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Campylobacter jejuni continues to be the leading cause of bacterial food-borne illness worldwide, so improvements to current methods used for bacterial detection and disease prevention are needed. We describe here the genome and proteome of C. jejuni bacteriophage NCTC 12673 and the exploitation of its receptor-binding protein for specific bacterial detection. Remarkably, the 135-kb Myoviridae genome of NCTC 12673 differs greatly from any other proteobacterial phage genome described (including C. jejuni phages CP220 and CPt10) and instead shows closest homology to the cyanobacterial T4-related myophages. The phage genome contains 172 putative open reading frames, including 12 homing endonucleases, no visible means of packaging, and a putative trans-splicing intein. The phage DNA appears to be strongly associated with a protein that interfered with PCR amplification and estimation of the phage genome mass by pulsed-field gel electrophoresis. Identification and analyses of the receptor-binding protein (Gp48) revealed features common to the Salmonella enterica P22 phage tailspike protein, including the ability to specifically recognize a host organism. Bacteriophage receptor-binding proteins may offer promising alternatives for use in pathogen detection platforms.Campylobacter belongs to the epsilon class of proteobacteria and is the leading cause of bacterial food-borne gastroenteritis worldwide (22). Campylobacter has also been associated with severe neurological disorders such as the Guillain-Barré and Miller-Fisher syndromes, as well as reactive arthritis and irritable bowel syndrome (32). Many Campylobacter phages have been characterized by their host-range characteristics, morphology, genome size, and susceptibility to restriction endonucleases (5,7,24). Only a few of the characterized Campylobacter phages are members of the B1 group of the family Siphoviridae (1), while most belong to the family Myoviridae possessing genomes which fall into three size classes: 110 to 150 kb (class III), 170 to 190 kb (class II), and 320 kb (class I) (24). One interesting characteristic of many of these phages is that their DNA appears to be resistant to cleavage by several common restriction endonucleases, thus making them "refractory to genomic analysis" (34). Two genomes of Campylobacter phages have been sequenced thus far: CPt10 and CP220 (34). Both appear to be closely related to each other and belong to the class II of Campylobacter Myoviridae phage genomes (34).Bacteriophages possess enormous diagnostic and therapeutic potential, which provides promise for the development of a wide range of novel antimicrobials and diagnostic tools (14). Numerous phages have been isolated against Campylobacter for use in phage typing schemes (9,10,12,18,25), but it has only recently been shown that bacteriophages can effectively decrease Campylobacter contamination (4, 20, 36). For example, Campylobacter-specific phages were able to reduce the numbers of Campylobacter coli and Campylobacter jejuni in chickens when added directly to the...

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.