Campylobacter jejuni Developed the Resistance to Bacteriophage CP39 by Phase Variable Expression of 06875 Encoding the CGPTase

Abstract

Bacteriophage (phage) is regarded as an antimicrobial alternative for Campylobacter in food production. However, the development of phage resistance to the host is a main concern for the phage application. This study characterized the phage CP39 and investigated the phage resistance of CP39 in Campylobacter jejuni NCTC12662. We determined that phage CP39 belonged to the Myoviridae family by the WGS and phylogenetic analysis. Phage CP39 was confirmed as a capsular polysaccharide (CPS)-dependent phage by primary C. jejuni phage typing. It was further confirmed that the phage could not be adsorbed by the acapsular mutant ΔkpsM but showed the same lytic ability in both the wild-type strain NCTC 12662 and the ΔmotA mutant lacking motile flagella filaments. We further determined that the 06875 gene encoding CDP-glycerol:poly (glycerophosphate) glycerophosphotransferase (CGPTase) in the CPS loci was related to phage CP39 adsorption by SNP analysis and observed a rapid development of phage resistance in NCTC 12662 during the phage infection. Furthermore, we observed a high mutation frequency of 06875 (32%), which randomly occurred in nine different sites in the gene according to colony PCR sequencing. The mutation of the 06875 gene could cause the phase variable expression of non-functional protein and allow the bacteria against the phage infection by modifying the CPS. Our study confirmed the 06875 gene responsible for the CPS-phage adsorption for the first time and demonstrated the phase variable expression as a main mechanism for the bacteria to defend phage CP39. Our study provided knowledge for the evolutionary adaption of bacteria against the bacteriophage, which could add more information to understand the phage resistance mechanism before applying in the industry.

The trade-off of Vibrio parahaemolyticus between bacteriophage resistance and growth competitiveness

“…For bacteriophage therapy, it is necessary to solve the development of bacteriophage resistance to the host. However, the mechanism of bacteriophage resistance is rarely reported, we lack detailed knowledge about their ecological and evolutionary interactions ( Kortright et al, 2019 ; Markwitz et al, 2021 ; North and Brown, 2021 ; Tang et al, 2022 ).…”

Intervention Strategies to Control Campylobacter at Different Stages of the Food Chain

“…Bacteriophages are “viruses that can infect and kill targeted bacterial cells” [ 166 ]. They have been extensively researched and used as antimicrobial agents worldwide for the treatment of several human diseases and recently as preventative and therapeutic agents to control Campylobacter colonization in poultry [ 167 , 168 , 169 , 170 , 171 , 172 ]. In a recent study, oral administration of two field bacteriophages to experimentally infected broiler chickens at 37 days of age significantly reduced Campylobacter counts by 2 log 10 CFU/g at 40 days of age [ 168 ].…”

“…However, phage cocktails must be carefully designed based on the types of phages being administered to achieve maximal benefits as phages exhibit different mechanisms of infection. For example, group 2 phages isolated from C. jejuni RM1221 typically use flagella as a route of entry, while group 3 phages isolated from C. jejuni NCTC12662 target bacterial capsular polysaccharide receptors [ 171 , 173 ]. In this context, Hammer et al [ 174 ] have demonstrated that administration of a group 3 phage CP14 alone reduced fecal counts by 1 log 10 , while when co-administered with CP81, which belongs to the same group, no further reduction in fecal Campylobacter count was observed.…”

Despite Shared Geography, Campylobacter Isolated from Surface Water Are Genetically Distinct from Campylobacter Isolated from Chickens

“…The lack of homogenization of the species may be due to the existence of subpopulation-specific barriers to genetic exchange. A multitude of mechanisms exist that prevent entry of foreign DNA into the bacteria, such as variation of capsular polysaccharides or of flagellar structures ( 8 , 9 ). Two powerful barriers for genetic exchange after the DNA has entered the cell include clustered regularly interspaced palindromic repeat (CRISPR)-directed nucleases that can destroy DNA carrying a specifically recognized sequence ( 10 – 13 ) and restriction/modification systems ( 14 , 15 ).…”