2.2 Definitions
The definition of mastitis was adopted with widely accepted criteria: the presence of inflammatory characteristics including localized redness, swelling, heat and pain in the breast accompanied by a temperature of 38.5oC or greater, chills, flu-like aches, and systemic illness.11 Treatment outcomes were extracted from the medical records. Treatment failures were determined when there were any of the following situations: (1) deterioration of signs or symptoms; (2) an emerging breast abscess; or (3) switching to a new antibiotic or changing the initial antibiotic. SLCs from routine blood tests were collected at first presentation, and patients were classified into three groups based on the levels of leukocyte counts: 31 patients had a normal leukocyte count (NLC, <1.0×10^9 cells/L); 111 patients had a slightly elevated leukocyte count (SELC, 1.0-1.5×10^9 cells/L); and 156 patients had a markedly elevated leukocyte count (MELC, >1.5×10^9 cells/L). Patients were further divided into subgroups according to the use of antibiotics. The number of patients in the NLC group was small; therefore, in the current study, we explored the value of SLCs in patients with elevated leukocyte counts, including patients with SELCs and MELCs.