BACKGROUND: Salmonella represents a substantial public health burden in Georgia with approximately 2,000 cases yearly. The Georgia Department of Public Health interviews Salmonella cases to collect information on demographics, symptoms, and potential food and other exposures. In 2014, the interview form was standardized across all Foodborne Diseases Active Surveillance Network (FoodNet) sites. From 2009 to 2015, Salmonella Javiana has been the most common serotype in Georgia. A single Pulsed Field Gel Electrophoresis (PFGE) pattern comprises approximately 29% of S. Javiana isolates. This common pattern may have different demographic and exposure characteristics compared to other patterns.
METHODS: Demographic, symptom, and exposure data for S. Javiana cases from 2013-2015 were linked with PFGE results obtained from the Georgia Public Health Laboratory. The most common PFGE pattern was classified as endemic, patterns with three or fewer annual isolates as rare, and others as less common. Georgia Department of Natural Resources definitions were used to assign geographic regions. USDA urban/rural codes were used to define rurality. Eighteen exposures were selected based on a subset of FoodNet variables and common food and animal vehicles associated with S. Javiana during outbreak investigations. Analysis of exposure data was limited to cases for whom at least 90% of exposure variables were complete. Analysis was performed comparing endemic patterns to non-endemic (rare and less common) patterns using SAS version 9.4 using a p-value of 0.05 for significance.
RESULTS: There were 1,126 S. Javiana cases reported from 2013 to 2015. Three hundred twenty-nine isolates (29.3%) were the endemic pattern, 522 (46.5%) were less common, and 271 (24.2%) were rare; 548 (48.8%) of cases were female; 713 (72.8%) were White and 233 (23.8%) were Black; 695 (61.7%) were under the age of 18. Children were more likely to have an endemic pattern than adults (p=0.009). There were no significant racial or gender differences and no association by geographic region or rurality. Two hundred thirty-three (20.7%) cases were included in the exposure analysis. Drinking well water (p=0.028) and contact with live poultry (p=0.039) were associated with infection by the endemic pattern. Eating chicken prepared outside the home was negatively associated (p=0.044).
CONCLUSIONS: Children were significantly more likely to have infections with the endemic S. Javiana pattern than adults. The association with well water and live poultry contact implies an environmental source. The lack of an association with geographic regions or rurality makes it harder to determine which factors may be responsible.