Does a particular pathogen cause impetigo?

Yes. Impetigo is caused by one of two bacteria-staphlococcus or streptococcus. It is contagious to others. It is either treated with a cream or antibiotic pills depending on how bad it is.
Strep and or staph. Impetigo is caused by gram positive bacteria predominately by streptococcus. Localized cases are treated with muprocin cream or ointment. More extensive cases will require oral antibiotics.