β-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria
Journal Title: Jornal de Pediatria - Year 2015, Vol 91, Issue 1
Abstract
Objective To describe the antimicrobial activity of β-defensin-2 produced in the mammary gland and secreted in human breast milk. Methods The peptide production was performed by DNA cloning. β-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA). Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of β-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test. Results The peptide levels were higher in colostrum (n=61) than in mature milk samples (n=39), as follows: median and range, 8.52 (2.6-16.3) μg/ml versus 0.97 (0.22-3.78), p<0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1–4μg, which produced inhibition zones ranging from 18 to 30mm against three isolates of Salmonella spp. and four of E. coli. β-defensin-2 showed minimum inhibitory concentrations (MICs) of 0.25μg/mL and 0.5μg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4μg/mL) was obtained against an isolated of multidrug-resistant strain of A. baumannii. Conclusions To the authors’ knowledge, this study is the first to report β-defensin-2 levels in Latin American women. The production and the activity of β-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients.
Authors and Affiliations
Luz Thomas
Keywords
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- EP ID EP561118
- DOI 10.1016/j.jped.2014.05.006
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