The concept of a wormhole is, of course, highly speculative. None the less, such a phenomenon could take many forms - most simple something which to outside observers looks like a blackhole on each end of the wormhole. Alternatively, a traversable wormhole (see for example Morris & Thorne 1988; which has the same basic topology but no horizon), could still behave for the most part* like a normal, massive object.
In either case, if one end were 'swallowed' by a blackhole, it is unclear to me whether it would remain stable (i.e. remain a wormhole). In the case of a non-traversable wormhole, if it remained stable, it would continue to look like a blackhole on each end --- one end of which now merged with another blackhole, and subsequently more massive. A traversable wormhole on the other hand could (extremely hypothetically) still remain traversable if there were enough exotic matter, or it could retain the horizon from the blackhole it merged with and be no-longer traversable.
All wormhole metrics that I've seen are more or less symmetric, and thus either have no horizon, or horizons on both ends... I don't think it would be possible to have a horizon on only one side --- allowing something to fall into an apparent blackhole on one side, and come out of a wormhole on the other. Even so, however, remember that a blackhole isn't a magic vacuum --- and wouldn't 'suck in' the 'entire universe'.
*A traversable wormhole is believed to require some sort of 'exotic matter' in the neck, which may behave somewhat differently...