Clearance of Escherichia coli O157:H7 Infection in Calves by Rectal Administration of Bovine Lactoferrin

Abstract

dEnterohemorrhagic Escherichia coli (EHEC) strains, of which E. coli O157:H7 is the best-studied serotype, are an important group of foodborne pathogens causing severe illness in humans worldwide. The main reservoirs for EHEC are ruminants, mostly cattle, which harbor the bacteria in their intestinal tracts without showing clinical symptoms. In this study, we used bovine lactoferrin, a natural occurring bactericidal and immunomodulating protein, as an antibacterial agent against EHEC infection in cattle. Nine 3-month-old Holstein-Friesian calves were experimentally infected with EHEC (strain NCTC12900). Three animals received a daily rectal spray treatment with bovine lactoferrin, three animals received an oral treatment, and three animals served as a control group. Blood samples were collected weekly and fecal samples twice weekly to monitor antibody responses and fecal excretion, respectively. Animals in the rectal group ceased shedding within 26 days of the experimental treatment and remained negative. This beneficial effect of bovine lactoferrin was not observed in the oral group, where animals were still shedding at the time of euthanasia (day 61). All groups developed serum responses, but no clear differences could be observed between the groups. However, the results indicate that the use of bovine lactoferrin as a rectal treatment can be a useful strategy to preclude further transmission of EHEC infections from cattle to humans.

An Overview of the Elusive Passenger in the Gastrointestinal Tract of Cattle: The Shiga Toxin Producing Escherichia coli

“…Various feed and water additives, such as orange, citrus peel and pulp and tannin extracts, have reported positive results in controlling E. coli O157:H7 in cattle [ 48 ]. Lactoferrin, an iron-binding glycoprotein that exhibits antibacterial activity, can eliminate E. coli O157:H7 shedding if administered by rectal injection but not orally [ 179 ]. However, most of these results originate from small trials and single studies, and therefore, extensive testing is required to verify their potential anti-O157:H7 properties and examine their impact on the rest of the microbiota (since many antimicrobials are wide range) [ 19 , 48 ].…”

Potential immunosuppressive effects of Escherichia coli O157:H7 experimental infection on the bovine host

“…Six animals were inoculated at the age of 6 weeks with 10 10  CFU during two consecutive days as previously described by Kieckens et al [17]. Two weeks after infection, three animals were euthanized (Infection Group, IG).…”

The Role of Escherichia coli Shiga Toxins in STEC Colonization of Cattle

“…bLF is internalized by bovine rectal epithelial cells and becomes translocated to the nuclei, in particular when cells are co-cultured with E. coli O157:H7 [221]. bLF mitigates shedding of E. coli O157:H7 by cattle [222], but only if applied rectally, i.e., at the principal colonization site of bacteria of this serotype [222]. Treatment approaches such as monoclonal antibodies or antisera directed against Stxs and toxin receptor analogs, developed for the treatment of human STEC infections [16] have not been tested for their efficacy to protect cattle against the immunmodulatory effects of Stxs but will likely remain too expensive to be considered for such use.…”