DEFB1 and mastitis: Moreover, recent evidences indicated that the protein product of DEFB1 is detectable in human milk [62] and the mammary epithelium [63]; in particular, pregnant women display higher levels of β-defensin 1 and concentrations comparable to those observed in milk were effective in killing E. coli [62], suggesting that this antimicrobial peptide might have a fundamental role in protecting breast-fed infants from infectious diarrhea and mothers from lactational mastitis [62,63].