Lactoferrin inhibits E. coli O157:H7 growth and attachment to intestinal epithelial cells

Abstract

ABSTRACT:Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 strains are associated with haemorraghic colitis and haemolytic uremic syndrome (HUS) in humans. Cattle are a reservoir of E. coli O157:H7. We studied the ability of bovine and human lactoferrin, two natural antimicrobial proteins present in milk, to inhibit E. coli O157:H7 growth and attachment to a human epithelial colorectal adenocarcinoma cell line (Caco-2). The direct antibacterial effect of bLF on E. coli O157:H7 was stronger than that of hLF. Nevertheless, both lactoferrins had bacteriostatic effects even at high concentrations (10 mg/ml), suggesting blocking of LF activity by a yet undefined bacterial defence mechanism. Additionally, both lactoferrins significantly inhibited E. coli O157:H7 attachment to Caco-2 cells. However, hLF was more effective than bLF, probably due to more efficient binding of bLF to intelectin present on human enterocytes leading to uptake and thus removal of bLF from the extracellular environment. Inhibition of bacterial attachment to Caco-2 cells was at least partly due to the catalytic effect of lactoferrins on the type III secreted proteins EspA and EspB

Effects of adding poly-histidine tag on stability, antimicrobial activity and safety of recombinant buforin I expressed in periplasmic space of Escherichia coli

“…Strategies for improving antimicrobial peptide production discussed by Deo et al 17 , are summarized in Table 4. Periplasmic expression of proteins has several important advantages over intracellular expression: (1) toxic or lethal effects of some target proteins can be reduced or eliminated through periplasmic expression; (2) by expressed periplasmically or extracellularly, target proteins can become more solubilized ; (3) an unwanted primary methionine in a protein sequence that it would not normally contain can be prevented by using signal www.nature.com/scientificreports/ peptides in periplasmic or extracellular expression; and (4) protein secretion in the periplasmic environment facilitates the process of downstream processes 18,19 .…”

Lactoferrin and lysozyme to reduce environmental enteric dysfunction and stunting in Malawian children: study protocol for a randomized controlled trial

“…Bovine lactoferrin has been granted Generally Regarded as Safe (GRAS) status by the US Food and Drug Administration, and is widely used in studies of lactoferrin efficacy [ 23 , 47 , 48 ]. It will be acquired from FrieslandCampina (Amersfoort, Netherlands).…”

Functional stirred Yoghurt fortified with buffalo, bovine, mix colostrum and lactoferrin, effect of lactoferrin on pathogenic bacteria and amino acids of buffalo, bovine colostrum and lactoferrin

“…MIC for E. coli, P. aeruginosa and S. typhi were 2.3, 1 and 0.8 respectively. Although lactoferrin is effective on both gram positive and gram-negative bacteria, it had a greater effect on the gram-positive bacteria.The main reason for greater effect of the lactoferrin on grampositive bacteria than gram-negative might be the protective role of the gram-negative membrane's outer membrane, which acts as an effective barrier, is to blame [47,48].Another reason is that gram-positive bacteria have a single membrane, which renders them more accessible to permeation by lactoferrin. The MIC and MBC of several types of lactoferrin have been examined in multiple research.…”