortality Report (MMWR), the public is offered a glimpse of preliminary data pertaining to food-borne illnesses in 2016—where we were, what’s working, where the gaps in information are, and what’s being done to make the country’s food supply safer.

The CDC’s Foodborne Diseases Active Surveillance Network, commonly referred to as FoodNet, collected data from 15% of the US population, and that information is shared in the FoodNet report in the MMWR, providing the public with the “most up-to-date information about food-borne illnesses” in the country. In 2016, FoodNet sites reported a staggering 24,029 food-borne infections, 5,512 related hospitalizations, and 98 related deaths.

Which germs caused the most illness last year?

According to the preliminary data, Campylobacter (which was responsible for 8,547 infections) and Salmonella (8,172 infections) made the top of the list. Other germs that made the list were: Shigella (2,913 infections), Shiga toxin-producing Escherichia coli (1,845 infections), Cryptosporidium (1,816 infections), Yersinia (302 infections), Vibrio (252 infections), Listeria (127 infections), and Cyclospora (55 infections).

Even though overall, Salmonella infections were high, compared with the average infections for 2013-2015, Salmonella Typhimurium infections decreased by 18%. The CDC postulates that regulatory action taken to “reduce Salmonella contamination in poultry and vaccination of chicken flocks by producers” might be responsible for the decrease.

In contrast, 2016 saw an increase in other infections, such as Yersinia, Cryptosporidium, and Shiga toxin-producing E. coli. The CDC suggests that this might not be a “true increase in illness,” however. Rather, the increase could be due to “newly-available” rapid diagnostic tests that make it significantly easier to diagnose such infections.

In fact, the CDC notes that this is the first time that food-borne infections diagnosed using only rapid diagnostic tests have been included in the total number of cases in FoodNet sites. In the past, only food-borne infections that had been confirmed by “traditional culture-based methods” were included in the total number of cases.

The data shows that testing techniques are shifting; rapid tests, or culture-independent diagnostic tests (CIDTs) are being used more frequently. This may be due to the fact that these tests can provide a fast diagnosis, which can lead to faster treatment. However, the tests do not provide detailed data on whether the pathogen is resistant to antibiotics or if it is a part of a larger, growing outbreak. CDC researchers point out that using these tests, without following up with cultures can result in an information gap.

“We need food-borne illness trend data to monitor progress toward making our food supply safer,” Robert Tauxe, MD, MPH, director of CDC’s Division of Foodborne, Waterborne, and Environmental Diseases said in a press release. “It’s important that laboratories continue to do follow-up cultures on CIDT-positive patients so public health officials can get the information needed to protect people from food-borne illness.”

CIDTs make infections “more visible” but it makes it harder for officials to monitor trends in food-borne illnesses because “the changes in the number of new infections could reflect changes in testing practices rather than a true increase in infections.” Therefore, comparing trends in 2016 data with data from previous years might be inaccurate. The CDC shared that FoodNet is already working on a solution for a way to continue to accurately track “needed progress toward” cutting down on these infections through the development of new tools.

Overall, although advancements have been made when it comes to diagnosis and response to these outbreaks, the true way to “win” this battle, lies in stronger prevention strategies.

“We are making progress in detecting and responding more quickly to food-borne illness, but our priority remains preventing illnesses from happening in the first place,” Susan Mayne, PhD, FACE, director of FDA’s Center for Food Safety and Applied Nutrition, shared in the press release. “The final rules we are implementing under the FDA Food Safety Modernization Act focus on prevention, and we will continue to work closely with other government agencies at the local, state, and federal levels, as well as our tribal and territorial partners, to support industry compliance with the new requirements.”

Steps are already being taken towards better food-borne illness prevention. The new performance standards for cutting down on the “harmful bacteria in chicken parts and ground poultry” coming from the US Department of Agriculture’s Food Safety and Inspection Service is one such example of the progress being made. In fact, these actions are estimated to result in the prevention of a whopping 50,000 illnesses caused by Salmonella and Campylobacter from contaminated chicken or turkey products each year.

The American public wants to know that the food they is consuming is safe and that it won’t make them ill. Arguably, the American food supply is one of the safest in the world and with this new data from the CDC and new advancements being made every day, we are one step closer to ensuring it stays that way.