Use CSSearchQuery in QLPreviewingController?

Question

When implementing a QLPreviewingController, we only get the Spotlight uniqueIdentifier but not the actual CSSearchableItem. I thought I could use CSSearchQuery with a query like this

uniqueIdentifier == "\(identifier)"

to fetch the CSSearchableItem of the selected item from Spotlight. However, I always receive an error:

Error Domain=NSCocoaErrorDomain Code=4099 "Couldn’t communicate with a helper application."

Is it not possible to call Spotlight from a QuickLook Preview extension? Is there another way to retrieve the CSSearchableItem for the item to be previewed?