Impetigo contagiosa is caused by

Impetigo is caused by Streptococcus pyogenes belonging to a limited number of serotypes, usually high numbered M types, instead of the lower numbered M types which cause throat infection. Impetigo and streptococcal infection of scabies is the main cause of acute glomerulonephritis in children in tropics. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 215