If one of the following conditions is met, the diagnosis of acute lactational mastitis is made: localized redness of the breast, with or without elevated temperature; systemic inflammatory response, such as chills, headache, and fatigue; body temperature higher than 37.3°C or elevated WBC or neutrophil counts or CRP levels; patients with positive milk cultures.[13] The pathogenic bacteria of mastitis involve S aureus, Streptococcus, and/or Bacillus, with the most common being S aureus and S epidermidis. The gene discussed is CRP; the disease is mastitis.