Live-Attenuated Oral Vaccines to Reduce Campylobacter Colonization in Poultry

Abstract

The control of Campylobacter in poultry at the pre-harvest level is critical to reducing foodborne infections with Campylobacter since the consumption of contaminated poultry is the most frequent cause of human campylobacteriosis. Although poultry vaccination is suggested as useful intervention measures, no Campylobacter vaccines are currently available. To develop live-attenuated oral Campylobacter vaccines, in this study, we evaluated the efficacy of pre-colonization by oxidative stress defense mutants, including knockout mutants of ahpC, katA, and sodB, in preventing Campylobacter jejuni from colonizing poultry. Interestingly, when chickens were pre-colonized with ΔahpC and ΔkatA mutants, rather than the ΔsodB mutant, the level of C. jejuni colonization was significantly reduced within 35 days. Further studies demonstrated when chickens were pre-colonized with the ΔahpC mutant by oral challenge with a high dose (ca., 5 × 108 CFU/bird) and a low dose (ca., 5 × 106 CFU/bird), it twice reduced the level of C. jejuni by 3.9 log10CFU/g feces and 3 log10CFU/g feces after 42 days, respectively, compared to the untreated control. Due to a colonization defect, the ΔahpC mutant was removed from chickens within 42 days. After excretion from the host, moreover, the ΔahpC mutant cannot survive in aerobic environments because of compromised aerotolerance. Our findings suggest that the ahpC mutant has a great potential for on-farm application to control C. jejuni at the pre-harvest level.

Genomic tailoring of autogenous poultry vaccines to reduceCampylobacterfrom farm to fork

“…Consistent with the population manipulation approach, live-attenuated oral vaccines can also be tailored to target high-risk aerotolerant isolates as in mutagenesis studies 60 . Vaccine design was informed by prior knowledge of the genes linked to survival through poultry production 41 , and included a single isolate from each of the four pre-vaccination lineages with the highest predicted survivability.…”

“…Known survival-associated genetic elements were identified in C. jejuni genomes from unvaccinated chickens (S4 (n = 65), CC443 (n = 60), CC206 (n = 66), ST-4430 (n = 61). The number of survival-associated elements also varied within CCs: CC257 (51-67), CC443 (52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63), CC206 (47-68), ST-4430 (46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63).…”

Evaluation of Two Recombinant Protein-Based Vaccine Regimens against Campylobacter jejuni: Impact on Protection, Humoral Immune Responses and Gut Microbiota in Broilers

“…However, despite promising results, there is currently no efficient strategy for reducing Campylobacter's colonisation of the avian gut. One of the promising strategies is the vaccination of broilers, and several vaccination strategies have been investigated in recent decades [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. While initial studies used whole-cell vaccines, more recent studies have tested subunit vaccines.…”

Plasmid DNA Prime/Protein Boost Vaccination against Campylobacter jejuni in Broilers: Impact of Vaccine Candidates on Immune Responses and Gut Microbiota

“…Moreover, different routes of administration (intramuscular, oral, and in ovo) have been tested. However, these studies have produced inconsistent results on intestinal Campylobacter loads in poultry [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]; consequently, no effective vaccine is available to date.…”