Abstract Background FoodNet conducts active laboratory-based surveillance for 9 pathogens transmitted commonly through food, including Shiga toxin-producing E. coli (STEC). Adoption of CIDTs has allowed for rapid identification of Shiga toxin or Shiga toxin genes, but incorporating multiple test results with differing sensitivity and specificity complicates treatment decisions and public health surveillance. Between 2007 and 2017, FoodNet reported increases in the use of CIDTs and decreases in rates of confirmation by culture. Methods We examined STEC cases reported to FoodNet during 2012−2017 with a positive immunoassay (IA) or polymerase chain reaction (PCR) test performed at a clinical laboratory, followed by positive or negative test at a state public health laboratory. Three test type combinations were assessed (IA/IA, PCR/PCR, and IA/PCR) by state, symptoms, test discordance, and culture (cx) result. Results During 2012−2017, 8,298 (76% of all STEC reported) specimens were tested by IA or PCR at both a clinical and a public health laboratory, 58% by IA/PCR, 27% by IA/IA, and 25% by PCR/PCR; some specimens had more than one test at each laboratory. Among these, 8,132 (98%) were also tested by cx. Among the IA/PCR test results, 20% were discordant and 75% of these were cx-negative. Even more of IA/IA (27%) and PCR/PCR (24%) results were discordant, and 75% of these were cx-negative. A median of 24% of test results were discordant (range by state, 13%–44%). Persons with discordant test results were less likely to have diarrhea (91% vs. 97%) and bloody diarrhea (33% vs. 57%). During 2012–2017, discordant results increased for IA/PCR (14% to 22%), IA/IA (17% to 34%), and PCR/PCR (6% to 25%). Most (85%) specimens with discordant results were cx-negative and 8% did not have a cx. Conclusion Almost a quarter of results were discordant, with marked variation by state, and most of these infections could not be confirmed by culture at the public health laboratory. Discordant results can pose problems for patient management. Including or excluding patients with discordant results also affects our ability to measure trends. Sensitivity and specificity of test types, test targets, and specimen transport must be considered when interpreting test results. Disclosures All authors: No reported disclosures.

Each year in the United States, ∼260,000 people get sick from contaminated fish. Fish is also the most commonly implicated food category in outbreaks. We reviewed the Centers for Disease Control and Prevention Foodborne Disease Outbreak Surveillance System for outbreaks resulting from consumption of fish during the period 1998-2015. We found 857 outbreaks associated with fish, resulting in 4815 illnesses, 359 hospitalizations, and 4 deaths. The median number of illnesses per outbreak was three (range: 2-425). The annual number of fish-associated outbreaks declined from an average of 62 per year during the period 1998-2006 to 34 per year during the period 2007-2015. Hawaii (221 outbreaks [26%]) and Florida (203 [24%]) reported the most outbreaks. Among 637 outbreaks (74%) with a confirmed etiology, scombrotoxin (349 [55%]) and ciguatoxin (227 [36%]) were by far most common. Most outbreak-associated illnesses were caused by scombrotoxin (1299 [34%]), Salmonella (978 [26%]), and ciguatoxin (894 [23%]). Most hospitalizations were caused by Salmonella (97 [31%]) and ciguatoxin (96 [31%]). Norovirus (105 average illnesses; range: [6-380]) and Salmonella (54 [3-425]) caused the largest outbreaks. Fish types implicated most often were tuna (37%), mahi-mahi (10%), and grouper (9%). The etiology-fish pairs responsible for the most outbreaks were scombrotoxin and tuna (223 outbreaks), scombrotoxin and mahi-mahi (64), and ciguatoxin and grouper (54). The pairs responsible for the most illnesses were scombrotoxin and tuna (720 illnesses) and Salmonella and tuna (660). Of the 840 outbreaks (98%) with a single location of food preparation, 52% were associated with fish prepared in a restaurant and 33% with fish prepared in a private home. Upstream control measures targeted to the most common etiologies and controls during processing and preparation could further reduce outbreaks caused by fish.

Post-diarrheal, pediatric hemolytic uremic syndrome (D+HUS) is a sequela of Shiga toxin-producing Escherichia coli (STEC) infection and is a common cause of acute kidney failure among US children. The Foodborne Diseases Active Surveillance Network (FoodNet) conducts surveillance in ten sites for physician-diagnosed D+HUS through a network of nephrologists and hospital discharge data review to estimate illness and corroborate STEC surveillance trends. The incidence of pediatric STEC overall in FoodNet sites has increased 18% from 2006 to 2014 while the incidence in STEC O157 has decreased by 28%. We summarized data on D+HUS cases, defined as HUS in children <18 years, reported to FoodNet during 2006–2014. We examined changes in incidence rates using US census data. Population density was defined by the United States Department of Agriculture Rural-Urban continuum codes. During 2006–2014, 719 D+HUS patients were reported, resulting in 13 (1.8%) deaths. The average annual incidence was 0.72 cases/100,000 children which varied by site (range: 0.39–1.28). Incidence was 5-fold greater among patients aged 1–3 years (2.34) than in other age groups (0.44). Incidence rates/100,000 children (IR) were highest among females (0.81) and non-Hispanics (0.70). IRs were higher in rural counties (1.15) than in urban counties (0.64). Comparing 2006–2008 with 2012–2014, average incidence decreased by 19%, from 0.81 to 0.66, with the greatest decreases found in children aged 1–3 years (35%, P = 0.04). No laboratory testing was performed for 10 (1%) cases. The proportion of cases with laboratory evidence of STEC infection increased 15 percentage points, from 69% in 2006–2008 to 84% in 2012–2014. In total, 537 (75%) D+HUS patients had laboratory evidence of STEC infection, 432 (80%) were culture-confirmed; the most common serogroups were O157 (94%), O111 (1.4%) and O121 (1.2%). During 2006–2014 cases of D+HUS decreased and showed marked demographic and geographic differences. The increased number of D+HUS cases with laboratory evidence of STEC is likely in part due to improvements in testing and adherence to guidelines. Prevention strategies for STEC and D+HUS should focus on young children, particularly in rural areas. All authors: No reported disclosures.

Salmonella enterica serotype Dublin is a cattle-adapted bacterium that typically causes bloodstream infections in humans. To summarize demographic, clinical, and antimicrobial drug resistance characteristics of human infections with this organism in the United States, we analyzed data for 1968-2013 from 5 US surveillance systems. During this period, the incidence rate for infection with Salmonella Dublin increased more than that for infection with other Salmonella. Data from 1 system (FoodNet) showed that a higher percentage of persons with Salmonella Dublin infection were hospitalized and died during 2005-2013 (78% hospitalized, 4.2% died) than during 1996-2004 (68% hospitalized, 2.7% died). Susceptibility data showed that a higher percentage of isolates were resistant to > 7 classes of antimicrobial drugs during 2005-2013 (50.8%) than during 1996-2004 (2.4%)

BACKGROUND:Campylobacteriosis, a leading cause of foodborne illness in the United States, was not nationally notifiable until 2015. Data describing national patterns and trends are limited. We describe the epidemiology of Campylobacter infections in the United States during 2004-2012.METHODS:We summarized laboratory-confirmed campylobacteriosis data from the Nationally Notifiable Disease Surveillance System, National Outbreak Reporting System, National Antimicrobial Resistance Monitoring System, and Foodborne Diseases Active Surveillance Network.RESULTS:During 2004-2012, 303520 culture-confirmed campylobacteriosis cases were reported. Average annual incidence rate (IR) was 11.4 cases/100000 persons, with substantial variation by state (range, 3.1-47.6 cases/100000 persons). IRs among patients aged 0-4 years were more than double overall IRs. IRs were highest among males in all age groups. IRs in western states and rural counties were higher (16.2/100000 and 14.2/100000, respectively) than southern states and metropolitan counties (6.8/100000 and 11.0/100000, respectively). Annual IRs increased 21% from 10.5/100000 during 2004-2006 to 12.7/100000 during 2010-2012, with the greatest increases among persons aged >60 years (40%) and in southern states (32%). The annual median number of Campylobacter outbreaks increased from 28 in 2004-2006 to 56 in 2010-2012; in total, 347 were reported. Antimicrobial susceptibility testing of isolates from 4793 domestic and 1070 travel-associated infections revealed that, comparing 2004-2009 to 2010-2012, ciprofloxacin resistance increased among domestic infections (12.8% vs 16.1%).CONCLUSIONS:During 2004-2012, incidence of campylobacteriosis, outbreaks, and clinically significant antimicrobial resistance increased. Marked demographic and geographic differences exist. Our findings underscore the importance of national surveillance and understanding of risk factors to guide and target control measures.