Effects of staphylococcal enterotoxin on ciliary activity and histology of the sinus mucosa

The results of our study suggest that Staphylococcus aureus enterotoxin A (SEA) may play an important role in the pathogenesis of rhinosinusitis by ciliostatic effects at high concentrations, and by a different mechanism at low concentrations.

To investigate the in vitro effects of SEA on ciliary activity and its in vivo effects on histology of the sinus mucosa.

The in vitro effects of SEA on ciliary activity at different concentrations and exposure time were investigated using maxillary sinus mucosa harvested from experimental rabbits. After in vivo instillation of different concentrations (high and low dose) of SEA into the maxillary sinus, ciliary beat frequency (CBF) and histologic findings of the maxillary sinus mucosa were examined.

After exposure to low doses of SEA (0.03 and 0.3 ng/ml), CBF did not decrease, but after exposure to high doses of SEA (1.5, 3, and 30 ng/ml), CBF decreased significantly as a function of time. At 24 h after instillation of high-dose SEA (30 ng/ml) into the sinus, CBF decreased significantly and rhinosinusitis was induced after 7 days. Although no alteration was observed in the CBF of the sinus mucosa after instillation of low-dose SEA (0.3 ng/ml), histological findings of rhinosinusitis including subepithelial edema and inflammatory cell infiltration were observed.