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Background Vibriosis causes an estimated 80,000 illnesses and 100 deaths in the United States each year. Commonly reported exposures include consuming raw or undercooked seafood and contact with seawater. To facilitate case ascertainment and better understand the epidemiology of vibriosis, CDC requested inclusion of positive culture-independent diagnostic testing (CIDT) cases to the 2017 case definition. We reviewed confirmed (culture positive) and probable (CIDT positive) cases in Tennessee (TN) from 2017-2021. Methods Vibrio reports from clinical and state public health laboratories were reviewed. Demographic, clinical, and exposure data were collected through routine case interviews using The Cholera and Other Vibrio Illness Surveillance (COVIS) Report. Confirmed and probable cases were described and compared using Epi Info 7. Results A total of 164 Vibrio cases were reported from 44 counties across TN. In total, 135 (82%) cases were interviewed including 72 (53%) confirmed cases (all sources) and 63 (47%) probable cases. Half of cases from each case status were 40-69 years old. Twenty-four percent of probable cases versus 7% of confirmed cases were under 10 years old. Of confirmed cases, 64% were males compared to 51% of probable cases. Most cases (90% of confirmed and 75% of probable cases) were among non-Hispanic white population. Almost all probable cases (97%) reported gastrointestinal (GI) symptoms. Among confirmed cases, 70% reported non-GI symptoms such as cellulitis. Thirty three percent of both confirmed and probable cases were hospitalized. Confirmed cases were more likely to report travel out of state (OR 5.1, p-value < 0.0001) and exposure to seawater (OR 3.4, p-value 0.002) compared to probable cases. When comparing confirmed cases from stool specimens (27 cases) to probable cases, travel out of state remained significant (OR 4.8, p-value 0.0001) as well as seafood consumption (OR 6.8, p-value 0.0008). Conclusion Demographic and clinical features differed between confirmed and probable cases. Out of state travel, seafood consumption, and exposure to seawater were reported more often by confirmed cases. Reflex culturing is recommended to better facilitate case ascertainment and understand the epidemiology of vibriosis. Disclosures All Authors: No reported disclosures.

Background Acute gastroenteritis (AGE) is a common reason for children to receive medical care. However, the viral etiology of AGE illness is not well described in the post–rotavirus vaccine era, particularly in the outpatient (OP) setting. Methods Between 2012 and 2015, children 15 days through 17 years old presenting to Vanderbilt Children’s Hospital, Nashville, Tennessee, with AGE were enrolled prospectively from the inpatient, emergency department, and OP settings, and stool specimens were collected. Healthy controls (HCs) were enrolled and frequency matched for period, age group, race, and ethnicity. Stool specimens were tested by means of reverse-transcription real-time quantitative polymerase chain reaction for norovirus, sapovirus, and astrovirus RNA and by Rotaclone enzyme immunoassay for rotavirus antigen, followed by polymerase chain reaction verification of antigen detection. Results A total of 3705 AGE case patients and 1563 HCs were enrolled, among whom 2885 case patients (78%) and 1110 HCs (71%) provided stool specimens that were tested. All 4 viruses were more frequently detected in AGE case patients than in HCs (norovirus, 22% vs 8%, respectively; rotavirus, 10% vs 1%; sapovirus, 10% vs 5%; and astrovirus, 5% vs 2%; P Conclusions Norovirus remains the most common virus detected in all settings, occurring nearly twice as frequently as the next most common pathogens, sapovirus and rotavirus. Combined, norovirus, sapovirus, rotavirus, and astrovirus were associated with almost half of all AGE visits and therefore are an important reason for children to receive medical care.

Campylobacteriosis is the most common bacterial foodborne illness in the United States and is frequently associated with foods of animal origin. The goals of this study were to compare clinical and non-clinical Campylobacter populations from Tennessee (TN) and Pennsylvania (PA), use phylogenetic relatedness to assess source attribution patterns, and identify potential outbreak clusters. Campylobacter isolates studied (n = 3080) included TN clinical isolates collected and sequenced for routine surveillance, PA clinical isolates collected from patients at the University of Pennsylvania Health System facilities, and non-clinical isolates from both states for which sequencing reads were available on NCBI. Phylogenetic analyses were conducted to categorize isolates into species groups and determine the population structure of each species. Most isolates were C. jejuni (n = 2132, 69.2%) and C. coli (n = 921, 29.9%), while the remaining were C. lari (0.4%), C. upsaliensis (0.3%), and C. fetus (0.1%). The C. jejuni group consisted of three clades, most non-clinical isolates were of poultry (62.7%) or cattle (35.8%) origin, and 59.7 and 16.5% of clinical isolates were in subclades associated with poultry or cattle, respectively. The C. coli isolates grouped into two clades, most non-clinical isolates were from poultry (61.2%) or swine (29.0%) sources, and 74.5, 9.2, and 6.1% of clinical isolates were in subclades associated with poultry, cattle, or swine, respectively. Based on genomic similarity, we identified 42 C. jejuni and one C. coli potential outbreak clusters. The C. jejuni clusters contained 188 clinical isolates, 19.6% of the total C. jejuni clinical isolates, suggesting that a larger proportion of campylobacteriosis may be associated with outbreaks than previously determined.

Background Campylobacter causes an estimated 1.5 million infections each year in the United States. Of those, approximately 448,400 infections are caused by antimicrobial resistant strains, including strains resistant to fluoroquinolones (e.g., nalidixic acid and ciprofloxacin), which are commonly used to treat campylobacteriosis. Campylobacter infection is commonly attributed to consuming poultry products. We compared exposure data between fluoroquinolone-resistant and pan-susceptible Campylobacter cases reported in 2016-2018 to assess attribution. Methods Broth microdilution was performed on Campylobacter isolates at CDC to determine the minimum inhibitory concentration for nine antimicrobial drugs. Whole genome sequencing (WGS) was performed at the Tennessee (TN) State Public Health Laboratory and the sequence data were analyzed at CDC to determine the genetic resistance determinants. Exposure data was collected through routine case interviews. Exposures among cases with fluoroquinolone-resistant infection and cases with no resistance to antimicrobials were compared. Results A total of 606 Campylobacter isolates from TN were submitted to CDC NARMS. Of those, 123 (20%) isolates were resistant to fluoroquinolones and 304 (50%) isolates were pan-susceptible. The gyr A (86) resistance gene was detected in 46/54 (85%) of resistant isolates. Exposure data were available for 59 (48%) fluoroquinolone-resistant cases and 186 (61%) pan-susceptible cases. Consumption of chicken (OR 2.1, p-value 0.03) and handling raw seafood (OR 3.1, p-value 0.03) were significantly associated with fluoroquinolone-resistance. More fluoroquinolone-resistant cases reported international travel compared to pan-susceptible cases (15% versus 4%) with OR 4.6, and p-value 0.004. Conclusion Fluoroquinolone-resistant Campylobacter infections were acquired domestically and internationally. Exposure to chicken products and handling raw seafood were reported more often among fluoroquinolone-resistant cases. Whole genome sequencing of Campylobacter isolates provides predicted resistance data. Coupling predicted resistance data with exposure data facilitates better understanding of source attribution of different strains. Disclosures All Authors: No reported disclosures

Background Culture-independent diagnostic tests (CIDTs) are increasingly used to identify enteric pathogens. However, foodborne illness surveillance systems have relied upon culture confirmation to estimate disease burden and identify outbreaks through molecular subtyping. This study examined the impacts of CIDT and estimated costs for culture verification of Shigella, Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Campylobacter at the Tennessee Department of Health Public Health Laboratory (PHL). Methods This observational study included laboratory and epidemiological surveillance data collected between years 2013-2016 from patients with the reported enteric illness. We calculated pathogen recovery at PHL based on initial diagnostic test type reported at the clinical laboratory. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated with modified Poisson regression. Estimates of cost were calculated for pathogen recovery from CIDT-positive specimens compared to recovery from culture-derived isolates. Results During the study period, PHL received 5553 specimens from clinical laboratories from patients with the enteric illness. Pathogen recovery was 57% (984/1713) from referred CIDT-positive stool specimens and 95% (3662/3840) from culture-derived isolates (PR, 0.61 [95% CI, .56-.66]). Pathogen recovery from CIDT-positive specimens varied based on pathogen type: Salmonella (72%), Shigella (64%), STEC (57%), and Campylobacter (26%). Compared to stool culture-derived isolates, the cost to recover pathogens from 100 CIDT-positive specimens was higher for Shigella (US $6192), Salmonella (US $18373), and STEC (US $27783). Conclusions Pathogen recovery was low from CIDT-positive specimens for enteric bacteria. This has important implications for the current enteric disease surveillance system, outbreak detection, and costs for public health programs.

Background Postdiarrheal hemolytic-uremic syndrome (D+HUS) following Shiga toxin-producing Escherichia coli (STEC) infection is a serious condition lacking specific treatment. Host immune dysregulation and genetic susceptibility to complement hyperactivation are implicated in non-STEC-related HUS. However, genetic susceptibility to D+HUS remains largely uncharacterized. Methods Patients with culture-confirmed STEC diarrhea, identified through the Centers for Disease Control and Prevention FoodNet surveillance system (2007-2012), were serotyped and classified by laboratory and/or clinical criteria as having suspected, probable, or confirmed D+HUS or as controls and underwent genotyping at 200 loci linked to nondiarrheal HUS or similar pathologies. Genetic associations with D+HUS were explored by multivariable regression, with adjustment for known risk factors. Results Of 641 enrollees with STEC O157:H7, 80 had suspected D+HUS (41 with probable and 32 with confirmed D+HUS). Twelve genes related to cytokine signaling, complement pathways, platelet function, pathogen recognition, iron transport, and endothelial function were associated with D+HUS in multivariable-adjusted analyses (P ≤ .05). Of 12 significant single-nucleotide polymorphisms (SNPs), 5 were associated with all levels of D+HUS (intergenic SNP rs10874639, TFRC rs3804141, EDN1 rs5370, GP1BA rs121908064, and B2M rs16966334), and 7 SNPs (6 non-complement related) were associated with confirmed D+HUS (all P < .05). Conclusions Polymorphisms in many non-complement-related genes may contribute to D+HUS susceptibility. These results require replication, but they suggest novel therapeutic targets in patients with D+HUS.

Background In the United States, surveillance of norovirus gastroenteritis is largely restricted to outbreaks, limiting our knowledge of the contribution of sporadic illness to the overall impact on reported outbreaks. Understanding norovirus transmission dynamics is vital for improving preventive measures, including norovirus vaccine development. Methods We analyzed seasonal patterns and genotypic distribution between sporadic pediatric norovirus cases and reported norovirus outbreaks in middle Tennessee. Sporadic cases were ascertained via the New Vaccine Surveillance Network in a single county, while reported norovirus outbreaks from 7 middle Tennessee counties were included in the study. We investigated the predictive value of sporadic cases on outbreaks using a 2-state discrete Markov model. Results Between December 2012 and June 2016, there were 755 pediatric sporadic norovirus cases and 45 reported outbreaks. Almost half (42.2%) of outbreaks occurred in long-term care facilities. Most sporadic cases (74.9%) and reported outbreaks (86.8%) occurred between November and April. Peak sporadic norovirus activity was often contemporaneous with outbreak occurrence. Among both sporadic cases and outbreaks, GII genogroup noroviruses were most prevalent (90.1% and 83.3%), with GII.4 being the dominant genotype (39.0% and 52.8%). The predictive model suggested that the 3-day moving average of sporadic cases was positively associated with the probability of an outbreak occurring. Conclusions Despite the demographic differences between the surveillance populations, the seasonal and genotypic associations between sporadic cases and outbreaks are suggestive of contemporaneous community transmission. Public health agencies may use this knowledge to expand surveillance and identify target populations for interventions, including future vaccines.

We investigated a gastrointestinal illness cluster among persons who attended a baseball tournament (200 teams) during July 2015. We interviewed representatives of 19 teams; illness was reported among only the 9 (47%) teams that stayed at Hotel A (p.01). We identified 55 primary cases. A case-control study demonstrated that pool exposure at Hotel A was significantly associated with illness (odds ratio: 7.3; 95% confidence interval: 3.6, 15.2). Eight out of nine (89%) stool specimens tested were positive for Cryptosporidium, with C. hominis IfA12G1 subtype identified in two specimens. The environmental health assessment detected a low free available chlorine level, and pool water tested positive for E. coli and total coliforms. A possible diarrheal contamination event, substantial hotel pool use, and use of cyanuric acid might have contributed to this outbreak and magnitude. Aquatic facilities practicing proper operation and maintenance (e.g., following the Centers for Disease Control and Prevention’s Model Aquatic Health Code) can protect the public’s health.

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.

We describe multidrug-resistant (MDR) Salmonella Heidelberg infections associated with mechanically separated chicken (MSC) served at a county correctional facility. Twenty-three inmates met the case definition. All reported diarrhea, 19 (83%) reported fever, 16 (70%) reported vomiting, 4 (17%) had fever ≥103°F, and 3 (13%) were hospitalized. A case-control study found no single food item significantly associated with illness. Salmonella Heidelberg with an indistinguishable pulsed-field gel electrophoresis pattern was isolated from nine stool specimens; two isolates displayed resistance to a total of five drug classes, including the third-generation cephalosporin, ceftriaxone. MDR Salmonella Heidelberg might have contributed to the severity of illness. Salmonella Heidelberg indistinguishable from the outbreak subtype was isolated from unopened MSC. The environmental health assessment identified cross-contamination through poor food-handling practices as a possible contributing factor. Proper hand-washing techniques and safe food-handling practices were reviewed with the kitchen supervisor.