Is this sexual harassment ?

I (male) was fixing an IT issue for an accountant (female) who brought her laptop into my temporary office. A male co-worker stuck his head in the door and said:

'You must be important, you've got Kathy* on her knees'.

(Kathy was kneeling looking at her laptop beside me).

* not real name

Sounds vaguely inappropriate to me, but not sure if Kathy was offended or if I can do anything about it. Bringing it up with Kathy ? Let it go ? Bring it up with the male co-worker ? HR ?