Good news: Salmonella Typhimurium and Heidelberg illnesses down which mirrors decrease in positives in chicken and a decreased incidence of hemolytic uremic syndrome from 2006 to 2016 which mirrors an STEC O157 decline in ground beef over the same timeframe.
A team from the US Centers for Disease Control and Prevention (CDC) and partners in 10 states that are part of the FoodNet surveillance network reported its findings today in the latest issue of Morbidity and Mortality Weekly Report (MMWR).
The group publishes an annual FoodNet report in early spring, and this year’s report sums up lab-confirmed infections from nine pathogens for 2017, detailing changes since 2006. The pathogens are Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, Shiga toxin-producing E coli (STEC), Shigella, Vibrio, and Yersinia.
For 2017, the FoodNet system identified 24,484 foodborne illnesses, 5,677 hospitalizations, and 122 deaths. Highest incidences per 100,000 population were for Campylobacter, Salmonella, and Shigella.
Growing use of culture-independent diagnostic tests (CIDTs) at public health labs is a useful tool for quickly identifying illnesses that might be missed by other lab tests, leading to more accurate incidence estimates, the authors write. They note, however, that their use can complicate the interpretation of estimates and that culturing isolates is still needed to reveal subtype information and test for antimicrobial susceptibility.
Regarding the infections only found on CIDT testing, percentages were highest for Yersinia (51%), Campylobacter (36%), Shigella (31%), Vibrio (29%), STEC (27%), Salmonella (9%), and Listeria (1%). Compared with findings from 2014 to 2016, incidence for 2017 was significantly higher for Cyclospora, Yersinia, Vibrio, STEC, Listeria, and Campylobacter.
Given that the use of CIDT panels are rising, tests more often routinely detect Cyclospora, Yersinia, Vibrio, and non-O157 STEC, the group said. “The increased incidence of these infections in 2017 was most likely driven by the increased use of CIDTs,” they wrote.
Of subtyped Salmonella isolates in 2017, the five most common were Enteritidis, Typhimurium, Newport, Javiana, and I 4,,12:i:-, a variant of Typhimurium. For 2017, the incidence of Heidelberg was 65% lower than from 2006 to 2008, with a similar decrease for Typhimurium over the same period.
When the scientists looked at STEC isolates, they found that the incidence of non-O157 STEC increased significantly in 2017 compared with 2014 to 2016. Though O157 STEC held steady, the incidence decreased 35% compared with 2006 to 2008.