Initial skin cultures yielded 100% recovery of group A streptococci from the lesions of 66 patients suffering from ecthymatous impetigo. Of the 66 patients, 85% also had coagulase-positive staphylococci in their lesions with 45% of the staphylococci resistant to penicillin G.
Patients were divided into two treatment groups. The first treatment group (30 patients) received 600,000 units of benzathine penicillin G intramuscularly in a single injection; whereas the second treatment group (36 patients) received 600,000 units of procaine penicillin G intramuscularly in a single injection. All patients receiving benzathine penicillin G showed complete healing within a week, whereas only 38% receiving procaine penicillin G healed within two weeks.
Kelly C, Taplin D, Allen AM. Streptococcal EcthymaTreatment With Benzathine Pencillin G. Arch Dermatol. 1971;103(3):306-310. doi:10.1001/archderm.1971.04000150076011