Roles of Staphylococcus Aureus in Intestine

Introduction: Staphylococcus aureus are generally well-known as intoxication foodborne pathogens, and many people annually have suffered from the foodborne illness. Although the pathogen is also isolated from human intestine, and S. aureus cells can be ingested with food. The roles of S. aureus in intestine have not been studied yet.

Purpose: The objective of this study was to evaluate the roles of S. aureus in intestine by in vivo study.

Methods: Five weeks old of C57bl/6 mice (n=6/group) were purchased from Orientbio in Korea. After 1 week acclimation, 100 μL of S. aureus (10⁸ CFU/mL) were orally injected to the mice for every 2 days during 2 weeks, and the sham group were injected with same amount of phosphate buffer solution. After 1 week, the mice were scarified, and microbiological analysis, anatomical analysis, immunological analysis, and histopathological analysis were conducted.

Results: S. aureus colonies were isolated from sham and S. aureus-injected group at 3 and 6 log CFU/g, respectively. In anatomical analysis, mice weight were not significantly different, but the length of small intestine and colon in S. aureus-injected group were significantly shorter (P<0.05) than those of sham group. Nitric oxide concentrations in blood samples were slightly lower in S. aureus-injected group. In histopathological analysis, there were no difference in histological aspects in small intestine and large intestine for shame and S. aureus-injected group.

Significance: These results indicates that orally ingested S. aureus can exist in intestine, and  potentially promotes microenvironmental conditions that are conducive to the development of inflammatory disease.