“…According to the literature, all leukotoxic strains comprise a single clone and are particularly abundant in Africans and their descendants 16,28,32 , such as were the members of the family reported here. In this population, the distribution might be closely related to cultural aspects and contacts among relatives 32 . In the present case of aggressive periodontitis and her relatives, however, only the patient and her sister were colonized with highly leukotoxic bacteria, a fact suggesting another source for this microorganism.…”