An unexpected inhibitory effect of rapamycin against germination of spores of Bacillus brevis strain Nagano.

Rapamycin is used in medicine as an immunosuppressive agent (Sirolimus; Rapamune) although discovered as an antifungal agent. It is thought not to have antibacterial activity. Surprisingly, we found that rapamycin inhibits the germination of Bacillus brevis Nagano spores, but is inactive against Bacillus brevis Nagano vegetative cells.