This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Cellulitis is most commonly caused by:September 2008, 2010 
Select and explain. 
A. Clostridia, B. Staphylococci, C. Streptococci, D. H. Influenzae
C: Streptococci
Answer: C: Streptococci 
Explanation: Ans. C: StreptococciIn individuals with normal host defenses, the most common causative organisms are streptococci, followed by Staphylococcus aureus.Cellulitis in neonates may present as sepsis, most commonly caused by group B streptococci.Hallmarks of cellulitis include the following:- Warmth, erythema, edema, and tenderness of the affected area are present.- Regional lymphadenopathy may be present.- The margin of cellulitis is not palpable. A disease similar to cellulitis, but with a sharply defined, palpable margin is erysipelas.- Fever may be present.- Cellulitis characterized by violaceous color and bullae suggests infection with Streptococcus pneumoniae (pneumococcus). Associated red streaking visible in the skin proximal to the area of cellulitis is characteristic of ascending lymphangitis.