Prevalence of bacteria in the nipple discharge of patients with duct ectasia.

The aim of this study was to identify the aerobic and the anaerobic microorganisms which can be related to duct ectasia. The patients were divided into two groups. Group 1 comprised 100 patients with coloured nipple discharge (duct ectasia group), and Group 2 (the control group) was composed of 50 patients without nipple discharge. The culture media used were BHI-PRAS, blood agar, mannitol agar and MacConkey agar. There was a high frequency of bacterial growth in the two groups: 85% in Group 1 and 88% in Group 2. The most prevalent bacteria were Staphylococcus aureus and Staphylococcus epidermidis. There was a statistically significant higher rate of smokers in the duct ectasia group compared with the control group, 25 (25%) patients vs. 5 (10%), respectively (p = 0.03). These findings allow us to put forth the hypothesis that the genesis of duct ectasia may be a non-infectious inflammatory process.