Porcine and Bovine Forms of Lactoferrin Inhibit Growth of Porcine Enterotoxigenic Escherichia coli and Degrade Its Virulence Factors

Abstract

<jats:p>Post-weaning diarrhoea (PWD) is an economically important, multifactorial disease affecting pigs within the first two weeks after weaning. The most common agent associated with PWD is enterotoxigenic <jats:italic>E. coli</jats:italic> (ETEC). Currently, antibiotics are used to control PWD and this has most likely contributed to an increased prevalence of antibiotic resistant strains. This puts pressure on veterinarians and farmers to decrease or even abandon the use of antibiotics, but these measures need to be supported by alternative strategies for controlling these infections. Natural derived molecules, such as lactoferrin, could be potential candidates due to their antibacterial or immune modulating activities. Here, we analyzed the ability of bovine lactoferrin (bLF), porcine lactoferrin (pLF) and ovotransferrin (ovoTF) to inhibit ETEC growth, degrade ETEC virulence factors and inhibit adherence of these pathogens to porcine intestinal epithelial cells. Our results revealed that bLF and pLF, but not ovoTF, inhibit the growth of ETEC. Furthermore, bLF and pLF can degrade several virulence factors produced by ETEC strains, more specifically F4 fimbriae, F18 fimbriae and flagellin. On the other hand, ovoTF is able to degrade F18 fimbriae and flagellin, but not F4 fimbriae. An <jats:italic>in vitro</jats:italic> adhesion assay showed that bLF, ovoTF and pLF can decrease the number of adherent bacteria to epithelial cells. Our findings demonstrate that lactoferrin can directly affect porcine ETEC strains, which could allow lactoferrin to serve as alternative for antimicrobials to prevent ETEC infections in piglets.</jats:p> <jats:p><jats:bold>IMPORTANCE</jats:bold> Currently, post-weaning F4<jats:sup>+</jats:sup> and F18<jats:sup>+</jats:sup> <jats:italic>E. coli</jats:italic> infections in piglets are controlled by the use of antibiotics and zinc-oxide, but the use of these antimicrobial agents most likely contributes to the increase in antibiotic resistance. Our work demonstrates that bovine and porcine lactoferrin can inhibit the bacterial growth of porcine enterotoxigenic <jats:italic>E. coli</jats:italic> strains. In addition, we also show that lactoferrin can reduce the adherence of these strains to small intestinal epithelial cells, even at a concentration that does not inhibit bacterial growth. This research could allow us to develop lactoferrin as an alternative strategy to prevent ETEC infections in piglets.</jats:p>

A bovine lactoferricin-lactoferrampin-encoding Lactobacillus reuteri CO21 regulates the intestinal mucosal immunity and enhances the protection of piglets against enterotoxigenic Escherichia coli K88 challenge

“…16,17 In this sense, AMPs serves as a strategy to provide protection against ETEC colonization and infection. 18 Despite an obvious clinical need, there are a number of barriers to the study of gut function and immune regulation. Studies on human infants with intestinal diseases continue to unavoidably suffer from the limitations of fecal analysis and remain confounded by variables with recognized impact on the intestinal bacterial community composition including differences in mode of delivery, gestational age, type of enteral nutrition, concurrent disease and treatment with antibiotics.…”

Transferrins Reduce Replication of Chlamydia suis in McCoy Cells

“…However, this can only be proven by using the identical experimental conditions used by Beeckman et al [ 38 ]. Therefore, a batch of recombinant porcine LF is currently being produced, as described by Dierick et al [ 33 ], to examine this hypothesis in depth by using the previously described method [ 38 ]. We already used this recombinant porcine LF (pLF) successfully in in vitro studies with porcine enterotoxigenic Escherichia coli [ 33 ].…”

“…Therefore, a batch of recombinant porcine LF is currently being produced, as described by Dierick et al [ 33 ], to examine this hypothesis in depth by using the previously described method [ 38 ]. We already used this recombinant porcine LF (pLF) successfully in in vitro studies with porcine enterotoxigenic Escherichia coli [ 33 ]. However, recombinant pLF is much more expensive compared to ovoTF or bLF, and thus less attractive for use in the pig industry.…”

“…Lactoferrin not only binds endotoxins (LPS), it also influences the release and bioactivity of Shiga toxins from enterohemorrhagic Escherichia coli O157:H7 (EHEC) strains [ 32 ], and it degrades F4 fimbriae, F18 fimbriae and flagellin of porcine EHEC strains. Lactoferrin can also decrease the number of adherent bacteria to porcine small intestinal epithelial cells [ 33 ].…”

“…This bactericidal activity can be attributed to the amino-terminal N-lobe of ovoTF from which the cationic antimicrobial peptide OTAP-92, consisting of 92 amino acids, was derived. Ovotransferrin degrades F18 fimbriae and flagellin, but not F4 fimbriae of porcine EHEC strains, and decreases the number of adherent bacteria to porcine small intestinal epithelial cells [ 33 ].…”