by Pe­ter Set­low — Rarely does news come along that threat­ens to over­turn our cher­ished be­liefs. Since early af­ter the dis­cov­ery of tu­ber­cle bacilli by Robert Koch in 1882, the my­cobac­te­ria have been con­sid­ered not to be spore for­m­ers. Now this is be­ing chal­lenged by a new re­port.