How frequent is bacterial superinfection of the pharynx in infectious mononucleosis? Observations on incidence, recognition, and management with antibiotics.

Throat cultures from 133 patients with infectious mononucleosis were compared with cultures from 2,881 patients who were seen during the same period because of pharyngitis. Less than 3 per cent of the cultures from each group contained Group A beta hemolytic streptococci. The inflamed pharynx and necrotic tonsils of infectious mononucleosis are seldom subject to bacterial superinfection, either initially or during the course of the illness. There is no indication for routine use of antibiotics when infectious mononucleosis is diagnosed. Should, however, a throat culture indicate presence of a bacterial pathogen, any appropriate antibiotic except ampicillin may be used without increasing the incidence of skin rash.