SUMMARYThis literature review cross-contaminationevidence of periodontal pathogens, specificallyAggregatibacter actinomycetemcomitansbetween members of the same family,which includes spouses and children, aswell as to identify the more importanttransmission routes. Describing the possibleroutes of transmission of periodontalbacteria could lead to methods to preventor reduce microbial cross-contaminationbetween family members and possiblyreduce disease transmission.Key words: Periodontitis, microbiology,transmission, Aggregatibacter actinomycetemcomitans.