Title : Impact of human milk oligosaccharides on the growth of early life pathogenic gut bacteria
Abstract:
Antibiotics are widely used to prevent and/or treat early life gut infections but their overuse has raised global concerns about antibiotic resistance. Studies have shown that infants fed with breastmilk have a lower incidence of intestinal infections compared to those fed with infant formula. This observation stimulated scientific interest in the prebiotic and anti-pathogenic properties of breastmilk, specifically human milk oligosaccharides (HMOs). HMOs are non-digestible sugars that promote the growth of beneficial gut bacteria, such as Bifidobacterium and Bacteroides, while inhibiting the growth of pathogenic bacteria. However, research has focused on the effects of pooled HMO mixtures, making it challenging to determine the specific impacts of individual HMOs.
This study evaluates the effects of single-structure HMOs and galacto-oligosaccharides (GOS) on the growth of key early-life gut pathogens Escherichia coli, Salmonella enterica, Yersinia enterocolitica, and Clostridium perfringens. Growth curves of these pathogens were generated by measuring the optical density over a 16-hour period. The area under the curve was used as an overall growth parameter to compare untreated versus HMO-treated pathogens. The most effective HMO-pathogen combination was further investigated by colony forming unit (CFU) assays, testing in different growth media, and evaluation with clinical strains to confirm HMO-specific efficacy.
S. enterica exhibited the most significant growth inhibition by HMOs and GOS, while C. perfringens demonstrated trends of both increased and decreased growth in response to the HMOs and GOS. Among the tested oligosaccharides, only 3’GL and GOS significantly impaired the pathogenic growth of all included Gram-negative facultative anaerobes. The overall screening revealed that slight structural differences in HMOs led to varying growth effects across the tested pathogens.
Overall, the HMOs were most effective against S. enterica, with 3’GL and GOS emerging as the most promising candidates for studying mechanisms and early-life dietary applications due to their anti-pathogenic and structure-specific effects.
