We generalize a description of twisted K-theory for torsion twists using bundle gerbes to the K-theory of operator algebras. Thus, we are able to give a nice geometric description of K(C(M,A)), where A is a bundle of C*-algebras over M with structure group Aut(A). In a second part of the talk we will explain some relation of our construction to the notion of 2-vector bundles and generalize the latter using bimodules over certain von Neumann algebras. In particular, we will use the equivalence between bimodules over type III1-factors and endomorphisms and discuss a topology on the space of finite-index endomorphisms.