TSST-1-producing Staphylococcus aureus in bullous pemphigoid

A potential role of S. aureus in BP was explored by examining the colonization rate in patients with new-onset disease, compared to age- and sex-matched controls. S. aureus colonization was observed in 85% of BP lesions; 3-6-fold higher than the nares or unaffected skin from the same patients (p≤0.003) and 6-fold higher than nares or skin of controls (p≤0.0015). Furthermore, 96% of the lesional isolates produced the toxic shock syndrome toxin-1 (TSST-1) superantigen and most of these additionally exhibited homogeneous expression of the enterotoxin gene cluster (EGC) toxins. TSST-1 neutralizing antibodies were not protective against colonization. However, S. aureus colonization was not observed in patients who had recently received antibiotics and addition of antibiotics with staphylococcal coverage eliminated S. aureus and resulted in clinical improvement. This study demonstrates that TSST-1S. aureus is prevalent in BP lesions and suggests that early implementation of antibiotics may be of benefit. Further, our results suggest that S. aureus colonization could provide a source of infection in BP patients, particularly in the setting of high dose immunosuppression.