Upper respiratory tract infection (URI) is a nonspecific term used to describe acute infections involving the nose, paranasal sinuses, pharynx, larynx, trachea, and bronchi. The prototype is the illness known as the common cold, which is discussed here, in addition to pharyngitis, sinusitis, and tracheobronchitis.ther less common causes of bacterial pharyngitis include group C beta-hemolytic streptococci, Corynebacterium diphtheriae, Neisseria gonorrhoeae, Arcanobacterium haemolyticum, Chlamydophila (formerly Chlamydia) pneumoniae, Mycoplasma pneumoniae, and herpes simplex virus.