A 2-year-old is suspected of having cellulitis of the finger. Which organism or condition is the most likely cause of the infection?

Rationale: A. Parainfluenza virus typically causes respiratory illnesses like croup, not skin infections. B. Respiratory syncytial virus (RSV) primarily affects the lower respiratory tract in infants and young children and is unrelated to skin infections. C. Escherichia coli is more commonly associated with gastrointestinal and urinary tract infections, not skin infections. D. Streptococcus species, particularly Streptococcus pyogenes (Group A strep), are a common cause of cellulitis, especially in children. The infection often enters through breaks in the skin, leading to inflammation and infection of the deeper dermis and subcutaneous tissue.