Orally Administered P22 Phage Tailspike Protein Reduces Salmonella Colonization in Chickens: Prospects of a Novel Therapy against Bacterial Infections

Abstract

One of the major causes of morbidity and mortality in man and economically important animals is bacterial infections of the gastrointestinal (GI) tract. The emergence of difficult-to-treat infections, primarily caused by antibiotic resistant bacteria, demands for alternatives to antibiotic therapy. Currently, one of the emerging therapeutic alternatives is the use of lytic bacteriophages. In an effort to exploit the target specificity and therapeutic potential of bacteriophages, we examined the utility of bacteriophage tailspike proteins (Tsps). Among the best-characterized Tsps is that from the Podoviridae P22 bacteriophage, which recognizes the lipopolysaccharides of Salmonella enterica serovar Typhimurium. In this study, we utilized a truncated, functionally equivalent version of the P22 tailspike protein, P22sTsp, as a prototype to demonstrate the therapeutic potential of Tsps in the GI tract of chickens. Bacterial agglutination assays showed that P22sTsp was capable of agglutinating S. Typhimurium at levels similar to antibodies and incubating the Tsp with chicken GI fluids showed no proteolytic activity against the Tsp. Testing P22sTsp against the three major GI proteases showed that P22sTsp was resistant to trypsin and partially to chymotrypsin, but sensitive to pepsin. However, in formulated form for oral administration, P22sTsp was resistant to all three proteases. When administered orally to chickens, P22sTsp significantly reduced Salmonella colonization in the gut and its further penetration into internal organs. In in vitro assays, P22sTsp effectively retarded Salmonella motility, a factor implicated in bacterial colonization and invasion, suggesting that the in vivo decolonization ability of P22sTsp may, at least in part, be due to its ability to interfere with motility… Our findings show promise in terms of opening novel Tsp-based oral therapeutic approaches against bacterial infections in production animals and potentially in humans.

Modified Bacteriophage S16 Long Tail Fiber Proteins for Rapid and Specific Immobilization and Detection of Salmonella Cells

“…The use of affinity-based magnetic separation can simultaneously tackle two critical parameters to reduce detection assay time and increase sensitivity, by (i) enriching viable cell numbers to a detectable level and (ii) isolating cells from contaminants and debris found in food samples for more accurate downstream identification and characterization (51). Toward our aim to develop a sensitive and specific assay for bacterial enrichment that can outcompete the conventional application of antibodies for biomolecular recognition, the bacteriophage S16 LTF joins other approaches employing either whole phages (25,32,33,58,59) or phage-encoded proteins, such as endolysin cell wall-binding domains (CBDs) (36)(37)(38) and tail spike RBPs (39)(40)(41).…”

“…Previously, the tail spike RBP from phage P22 has been developed as a probe for detecting Salmonella in real-time biosensors (39) and, due to its inherent enzymatic activity, as a treatment against Salmonella colonization in chickens (40). Campylobacter phage RBPs have also been developed as probes for detecting the organism via surface plasmon resonance (SPR) biosensors (41), as well as for a cell agglutination assay (42).…”

N-Glycosylation of Campylobacter jejuni Surface Proteins Promotes Bacterial Fitness

“…Chickens were obtained from the Poultry Research Facility, Department of Agriculture, Food and Nutritional Science, University of Alberta. Chicken cecal contents (CCC) were harvested from 1-and 5-week-old leghorn chickens, which were confirmed to be free of C. jejuni, as described by Waseh et al (18). Briefly, chicken ceca were excised, and the contents were collected in Eppendorf tubes from euthanized birds.…”

Antimicrobial bacteriophage-derived proteins and therapeutic applications

“…114,115 Examples are endorhamnosidases that hydrolyze outer membrane LPS of Gram-negative species, 116 endolsialidases that degrade capsular polysaccharides of E. coli, 113 alginate lysases that degrade the capsules of P. aeruginosa, 117 and hyaluronidases that degrade capsules of streptococcal species. 113 To the best of our knowledge, polysaccharide depolymerases have not been shown to be bacteriolytic or bacteriostatic.…”

“…The mode of action of P22sTsp in reducing Salmonella colonization is uncertain, but may be attributed to its endorhamnosidase activity and/or binding activity of O-antigen in LPS, thus compromising cell surface structures. 116 The theory that removing the bacterial EPS can reduce the pathogen's ability to colonize and cause disease was tested by removing the EPS layer of the plant pathogen Erwinia amylovora. 123,124 Erwinia spp.…”