Mastitis

PATHOGENS

• Noninfectious causes
• Staphylococcus aureus including MRSA
• Coagulase-negative Staphylococci
• Corynebacterium spp. (role in disease uncertain but consider in granulomatous inflammatory mastitis)
  
  • C. kroppenstedtii
    • Clinical isolates of this organism have been almost entirely reported in women with breast abscesses and/or granulomatous mastitis.
  • C. amycolatum
  • C. tuberculostearicum
• Streptococcal species (e.g, Streptococcus mitis)
• Peptostreptococcus
• Prevotella species
• Bacteroides species
• Mycobacterium tuberculosis (endemic regions especially, TB mastitis generally rare but may be up to 4% of TB presentations in India)
• In patients with a history of recurrent breast abscesses, up to 20% have mixed flora.