Primary Isolation Strain Determines Both Phage Type and Receptors Recognised by Campylobacter jejuni Bacteriophages

Abstract

In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated using NCTC12662 as the indicator strain, which may have biased the selection of phages. A large group of C. jejuni phages rely on the highly diverse capsular polysaccharide (CPS) for infection and recent work identified the O-methyl phosphoramidate modification (MeOPN) of CPS as a phage receptor. We therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb), host range and morphological appearance correlated with the isolation strain. Thus, according to C. jejuni phage grouping, NCTC12662 and NCTC12658 selected for CP81-type phages, while RM1221 selected for CP220-type phages. Furthermore, using acapsular ∆kpsM mutants we demonstrated that phages isolated on NCTC12658 and NCTC12662 were dependent on the capsule for infection. In contrast, CP220-type phages isolated on RM1221 were unable to infect non-motile ∆motA mutants, hence requiring motility for successful infection. Hence, the primary phage isolation strain determines both phage type (CP81 or CP220) as well as receptors (CPS or flagella) recognised by the isolated phages.

Campylobacter spp. and bacteriophages from broiler chickens: Characterization of antibiotic susceptibility profiles and lytic bacteriophages

“…Most bacteriophages exhibiting specificity for Campylobacter bacteria have a structure typical of phages of the family Myoviridae (Hansen et al, ; Hwang et al, ; Sorensen et al, ). In the present study, however, in addition to the phages assigned to the Myoviridae family, we also obtained phages which were assigned to the Siphoviridae family on the basis of their morphological structure.…”

FlhF(T368A) modulates motility in the bacteriophage carrier state of Campylobacter jejuni

“…Surface structures are candidates for adhesion targets and receptors necessary for bacteriophage infection. In C. jejuni, flagella and capsular polysaccharide have been proposed to constitute essential attachment sites for the respective infection of group II and group III Campylobacter phages (Rakhuba et al, 2010;Sørensen et al, 2015). Group II phages CP220, Φ3 and Φ15 failed to infect non-flagellated strains that included the largely non-flagellated flhF(T368A) expressing strain.…”

A Flagellar Glycan-Specific Protein Encoded by Campylobacter Phages Inhibits Host Cell Growth

“…Furthermore, we have shown that homologues of this protein exist in all sequenced campylobacter phages and that homologues that we tested are also capable of binding to the same sugar residues [ 16 ]. These observations were notable considering that many C. jejuni phages, including NCTC 12673, recognize the phase-variable capsular polysaccharides and exhibit limited host ranges with high rates of resistance development [ 17 , 30 ]. In addition, it is well known that the 9-carbon sugar known as pseudaminic acid is essential for flagellar filament assembly and thus for bacterial motility and virulence.…”