Activity againstListeria monocytogenesof human milk during lactation. A preliminary study

Abstract

Human milk samples from three healthy donors were investigated in order to evaluate the antibacterial activity during lactation against Escherichia coli ATCC 25922 and Listeria monocytogenes. The concentration of the main human-milk antimicrobial proteins (lactoferrin (LF), lysozyme (LZ) and secretory immunoglobulin A (sIgA)) was determined by ELISA. Results showed that human milk exhibited antibacterial activity against List. monocytogenes, although it was weakly active against Esch. coli ATCC 25922. The observed antilisterial activity was positively correlated with LZ concentration. In addition, the effect of gastrointestinal proteases, at different pH conditions, that prevail in the stomach of infants (pH 2.0-6.5), on antilisterial activity and protein degradation was evaluated. Hydrolysis with pepsin at pH 4.0-6.5, followed by treatment with pancreatic enzymes, resulted in a decreased hydrolysis of LZ, LF and sIgA and an enhanced antibacterial activity against List. monocytogenes. It is suggested that partial degradation of certain milk proteins at the gastrointestinal level may produce peptides that could act synergistically with the remnant intact proteins.

Effect of the vitamin B12-binding protein haptocorrin present in human milk on a panel of commensal and pathogenic bacteria

“…For the latter three, this is consistent with the findings of Lopez-Exposito and coworkers, who ascribed the inhibitory effect to the lysozyme in human milk, possibly in combination with lactoferrin/immunoglobulin A [28]. We were surprised to see an inhibitory effect of human milk on S. thermophilus , as this species is widely used in the dairy industry [29], but also this is likely to be attributed to lysozyme/lactoferrin/immunoglobulin A or other antibacterial proteins in human milk [30].…”

Lactoferrin in the Prevention and Treatment of Intestinal Inflammatory Pathologies Associated with Colorectal Cancer Development

“…Several studies showed that Lf is capable of exerting anti-microbial activity against these bacteria [36,180,[211][212][213][214]. Indeed, in vitro studies have demonstrated that Lf acts against P. aeruginosa planktonic and biofilm-forming cells by depriving the environment of iron, thus reducing bacterial growth and colonization, and by permeabilizing bacterial membranes thus leading to bacterial lysis [36,212,214,215].…”

Inhibition Kinetics of Sesamol Against Lactoperoxidase System

“…Laktoperoksidaz, lizozim ve laktoferrin gibi birçok süt proteini hem yeni doğanlarda hem de yetişkinlerde sağlığın korunması için önemlidir. 19 Sütteki laktoperoksidaz sisteminin antibakteriyel etkisi, SCNiyonlarının H2O2 varlığında katalizlenen reaksiyonu sonucu oluşan ürünlere dayanır. 20 Tiyosiyanatın oksidasyonu sırasında oluşan aktif ara ürünün hipotiyosiyanat olduğu kabul edilir.…”