BP, can they reach such a conclusion from a chest scan?
Seems unlikely to me
For them to say "Clinton had a mild, non-contagious bacterial pneumonia".
Indicates that the scan shows a resolving pneumonia (this can be determined from the pattern of the pneumonic consolidation in the lung), therefore if it is resolving, then it is in a non contagious phase.
The pattern of consolidation on the scan also gives pointers as to the causative infection. Bacterial and viral infection produce different patterns of consolidation.
So yes the imaging can suggest that it is bacterial and resolving .