Answer
Although a negative throat culture finding essentially rules out the diagnosis of streptococcal pharyngitis, a positive culture finding unfortunately cannot be used to differentiate between acute infection and asymptomatic carriage. Some studies have reported that the degree of positivity of the culture may, by quantifying the load of organisms, assist in making this differentiation. In practice, however, assuming that all positive results in appropriately cultured patients represent streptococcal infection and accepting that some degree of overtreatment is inevitable is probably best.
The video below demonstrates a throat culture.
Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!
Media Gallery
-
Invasive soft tissue infection due to Streptococcus pyogenes. This child developed fever and soft-tissue swelling on the fifth day of a varicella-zoster infection. Leading edge aspirate of cellulitis grew S pyogenes. Although the patient responded to intravenous penicillin and clindamycin, operative débridement was necessary because of clinical suspicion of early necrotizing fasciitis.
-
Streptococcus group A infections. Beta hemolysis is demonstrated on blood agar media.
-
Streptococcus group A infections. M protein.
-
Streptococcus group A infections. Erysipelas is a group A streptococcal infection of skin and subcutaneous tissue.
-
Streptococcus group A infections. White strawberry tongue observed in streptococcal pharyngitis. Image courtesy of J. Bashera.
-
Streptococcus group A infections. Streptococcal rash. Image courtesy of J. Bashera.
-
Group A Streptococcus on Gram stain of blood isolated from a patient who developed toxic shock syndrome.
-
Streptococcus group A infections. Necrotizing fasciitis of the left hand in a patient who had severe pain in the affected area.
-
Streptococcus group A infections. Patient who had had necrotizing fasciitis of the left hand and severe pain in the affected area (from Image 8). This photo was taken at a later date, and the wound is healing. The patient required skin grafting.
-
Streptococcus group A infections. Gangrenous streptococcal cellulitis in a patient with diabetes.
-
Erythema secondary to group A streptococcal cellulitis.
-
Invasive soft tissue infection due to Streptococcus pyogenes. This child developed fever and soft-tissue swelling on the fifth day of a varicella-zoster infection. Leading edge aspirate of cellulitis grew S pyogenes. Although the patient responded to intravenous penicillin and clindamycin, operative débridement was necessary because of clinical suspicion of early necrotizing fasciitis.
-
Streptococcus group A infections. Necrotizing fasciitis rapidly progresses from erythema to bullae formation and necrosis of skin and subcutaneous tissue.
-
Throat swab. Video courtesy of Therese Canares, MD; Marleny Franco, MD; and Jonathan Valente, MD (Rhode Island Hospital, Brown University).
of
14
