Etiology of Abscesses Numerous organisms can cause abscesses, but the most common is Staphylococcus aureus Organisms may enter the tissue by Direct implantation (eg, penetrating trauma with a contaminated object) Spread from an established, contiguous infection Dissemination via lymphatic or hematogenous routes from a distant site Migration from a location where there are resident flora into an adjacent, normally sterile area because natural barriers are disrupted (eg, by perforation of an abdominal viscus causing an intra-abdominal abscess) Abscesses may begin in an area of cellulitis or in compromised tissue where leukocytes accumulate.