Final answer:
The client with pulmonary tuberculosis is the one who requires a negative pressure room to prevent the spread of tuberculosis, which is an airborne pathogen.
Step-by-step explanation:
Among the listed clients, the one requiring a negative pressure room is the client with pulmonary tuberculosis (D). Negative pressure rooms are designed to contain airborne pathogens such as Mycobacterium tuberculosis, which causes TB, by preventing the air from the room from flowing out into adjacent areas and potentially infecting other individuals. Patients with tuberculosis are highly infectious, and as such, they need to be isolated in an environment that can help control the spread of the infection.
On the other hand, patients with pneumonia (A), caused by Streptococcus pneumoniae, pharyngitis (B), which could be caused by viruses or bacteria such as Corynebacterium diphtheriae, and those with draining leg wounds (C), potentially caused by Staphylococcus aureus, do not generally require such stringent airborne precautions unless there is a suspicion or confirmation of an airborne-transmissible pathogen.
A client with pulmonary tuberculosis requires a negative pressure room to prevent the spread of the infectious airborne pathogen. Other conditions listed do not routinely necessitate negative pressure isolation unless there are specific infectious agents involved that are spread through the airborne route.