What is the most common pathogen that causes mastitis?

Mastitis, particularly in breastfeeding women, is most commonly associated with Staphylococcus aureus. This pathogen is prevalent on skin and mucous membranes, making it a prime candidate for causing infections when there are any breaks in the skin or when milk stasis occurs in the breast tissues.

Staphylococcus aureus can lead to localized breast infections, marked by swelling, redness, and pain, and is often associated with the formation of an abscess. In cases of lactational mastitis, the presence of this bacterium is consistent with the the risk factors involved, such as skin colonization and nipple trauma, which can predispose women to bacterial invasion.

While other pathogens can cause mastitis, they are less frequently encountered. For instance, Escherichia coli, while it can lead to various infections, is not the primary causative organism for mastitis. Similarly, Streptococcus pneumoniae and Clostridium perfringens are associated with other types of infections and are not commonly linked to mastitis in the context of lactation. Therefore, Staphylococcus aureus stands out as the most prevalent organism in this condition.