It is estimated that over 48 million people (1 in 6) are affected by a foodborne illness (FBI) every year in the United States. A subset of patients affected by FBIs develop post-infectious sequelae that lead to chronic diseases such as irritable bowel syndrome, Crohn’s disease, reactive arthritis, and Guillain-Barré syndrome. This study focused on Salmonella and Campylobacter; pathogens that cause 2 million illnesses annually and disproportionately affect Hispanics, children, and the elderly, with associated costs for acute outcomes approaching $5 billion.

The study followed Campylobacter and Salmonella cases that began at the initial report to the health department surveillance system and ended a year after the onset of acute symptoms. We gathered information on patient risk factors, genetics, and the development of new symptoms, and collected and banked microbial samples linked to patients’ acute infections and performed advanced testing to determine the microbial factors that contributed to specific acute and long-term sequelae. All recruitment, interviews, sample preparation, microbial testing and data analysis were conducted by trained graduate and undergraduate students.

Our long-term goal was to develop recommendations for clinicians to more appropriately address the follow-up of FBIs, and to inform the improvement of therapeutics and prevention strategies. To accomplish this, we needed to advance our understanding of the mechanisms and genetics of pathogenesis, including how patient factors (demographics, ethnicity, co-morbidities, genetics, microbiome), mechanisms of disease onset, and microbial factors (subtype, virulence factors, antibiotic resistance) intersected to cause chronic outcomes. This study took advantage of a decade of collaboration between researchers and health departments that maintain robust surveillance systems, while training graduate and undergraduate students in this field.