Staphylococcus aureus is the most common cause of mastitis because it has the ability to colonize the skin and nipple ducts, leading to infection especially during breastfeeding. Its production of toxins and enzymes facilitates tissue invasion and abscess formation. Its knack for adherence and evasion of host defenses makes it a frequent pathogen in both acute and chronic mastitis cases. Early identification and targeted antibiotic treatment are crucial to prevent complications such as abscess development.

Reference: Sabiston Textbook of Surgery, Courtney M. Townsend Jr., 21st Edition.