Staphylococcus aureus in inflammatory bowel disease

The potential role of superantigens in inflammatory bowel disease (IBD), particularly Crohn disease, has been broached in studies of the functions of T cell receptors. Staphylococcal cells have been found in intestinal lymph follicles of IBDs. To clarify a role of staphylococcal superantigens in IBD, we attempted to determine whether Staphylococcus aureus could be detected in intestinal mucosa, including surgical specimens and lymph follicles of initial cases.

One-hundred-and-six colonic and ileal specimens were obtained from 38 Crohn disease, 25 ulcerative colitis and 36 non-IBD patients through therapeutic surgery or endoscopic biopsy. In Crohn disease, 23 surgical specimens and 11 biopsy specimens from initial cases were included. DNA was extracted with phenol-chloroform after homogenization and proteinase K treatment in 73 mucosal specimens. Using an inverted microscope, lymph follicle tissue was microdissected from the remaining 33, mostly biopsy, specimens. DNA was then extracted by freeze-thawing. A coagulase gene characteristic of S. aureus was sought. A nested polymerase chain reaction was performed utilizing primers that amplify a region of the coagulase gene. Polymerase chain reaction products were analyzed with polyacrylamide gel electrophoresis.

Only one surgically resected colonic specimen, from a 42-year-old male ulcerative colitis patient, registered positive staphylocoagulase amplification.

Staphylococcal superantigens are not involved in either the early lesions or the established lesions of Crohn disease. However, S. aureus infection occasionally may occur during the course of IBD.