Foodborne Diseases Active Surveillance Network Research Articles

Trends in Salmonella Infantis human illness incidence and chicken carcass prevalence in the United States; 1996-2019.

The incidence of human illness due to Salmonella Infantis reported to Foodborne Diseases Active Surveillance Network and the prevalence of Infantis on chicken carcasses reported by the United States Department of Agriculture Food Safety and Inspection Service have increased significantly in the past decade. However, the trends do not appear coincident, as would be expected if the increased prevalence in chicken led to the increase in the incidence of human illness. Salmonella Infantis incidence and prevalence trends are analyzed using penalized B-spline methods for generalized additive regression models. The association between the two time series is analyzed using time-lagged rank-order cross-correlation. Geographic variations in reported incidence and trends are also explored. The increase in human incidence of Salmonella Infantis began circa 2011. The increase in chicken carcass prevalence began circa 2015. A 4-year lag on chicken carcass prevalence maximizes the rank-order cross-correlation with the incidence of illness. While chicken consumption undoubtedly contributes to the incidence of human illness due to Salmonella Infantis, the initial increase in reported illness was likely due to one or more other transmission pathways. Other potential transmission pathways include non-chicken foodborne, waterborne, person-to-person, animal contact, and environmental.

Syndromic gastrointestinal panel diagnostic tests have changed our understanding of the epidemiology of Yersinia enterocolitica—Foodborne Diseases Active Surveillance Network, 2010–2021

Abstract Background In the United States, Yersinia enterocolitica causes a diarrheal disease historically associated with winter months and understood to predominantly occur among Black or African American infants and Asian children. Clinical laboratory adoption of culture-independent diagnostic tests (CIDTs), in place of culture methods has led to marked increases in diagnoses. Methods We describe laboratory-diagnosed infections caused by Y. enterocolitica in 10 state health departments of the Foodborne Diseases Active Surveillance Network. A counterfactual random forest model was used to identify individual, and community-level social determinants of health associated with the type of test used to detect Y. enterocolitica. Results Annual reported incidence of Y. enterocolitica infection increased from 0.3 per 100,000 in 2010 to 1.3 per 100,000 in 2021. The proportion of infections detected by CIDT increased from 3% in 2012 to 89% in 2021. Nearly all (97%) CIDT-positive infections were detected by commercially available syndromic gastrointestinal panel tests. Reported incidence increased for adults ≥18 years, regardless of race and ethnicity. Nearly half of infections occurred during May to September in 2016–2021. The probability of CIDT-detected infection increased with age and was greater for White compared with Asian persons. In addition to year, an ill person’s location of residence had a significant impact on odds of infection detection by CIDT versus culture method. Conclusions Improved detection due to increased use of CIDTs has altered our understanding of yersinosis epidemiology. Our findings suggest that yersinosis diagnosis quantitatively varies between demographic groups by diagnostic method and that differential access to CIDTs may still affect our understanding of yersinosis epidemiology.

Clinical Outcomes of Patients With Nontyphoidal Salmonella Infections by Isolate Resistance-Foodborne Diseases Active Surveillance Network, 10 US Sites, 2004-2018.

Nontyphoidal Salmonella causes an estimated 1.35 million US infections annually. Antimicrobial-resistant strains are a serious public health threat. We examined the association between resistance and the clinical outcomes of hospitalization, length-of-stay ≥3 days, and death. We linked epidemiologic data from the Foodborne Diseases Active Surveillance Network with antimicrobial resistance data from the National Antimicrobial Resistance Monitoring System (NARMS) for nontyphoidal Salmonella infections from 2004 to 2018. We defined any resistance as resistance to ≥1 antimicrobial and clinical resistance as resistance to ampicillin, azithromycin, ceftriaxone, ciprofloxacin, or trimethoprim-sulfamethoxazole (for the subset of isolates tested for all 5 agents). We compared outcomes before and after adjusting for age, state, race/ethnicity, international travel, outbreak association, and isolate serotype and source. Twenty percent of isolates (1105/5549) had any resistance, and 16% (469/2969) had clinical resistance. Persons whose isolates had any resistance were more likely to be hospitalized (31% vs 28%, P = .01) or have length-of-stay ≥3 days (20% vs 16%, P = .01). Deaths were rare but more common among those with any than no resistance (1.0% vs 0.4%, P = .01). Outcomes for patients whose isolates had clinical resistance did not differ significantly from those with no resistance. After adjustment, any resistance (adjusted odds ratio 1.23, 95% confidence interval 1.04-1.46) remained significantly associated with hospitalization. We observed a significant association between nontyphoidal Salmonella infections caused by resistant pathogens and likelihood of hospitalization. Clinical resistance was not associated with poorer outcomes, suggesting that factors other than treatment failure (eg, strain virulence, strain source, host factors) may be important.

Modelling counterfactual incidence during the transition towards culture-independent diagnostic testing.

Culture-independent diagnostic testing (CIDT) provides rapid results to clinicians and is quickly displacing traditional detection methods. Increased CIDT use and sensitivity likely result in higher case detection but might also obscure infection trends. Severe illness outcomes, such as hospitalization and death, are likely less affected by changes in testing practices and can be used as indicators of the expected case incidence trend had testing methods not changed. Using US Foodborne Diseases Active Surveillance Network data during 1996-2019 and mixed effects quasi-Poisson regression, we estimated the expected yearly incidence for nine enteric pathogens. Removing the effect of CIDT use, CIDT panel testing and culture-confirmation of CIDT testing, the modelled incidence in all but three pathogens (Salmonella, Shigella, STEC O157) was significantly lower than the observed and the upward trend in Campylobacter was reversed from an observed 2.8% yearly increase to a modelled -2.8% yearly decrease (95% credible interval: -4.0, -1.4). Severe outcomes may be useful indicators in evaluating trends in surveillance systems that have undergone a marked change.

Epidemiology and Antimicrobial Resistance of Campylobacter Infections in the United States, 2005-2018.

Campylobacter is the most common cause of bacterial diarrhea in the United States; resistance to macrolides and fluoroquinolones limits treatment options. We examined the epidemiology of US Campylobacter infections and changes in resistance over time. The Foodborne Diseases Active Surveillance Network receives information on laboratory-confirmed Campylobacter cases from 10 US sites, and the National Antimicrobial Resistance Monitoring System receives a subset of isolates from these cases for antimicrobial susceptibility testing. We estimated trends in incidence of Campylobacter infection, adjusting for sex, age, and surveillance changes attributable to culture-independent diagnostic tests. We compared percentages of isolates resistant to erythromycin or ciprofloxacin during 2005-2016 with 2017-2018 and used multivariable logistic regression to examine the association of international travel with resistance. Adjusted Campylobacter incidence remained stable or decreased for all groups analyzed since 2012. Among 2449 linked records in 2017-2018, the median patient age was 40.2 years (interquartile range, 21.6-57.8 years), 54.8% of patients were male, 17.2% were hospitalized, and 0.2% died. The percentage of resistant infections increased from 24.5% in 2005-2016 to 29.7% in 2017-2018 for ciprofloxacin (P < .001) and from 2.6% to 3.3% for erythromycin (P = .04). Persons with recent international travel had higher odds than nontravelers of having isolates resistant to ciprofloxacin (adjusted odds ratio [aOR] varied from 1.7 to 10.6 by race/ethnicity) and erythromycin (aOR = 1.7; 95% confidence interval, 1.3-2.1). Campylobacter incidence has remained stable or decreased, whereas resistance to antimicrobials recommended for treatment has increased. Recent international travel increased the risk of resistance.

Preliminary Incidence and Trends of Infections Caused by Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2022.

Each year, infections from major foodborne pathogens are responsible for an estimated 9.4 million illnesses, 56,000 hospitalizations, and 1,350 deaths in the United States (1). To evaluate progress toward prevention of enteric infections in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) conducts surveillance for laboratory-diagnosed infections caused by eight pathogens transmitted commonly through food at 10 U.S. sites. During 2020-2021, FoodNet detected decreases in many infections that were due to behavioral modifications, public health interventions, and changes in health care-seeking and testing practices during the COVID-19 pandemic. This report presents preliminary estimates of pathogen-specific annual incidences during 2022, compared with average annual incidences during 2016-2018, the reference period for the U.S. Department of Health and Human Services' Healthy People 2030 targets (2). Many pandemic interventions ended by 2022, resulting in a resumption of outbreaks, international travel, and other factors leading to enteric infections. During 2022, annual incidences of illnesses caused by the pathogens Campylobacter, Salmonella, Shigella, and Listeria were similar to average annual incidences during 2016-2018; however, incidences of Shiga toxin-producing Escherichia coli (STEC), Yersinia, Vibrio, and Cyclospora illnesses were higher. Increasing culture-independent diagnostic test (CIDT) usage likely contributed to increased detection by identifying infections that would have remained undetected before widespread CIDT usage. Reducing pathogen contamination during poultry slaughter and processing of leafy greens requires collaboration among food growers and processors, retail stores, restaurants, and regulators.

Trends in reported illness due to poultry- and nonpoultry associated Salmonella serotypes; United States 1996-2019.

Retrospective review is a key to designing effective food safety measures. Despite the reported reduction of Salmonella prevalence in poultry products, there has not been a concomitant reduction of the overall incidence of Salmonella illnesses reported to the US Foodborne Diseases Active Surveillance Network (FoodNet) since 1996. However, there have been significant annual trends among Salmonella serotypes. This analysis examines trends in the reported incidence of illness due to poultry- and nonpoultry associated Salmonella serotypes. Overall, the findings indicate declining trends in illness due to the poultry-associated serotypes and increasing trends in illness due to Salmonella serotypes not associated with poultry.

Antimicrobial-Resistant Nontyphoidal Salmonella Infection Following International Travel-United States, 2018-2019.

Antimicrobial resistance in nontyphoidal Salmonella (NTS) can limit treatment options. We assessed the contribution of international travel to antimicrobial-resistant NTS infections. We describe NTS infections that were reported to the Foodborne Diseases Active Surveillance Network during 2018-2019 and screened for genetic resistance determinants, including those conferring decreased susceptibility to first-line agents (ciprofloxacin, ceftriaxone, or azithromycin). We used multivariable logistic regression to assess the association between resistance and international travel during the 7 days before illness began. We estimated the contribution of international travel to resistance using population-attributable fractions, and we examined reported antimicrobial use. Among 9301 NTS infections, 1159 (12%) occurred after recent international travel. Predicted resistance to first-line antimicrobials was more likely following travel; the adjusted odds ratio varied by travel region and was highest after travel to Asia (adjusted odds ratio, 7.2 [95% confidence interval, 5.5-9.5]). Overall, 19% (95% confidence interval, 17%-22%) of predicted resistance to first-line antimicrobials was attributable to international travel. More travelers than nontravelers receiving ciprofloxacin or other fluoroquinolones had isolates with predicted resistance to fluoroquinolones (29% vs 9%, respectively; P < .01). International travel is a substantial risk factor for antimicrobial-resistant NTS infections. Understanding risks of resistant infection could help target prevention efforts.

Socioeconomic impacts of COVID-19 pandemic on foodborne illnesses in the United States

Foodborne diseases continue to impact human health and the economy. The COVID-19 pandemic has dramatically affected the food system from production to consumption. This project aims to determine the impact of the COVID-19 pandemic on the spread of foodborne diseases and the factors that may have contributed, including environmental, behavioral, political, and socioeconomic. Data for this study were collected from The Foodborne Diseases Active Surveillance Network (FoodNet) for 2015-2020. FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut (CT), Georgia (GA), Maryland (MD), Minnesota (MN), New Mexico (NM), Oregon (OR), Tennessee (TN), and selected counties in California (CA), Colorado (CO), and New York (NY). Data were analyzed using SAS to determine the changes in rates of foodborne pathogens reported in FoodNet before and during the COVID-19 pandemic in the ten reporting states. Results of the study showed a significant decline in the incidences of foodborne diseases ranging between 25% and 60%. A geographical variation was also observed between California and states with the highest decline rate of foodborne illnesses. Policies and restrictions, in addition to environmental and behavioral changes during the COVID-19 pandemic, may have reduced rates of foodborne diseases.

Preliminary Incidence and Trends of Infections Caused by Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2016-2021.

To evaluate progress toward prevention of enteric infections in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) conducts active population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cyclospora, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC), Shigella, Vibrio, and Yersinia at 10 U.S. sites. This report summarizes preliminary 2021 data and describes changes in annual incidence compared with the average annual incidence for 2016-2018, the reference period for the U.S. Department of Health and Human Services' (HHS) Healthy People 2030 goals for some pathogens (1). During 2021, the incidence of infections caused by Salmonella decreased, incidence of infections caused by Cyclospora, Yersinia, and Vibrio increased, and incidence of infections caused by other pathogens did not change. As in 2020, behavioral modifications and public health interventions implemented to control the COVID-19 pandemic might have decreased transmission of enteric infections (2). Other factors (e.g., increased use of telemedicine and continued increase in use of culture-independent diagnostic tests [CIDTs]) might have altered their detection or reporting (2). Much work remains to achieve HHS Healthy People 2030 goals, particularly for Salmonella infections, which are frequently attributed to poultry products and produce, and Campylobacter infections, which are frequently attributed to chicken products (3).

Changing Diagnostic Testing Practices for Foodborne Pathogens, Foodborne Diseases Active Surveillance Network, 2012-2019.

Pathogen detection has changed with increased use of culture-independent diagnostic tests (CIDTs). CIDTs do not yield isolates, which are necessary to detect outbreaks using whole-genome sequencing. The Foodborne Diseases Active Surveillance Network (FoodNet) monitors clinical laboratory testing practices to improve interpretation of surveillance data and assess availability of isolates. We describe changes in practices over 8 years. During 2012-2019, 10 FoodNet sites collected standardized data about practices in clinical laboratories (range, 664-723 laboratories) for select enteric pathogens. We assessed changes in practices. During 2012-2019, the percentage of laboratories that used only culture methods decreased, with the largest declines for Vibrio (99%-57%) and Yersinia (99%-60%). During 2019, the percentage of laboratories using only CIDTs was highest for Shiga toxin-producing Escherichia coli (43%), Campylobacter (34%), and Vibrio (34%). From 2015 to 2019, the percentage of laboratories that performed reflex culture after a positive CIDT decreased, with the largest declines for Shigella (75%-42%) and Salmonella (70%-38%). The percentage of laboratories that routinely submitted isolates to a public health laboratory decreased for all bacterial pathogens examined from 2015 to 2019. By increasing use of CIDTs and decreasing reflex culture, clinical laboratories have transferred the burden of isolate recovery to public health laboratories. Until technologies allow for molecular subtyping directly from a patient specimen, state public health laboratories should consider updating enteric disease reporting requirements to include submission of isolates or specimens. Public health laboratories need resources for isolate recovery.

1258. Antibiotic Resistant Nontyphoidal Salmonella Infection Following International Travel — United States, 2018

Abstract Background Antibiotic resistance in nontyphoidal Salmonella can limit treatment options for patients requiring antibiotic therapy. We assessed the contribution of international travel to resistance among nontyphoidal Salmonella infections. Methods We describe characteristics of nontyphoidal Salmonella infections in the Foodborne Diseases Active Surveillance Network during 2018 that were also reported to PulseNet and the National Antimicrobial Resistance Monitoring System. We defined genetic resistance to first-line antibiotics as the presence of genes or mutations known to confer decreased susceptibility or resistance to ciprofloxacin, azithromycin, or ceftriaxone. We used multivariable logistic regression to assess the association between resistance to first-line antibiotics and international travel in the 7 days before symptom onset overall and by United Nations statistical region, and we estimated the contribution of travel to resistance using population attributable fractions. Results Among 3,238 nontyphoidal Salmonella infections, 356 (11%) were in patients who traveled internationally in the 7 days before symptom onset. Of these, 109/356 (31%) had isolates with genetic resistance to first-line antibiotics, compared with 308/2882 (11%) non-travelers. Resistance was more likely following travel, after adjusting for age and sex (OR 3.7, 95% CI 2.9–4.8). Nine genes or mutations conferred resistance to first-line antibiotics among travel-associated isolates. The risk of resistance varied by region and was highest after travel to Asia (OR 7.5, 95% CI 4.7–12.0). Overall, 17.1% (95% CI 12.2%–21.7%) of genetic resistance to first-line antibiotics was attributable to international travel. Conclusion For patients with nontyphoidal Salmonella infections, international travel is associated with approximately three-fold increased risk that first-line agents could be ineffective. The estimated 17% of resistance to first-line antibiotics attributable to travel is encoded by relatively few genes and mutations. Investigation of the major sources of resistant strains could help target prevention efforts. Travel region should be considered when treating empirically; treatment should be adjusted based on results from antibiotic susceptibility testing. Disclosures All Authors: No reported disclosures

Decreased Incidence of Infections Caused by Pathogens Transmitted Commonly Through Food During the COVID-19 Pandemic - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2017-2020.

Foodborne illnesses are a substantial and largely preventable public health problem; before 2020 the incidence of most infections transmitted commonly through food had not declined for many years. To evaluate progress toward prevention of foodborne illnesses in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program monitors the incidence of laboratory-diagnosed infections caused by eight pathogens transmitted commonly through food reported by 10 U.S. sites.* FoodNet is a collaboration among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration. This report summarizes preliminary 2020 data and describes changes in incidence with those during 2017-2019. During 2020, observed incidences of infections caused by enteric pathogens decreased 26% compared with 2017-2019; infections associated with international travel decreased markedly. The extent to which these reductions reflect actual decreases in illness or decreases in case detection is unknown. On March 13, 2020, the United States declared a national emergency in response to the COVID-19 pandemic. After the declaration, state and local officials implemented stay-at-home orders, restaurant closures, school and child care center closures, and other public health interventions to slow the spread of SARS-CoV-2, the virus that causes COVID-19 (1). Federal travel restrictions were declared (1). These widespread interventions as well as other changes to daily life and hygiene behaviors, including increased handwashing, have likely changed exposures to foodborne pathogens. Other factors, such as changes in health care delivery, health care-seeking behaviors, and laboratory testing practices, might have decreased the detection of enteric infections. As the pandemic continues, surveillance of illness combined with data from other sources might help to elucidate the factors that led to the large changes in 2020; this understanding could lead to improved strategies to prevent illness. To reduce the incidence of these infections concerted efforts are needed, from farm to processing plant to restaurants and homes. Consumers can reduce their risk of foodborne illness by following safe food-handling and preparation recommendations.

Climate change, extreme events, and increased risk of salmonellosis: foodborne diseases active surveillance network (FoodNet), 2004-2014

BackgroundInfections with nontyphoidal Salmonella cause an estimated 19,336 hospitalizations each year in the United States. Sources of infection can vary by state and include animal and plant-based foods, as well as environmental reservoirs. Several studies have recognized the importance of increased ambient temperature and precipitation in the spread and persistence of Salmonella in soil and food. However, the impact of extreme weather events on Salmonella infection rates among the most prevalent serovars, has not been fully evaluated across distinct U.S. regions.MethodsTo address this knowledge gap, we obtained Salmonella case data for S. Enteriditis, S. Typhimurium, S. Newport, and S. Javiana (2004-2014; n = 32,951) from the Foodborne Diseases Active Surveillance Network (FoodNet), and weather data from the National Climatic Data Center (1960-2014). Extreme heat and precipitation events for the study period (2004-2014) were identified using location and calendar day specific 95th percentile thresholds derived using a 30-year baseline (1960-1989). Negative binomial generalized estimating equations were used to evaluate the association between exposure to extreme events and salmonellosis rates.ResultsWe observed that extreme heat exposure was associated with increased rates of infection with S. Newport in Maryland (Incidence Rate Ratio (IRR): 1.07, 95% Confidence Interval (CI): 1.01, 1.14), and Tennessee (IRR: 1.06, 95% CI: 1.04, 1.09), both FoodNet sites with high densities of animal feeding operations (e.g., broiler chickens and cattle). Extreme precipitation events were also associated with increased rates of S. Javiana infections, by 22% in Connecticut (IRR: 1.22, 95% CI: 1.10, 1.35) and by 5% in Georgia (IRR: 1.05, 95% CI: 1.01, 1.08), respectively. In addition, there was an 11% (IRR: 1.11, 95% CI: 1.04-1.18) increased rate of S. Newport infections in Maryland associated with extreme precipitation events.ConclusionsOverall, our study suggests a stronger association between extreme precipitation events, compared to extreme heat, and salmonellosis across multiple U.S. regions. In addition, the rates of infection with Salmonella serovars that persist in environmental or plant-based reservoirs, such as S. Javiana and S. Newport, appear to be of particular significance regarding increased heat and rainfall events.

Disparities in Incidence and Severity of Shigella Infections Among Children-Foodborne Diseases Active Surveillance Network (FoodNet), 2009-2018.

Shigella infections are an important cause of diarrhea in young children and can result in severe complications. Disparities in Shigella infections are well documented among US adults. Our objective was to characterize disparities in incidence and severity of Shigella infections among US children. We analyzed laboratory-diagnosed Shigella infections reported to FoodNet, an active, population-based surveillance system in 10 US sites, among children during 2009-2018. We calculated the incidence rate stratified by sex, age, race/ethnicity, Shigella species, and disease severity. Criteria for severe classification were hospitalization, bacteremia, or death. The odds of severe infection were calculated using logistic regression. During 2009-2018, 10 537 Shigella infections were reported in children and 1472 (14.0%) were severe. The incidence rate was 9.5 infections per 100 000 child-years and the incidence rate of severe infections was 1.3 per 100 000 child-years. Incidence was highest among children aged 1-4 years (19.5) and lowest among children aged 13-17 years (2.3); however, children aged 13-17 years had the greatest proportion of severe infections (21.2%). Incidence was highest among Black (16.2 total; 2.3 severe), Hispanic (13.1 total; 2.3 severe), and American Indian/Alaska Native (15.2 total; 2.5 severe) children. Infections caused by non-sonnei species had higher odds of severity than infections caused by Shigella sonnei (adjusted odds ratio 2.58; 95% confidence interval 2.12-3.14). The incidence and severity of Shigella infections among US children vary by age, race/ethnicity, and Shigella species, warranting investigation of unique risk factors among pediatric subpopulations.

Seasonal Associations Between Foodborne Campylobacter Infections and Ambient Temperature in US, 2010–2019

Abstract Objectives In order to effectively mitigate the effects of climate change on human health, spatiotemporal relationships between Campylobacter infections and environmental drivers have to be systematically examined to determine whether common seasonal summer peaks observed in Campylobacter infections are well aligned with peaks in raising ambient temperatures. This study aims to evaluate the seasonal relationship between monthly ambient temperature and the monthly Campylobacter infections routinely collected by the CDC Foodborne Diseases Active Surveillance Network (FoodNet) in the United States in 2010–2019. Methods We created time series of monthly Campylobacter infection rates from the FoodNet Fast platform for ten participating states from January 2010 to December 2019 (120 months). We estimated average monthly temperatures for the ten states for the study period using the National Climate and Data Center's Global Summary of the Day database. To assess the seasonal synchronization and determine the lag effect, we used serial cross-correlation analysis. To examine the associations between Campylobacter rates with ambient temperature and adjust for seasonality and trend, we applied a harmonic negative binomial mixed-effects regression model. We also estimated peak timing and amplitude for infections and temperature using the δ-method. Results Serial synchronization between monthly Campylobacter infection rates and ambient temperature was observed in all FoodNet Surveillance states except for California. A one-month delay in peak infection after the peak in temperature was detected in Colorado, Connecticut, Maryland, Minnesota, New Mexico, New York, and Oregon. After adjusting for seasonality and trend across ten states, the relative risk of infection rates increased by 5% with the increase in monthly average temperature by 5.45°C equivalent to a shift from 75th to 95th percentile (95%CI: 1.02–1.09, p &amp;lt; 0.002). Conclusions An increase in monthly average temperature is associated with an increased risk of Campylobacter infection after adjusting for common summer seasonal patterns. Knowledge of the relationship will potentially improve the reliability and accuracy of integrated early warning outbreak forecasts and could guide climate mitigation strategies. Funding Sources None.

Prevalence of private drinking water wells is associated with salmonellosis incidence in Maryland, USA: An ecological analysis using foodborne diseases active surveillance network (FoodNet) data (2007–2016)

Salmonellosis is a leading cause of foodborne illness worldwide. Salmonella infections have most often been associated with food-related risk factors, including the consumption of eggs and poultry. Recently, socioeconomic, agricultural and environmental factors, including drinking water source, have also been shown to influence the risk of salmonellosis. However, there are few data evaluating the association between consuming private well water and risk of Salmonella infections. Here, we examined the association between the prevalence of private drinking water wells and the incidence of salmonellosis in Maryland. Culture-confirmed salmonellosis case data (2007–2016) were obtained from the Foodborne Diseases Active Surveillance Network. Cases were linked by zip code with data from the Maryland well permits registry, the 2010 U.S. Census, the 2016 American Community Survey, and the USDA Agricultural Census. Well prevalence and salmonellosis incidence rates were calculated by zip code, and associations were evaluated using negative binomial regression models. From 2007 to 2016, a total of 8850 salmonellosis cases were reported in Maryland. Annual incidence rates ranged from 12.98 to 17.25 per 100,000 people. Prevalence of private wells in a zip code was statistically significantly associated with salmonellosis incidence at a statewide level (Incidence Rate Ratio [IRR] = 1.62; 95% Confidence Interval [CI] = 1.35, 1.93) and in the coastal zone of Maryland (IRR = 1.61; 95% CI = 1.31, 1.99). The presence of broiler chicken operations and the percentage of people living below the poverty level were also significantly associated with salmonellosis incidence at the zip code level in the coastal zone. To our knowledge, these are the first U.S. data to characterize the relationship between private drinking water wells and the risk of salmonellosis using an ecological study design. Our findings provide support for Salmonella testing of private wells in Maryland, as well as strengthening private well water regulations and improving the education of homeowners on well maintenance.

132. Emergence and Spread of Multidrug-resistant salmonella Serotype Infantis Infections in the United States, 2003–2018

BackgroundInfantis re-emerged as a leading Salmonella serotype when a multidrug-resistant (MDR) strain with a rare extended spectrum β-lactamase (ESBL) blaCTX-M-65 gene emerged among returned travelers from Peru in 2012 and then spread domestically. This strain has been isolated from chickens at slaughter and retail, and humans in outbreaks traced to chicken. We reviewed national surveillance data to determine incidence trends and antibiotic resistance among Infantis infections.MethodsWe reviewed data from 2003–2018 from the Foodborne Diseases Active Surveillance Network to determine the incidence and epidemiology of infections in 10 sites under surveillance; PulseNet to determine pulsed-field gel electrophoresis (PFGE) patterns; and National Antimicrobial Resistance Monitoring System (NARMS) to determine antimicrobial susceptibility testing (AST) results and resistance genes of isolates identified by whole genome sequencing (WGS). We defined MDR Infantis as having ceftriaxone resistance by AST and either the blaCTX-M-65 gene or one of 18 PFGE patterns linked to that gene by WGS.ResultsThe 2,154 patients with Infantis infection had a median age of 36 years and 57% were female; 86% had isolates from stool, 9% from urine, and 3% from blood. Only 10% reported foreign travel and 27% were hospitalized. The incidence of infections began increasing in 2010 and by 2017–2018 was 2-fold higher than the average during 2003–2009. During 2003–2018, 856 (88%) of 970 NARMS isolates had PFGE or WGS data; 48 isolates were MDR Infantis, and in addition to ceftriaxone and ampicillin resistance (by definition), all 48 were resistant to 3 or more antibiotic classes, 94% had decreased susceptibility to ciprofloxacin, and 67% were resistant to cotrimoxazole. During 2012–2016, 2% of isolates were MDR Infantis; this increased to 17% during 2017–2018 (Figure).ConclusionDuring the past decade, the incidence of Infantis infections markedly increased. This was likely driven by the emergence of an ESBL-producing strain that was initially associated with travel, and is now mostly domestically acquired and associated with consuming chicken. MDR Infantis now accounts for 1 in 5 Infantis infections. Public health strategies to reduce Salmonella contamination of chicken could help prevent these infections. Disclosures All Authors: No reported disclosures

Association between private drinking water wells and the incidence of Campylobacteriosis in Maryland: An ecological analysis using Foodborne Diseases Active Surveillance Network (FoodNet) data (2007–2016)

Campylobacter is a leading cause of bacterial foodborne illness in the United States. Campylobacter infections have most often been associated with food-related risk factors, such as the consumption of poultry and raw milk. Socioeconomic, agricultural and environmental factors, including drinking water source, can also influence the risk of campylobacteriosis. Approximately 19% of Maryland residents rely on private wells as their sole source of water. Given that the federal Safe Drinking Water Act does not regulate the water quality of private wells, these could be important non-foodborne transmission pathways for Campylobacter. To address this issue, data on the number of culture-confirmed cases of Campylobacter infection in Maryland between 2007 and 2016 were obtained from the Foodborne Diseases Active Surveillance Network. Cases were linked by zip code with data from the Maryland well permits registry, the 2010 U.S. Census, the 2016 American Community Survey, and the USDA Agricultural Census. Campylobacteriosis incidence rates and well prevalence were calculated by zip code. Negative binomial regression models were then constructed to evaluate the association between the prevalence of private wells, presence/absence of animal feeding operations and the incidence of campylobacteriosis across the physiographic provinces in Maryland. From 2007 to 2016, a total of 5746 cases of campylobacteriosis were reported in Maryland, and annual incidence rates ranged from 6.65 to 11.59 per 100,000 people. In our statewide analysis, a significant positive association was observed between well prevalence and increased campylobacteriosis incidence at the zip code level (Incidence Rate Ratio (IRR) = 1.35, 95% Confidence Interval (CI) = 1.11, 1.63). A significant positive association was also observed between well prevalence and increased campylobacteriosis incidence in the Appalachian and Coastal provinces of Maryland (IRR = 2.94, 95% CI = 1.11, 7.76 and IRR = 1.70, 95% CI = 1.25, 2.31, respectively). The presence of broiler chicken operations, increasing median age and percentage of residents living in poverty were also significantly associated with campylobacteriosis incidence at the zip code level in some physiographic provinces in Maryland. To our knowledge, these are the first US data to demonstrate an association between prevalence of private wells and campylobacteriosis incidence at the zip code level.

Preliminary Incidence and Trends of Infections with Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2016-2019.

To evaluate progress toward prevention of enteric illnesses, the Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program monitors the incidence of laboratory-diagnosed infections caused by eight pathogens transmitted commonly through food at 10 U.S. sites.* This report summarizes preliminary 2019 data and describes changes in incidence compared with that during 2016-2018. The incidence of enteric infections caused by these eight pathogens reported by FoodNet sites in 2019 continued to increase or remained unchanged, indicating progress in controlling major foodborne pathogens in the United States has stalled. Campylobacter and Salmonella caused the largest proportion of illnesses; trends in incidence varied by Salmonella serotype. Widespread adoption of whole genome sequencing (WGS) of bacteria has improved the ability to identify outbreaks, emerging strains, and sources of pathogens. To maximize the potential of WGS to link illnesses to particular sources, testing of isolates by clinical and public health laboratories is needed. Reductions in Salmonella serotype Typhimurium suggest that targeted interventions (e.g., vaccinating chickens and other food animals) might decrease human infections. Reducing contamination during food production, processing, and preparation will require more widespread implementation of known prevention measures and of new strategies that target particular pathogens and serotypes.