The potential association between extraintestinal infections and food has been under scrutiny by Dutch health authorities, although establishing a direct link remains a challenging task, according to findings from the National Institute for Public Health and the Environment (RIVM).
Extraintestinal infections, which manifest outside the intestines, particularly in the urinary tract and bloodstream, may result from the infiltration of bacteria from feces into the urinary tract. Growing evidence suggests that food might play a role in these infections, although confirming a definitive connection poses challenges.
To explore this potential correlation, the RIVM conducted a comprehensive review of scientific literature. While the investigation uncovered indications of a possible link between food and extraintestinal infections, concrete evidence supporting food as a direct cause was not found.
E. coli, known for causing both gastrointestinal and urinary tract infections, was a focal point of the study. However, the strains responsible for urinary tract infections differed from those associated with gastrointestinal cases.
The research highlighted that extraintestinal pathogenic E. coli (ExPEC) appeared to be a predominant cause of urinary tract and bloodstream infections in the Netherlands. Consequently, scientists directed their attention toward establishing a connection between infections caused by ExPEC and food.
Demonstrating the origin of bacteria causing urinary tract infections from food requires meticulous investigation. This involves confirming whether the bacterial strain in humans matches that found in food or animals and then establishing a correlation between the consumption of the implicated food and the development of extraintestinal infections. Such investigations, however, are resource-intensive and time-consuming, noted the RIVM.
Examining the data from 2019 and 2022, scientists identified E. coli as the primary pathogen leading to urinary tract and bloodstream infections in the Netherlands, with Klebsiella pneumoniae and Enterococcus faecalis occurring less frequently.
The literature review focused on articles related to ExPEC infections linked to food published between 2010 and February 2023. Poultry meat emerged as a potential significant source, although researchers emphasized that this conclusion was drawn from indirect evidence. The impact of eggs, raw milk, and fruits and vegetables appeared minimal, albeit based on a limited number of studies.
The variability in the incubation period of extraintestinal pathogens, complicating the demonstration of a relationship with food, was noted by the researchers. Instances of ExPEC outbreaks possibly tied to food were acknowledged, but confirmation of the source was lacking, often due to incomplete data collection or reporting in outbreak investigations.
While similar strains of ExPEC were observed in both animals and humans, there is currently no quantitative evidence of the transmission of ExPEC through food leading to urinary tract infections.
The researchers proposed establishing a comprehensive database involving the sequencing and analysis of ExPEC strains from clinical isolates, farm animals, and food. This approach could aid in monitoring and investigating clusters based on sequence data, providing valuable insights for source attribution studies and enhancing our understanding of the potential link between food and extraintestinal infections.
