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McPherson AS, Whittington RJ, Hall E, Cook EJ, Jones JV, Qi Ang Y, McTavish EL, Dhungyel OP. A comparison of multivalent and bivalent vaccination strategies for the control of virulent ovine footrot. Vaccine 2021; 39:1736-1745. [PMID: 33622590 DOI: 10.1016/j.vaccine.2021.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/31/2021] [Accepted: 02/07/2021] [Indexed: 11/28/2022]
Abstract
Virulent footrot is a significant economic and animal welfare concern. The disease can be treated, controlled, and eliminated with vaccine, but selecting the appropriate vaccination strategy can be challenging. There are two main strategies: outbreak (serogroup)-specific univalent or bivalent vaccination, or use of a multivalent vaccine containing up to nine of the most common serogroups. The objective of this study was to compare these approaches in sheep flocks infected with multiple Dichelobacter nodosus serogroups. In the first phase, we undertook an immunogenicity trial in which we compared four pre-commercial multivalent recombinant fimbrial vaccines containing six (A, B, C, G, H, I) or nine (A, B, C, D, E, F, G, H, I) serogroups, and compared them to commercial bivalent vaccines. Two multivalent vaccines stimulated significantly higher antibody responses than two other multivalent vaccines but the number of serogroups included in the multivalent vaccine formulations did not have a significant effect. In the first phase, we also compared inter-vaccination intervals of two- and three-months between sequential bivalent vaccines, and found that a two-month interval was sufficient to avoid antigenic competition. In the second phase, the most immunogenic multivalent vaccine (nine serogroups) was compared to sequential bivalent vaccines and monthly foot-bathing in a field trial in four commercial Merino flocks. The duration of protection afforded by the multivalent vaccine was likely to be less than that of the bivalent vaccines, as the antibody titres stimulated were lower and less persistent.
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Affiliation(s)
- Andrew S McPherson
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Richard J Whittington
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Evelyn Hall
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Emma J Cook
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Jeremy V Jones
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Yan Qi Ang
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Emma L McTavish
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia
| | - Om P Dhungyel
- Farm Animal Health, Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Rd, Camden, New South Wales 2570, Australia.
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Petrov KK, Dicks LMT. Fusobacterium necrophorum, and not Dichelobacter nodosus, is associated with equine hoof thrush. Vet Microbiol 2013; 161:350-2. [PMID: 22909990 DOI: 10.1016/j.vetmic.2012.07.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/17/2012] [Accepted: 07/19/2012] [Indexed: 11/18/2022]
Abstract
The aim of this study was to determine which of the two species, Fusobacterium necrophorum or Dichelobacter nodosus, are associated with hoof thrush in horses. Fourteen hoof samples, collected from eight horses with thrush and 14 samples collected from eight horses with healthy hooves, were examined for the presence of F. necrophorum, Fusobacterium equinum and D. nodosus. Only isolates with phenotypic characteristics representing Fusobacterium could be cultured. Total DNA extracted from the 28 hoof samples was amplified by using DNA primers designed from gene lktA, present in F. necrophorum subsp. necrophorum, F. necrophorum subsp. funduliforme and F. equinum, and gene fimA, present in D. nodosus. The lktA gene was amplified from five of the 14 infected hoof samples and from one hoof sample without thrush. The DNA sequence of the amplified ltkA gene was identical to the lktA gene of the type strain of F. necrophorum (GenBank accession number AF312861). The isolates were phenotypically differentiated from F. equinum. No DNA was amplified using the fimA primer set, suggesting that F. necrophorum, and not D. nodosus, is associated with equine hoof thrush. Hoof thrush in horses is thus caused by F. necrophorum in the absence D. nodosus. This is different from footrot in sheep, goats, cattle and pigs, which is caused by the synergistic action of F. necrophorum and D. nodosus.
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Affiliation(s)
- Kaloyan K Petrov
- Department of Microbiology, University of Stellenbosch, Stellenbosch 7600, South Africa
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Zhou H, Hickford JG, Armstrong KF. Rapid and accurate typing of Dichelobacter nodosus using PCR amplification and reverse dot-blot hybridisation. Vet Microbiol 2001; 80:149-62. [PMID: 11295335 DOI: 10.1016/s0378-1135(00)00384-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Here we describe an approach to genotyping D. nodosus, based on variation in the fimbrial subunit gene (fimA), which uses polymerase chain reaction (PCR) amplification and hybridisation to immobilised oligonucleotides (PCR/oligotyping). The variable region of D. nodosus fimA, amplified and labelled with digoxigenin (DIG) in a single multiplex PCR amplification, was hybridised to a panel of group- and type-specific poly-dT tailed oligonucleotides that were immobilised on a nylon membrane strip. A mixture of positive control poly-dT tailed oligonucleotides was also included on the membrane. After hybridisation the membrane was washed to a defined specificity, and DIG-labelled fragments hybridising were detected with nitroblue tetrazolium (NBT) and 5-bromo-4-chloro-3-indolyl phosphate (SCIP). The specificity of the oligonucleotides was verified by the lack of cross-reactivity with D. nodosus fimA sequences that had a single base difference. DNA from 14 footrot samples previously genotyped by PCR-SSCP/sequencing [Vet. Microbiol. 71 (2000) 113], was assayed using the PCR/oligotyping technique. All types of D. nodosus which had been detected previously with a PCR-SSCP/sequencing method were detected by this procedure. However, for three of the 14 footrot samples, PCR/oligotyping detected additional types of D. nodosus. Further PCR amplification using type-specific primers, confirmed that these types of the bacterium were present in the footrot samples. These results indicate that PCR/oligotyping is a specific, accurate, and useful tool for typing footrot samples. In combination with a rapid DNA extraction protocol, D. nodosus strains present in a footrot sample can be accurately identified in less than 2 days.
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Affiliation(s)
- H Zhou
- Animal and Food Sciences Division, P.O. Box 84, Lincoln University, Lincoln, New Zealand
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Zhou H, Hickford JG. Extensive diversity in New Zealand Dichelobacter nodosus strains from infected sheep and goats. Vet Microbiol 2000; 71:113-23. [PMID: 10665539 DOI: 10.1016/s0378-1135(99)00155-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Footrot is a contagious bacterial disease of ruminants spread by the Gram-negative, anaerobic organism, Dichelobacter nodosus. It is endemic in New Zealand and throughout sheep and goat farming regions of the world. Using the polymerase chain reaction (PCR) to amplify fragments of the fimbrial gene (fimA), D. nodosus was detected in 14 hoof scrapings, sampled from six farming regions within New Zealand. DNA sequencing revealed 15 strains covering eight serogroups on the New Zealand farms. The predominant serogroup was B which contained six strains, followed by serogroups F, H and G. No strains from serogroups D and I were detected in this investigation. Eleven out of the 15 D. nodosus strains had fimbriae sequences different to those previously reported and the presence of multiple strains on a single hoof was common (86% samples). Individual sheep from the same farm, or the same paddock, were often infected by a different range of strains, which suggests a host role in mediating footrot infection.
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Affiliation(s)
- H Zhou
- Animal & Food Sciences Division, Lincoln University, New Zealand
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Pestova EV, Morrison DA. Isolation and characterization of three Streptococcus pneumoniae transformation-specific loci by use of a lacZ reporter insertion vector. J Bacteriol 1998; 180:2701-10. [PMID: 9573156 PMCID: PMC107223 DOI: 10.1128/jb.180.10.2701-2710.1998] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Although more than a dozen new proteins are produced when Streptococcus pneumoniae cells become competent for genetic transformation, only a few of the corresponding genes have been identified to date. To find genes responsible for the production of competence-specific proteins, a random lacZ transcriptional fusion library was constructed in S. pneumoniae by using the insertional lacZ reporter vector pEVP3. Screening the library for clones with competence-specific beta-galactosidase (beta-Gal) production yielded three insertion mutants with induced beta-Gal levels of about 4, 10, and 40 Miller units. In all three clones, activation of the lacZ reporter correlated with competence and depended on competence-stimulating peptide. Chromosomal loci adjacent to the integrated vector were subcloned from the insertion mutants, and their nucleotide sequences were determined. Genes at two of the loci exhibited strong similarity to parts of Bacillus subtilis com operons. One locus contained open reading frames (ORFs) homologous to the comEA and comEC genes in B. subtilis but lacked a comEB homolog. A second locus contained four ORFs with homology to the B. subtilis comG gene ORFs 1 to 4, but comG gene ORFs 5 to 7 were replaced in S. pneumoniae with an ORF encoding a protein homologous to transport ATP-binding proteins. Genes at all three loci were confirmed to be required for transformation by mutagenesis using pEVP3 for insertion duplications or an erm cassette for gene disruptions.
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Affiliation(s)
- E V Pestova
- Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60611, USA.
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Hunt JD, Jackson DC, Brown LE, Wood PR, Stewart DJ. Antigenic competition in a multivalent foot rot vaccine. Vaccine 1994; 12:457-64. [PMID: 7912871 DOI: 10.1016/0264-410x(94)90125-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The antigenic competition that occurs when pilus antigens of different serogroups are combined in multivalent vaccines for foot rot has been investigated using recombinant pilus antigens. Our prototype vaccine contains pili from nine serogroups of Dichelobacter nodosus which are expressed in Pseudomonas aeruginosa. Sheep inoculated with this multivalent vaccine were not as well protected against foot rot as those given the monovalent vaccine. Levels of agglutinating and total antibody specific for any particular pili serogroup were found to be significantly reduced in sheep vaccinated with six or more closely related pili. This effect was more pronounced for agglutinating antibody, which is thought to mediate protection, but was also observed with total antibody levels measured by ELISA. The antigenic competition was not associated with the total antigen load as a tenfold higher dose of monovalent pili induced high titres of antibody. Furthermore, distributing the vaccine to four sites, each draining to a different lymph node, failed to overcome the competition. Experiments with mixtures of monospecific sera indicate that the phenomenon is unlikely to be due to blocking of serogroup-specific protective antibodies by an excess of cross-reactive non-protective antibody elicited by heterologous pili.
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Affiliation(s)
- J D Hunt
- Department of Microbiology, University of Melbourne, Parkville, Victoria, Australia
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Billington SJ, Rood JI. Sequence of fimbrial subunit-encoding genes from virulent and benign isolates of Dichelobacter (Bacteroides) nodosus. Gene 1991; 99:115-9. [PMID: 1673665 DOI: 10.1016/0378-1119(91)90042-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Both virulent and benign isolates of the ovine pathogen Dichelobacter (Bacteroides) nodosus produce polar fimbriae which have been implicated in twitching motility. The fimbrial subunit-encoding genes from two virulent and two benign serogroup-B isolates of D. nodosus were cloned and sequenced. Analysis of the deduced amino acid (aa) sequences of these subunits indicated the presence of substitutions that appeared to correlate with the virulence phenotype. However, these aa substitutions were located in variable regions of the protein where they are unlikely to alter the functional properties of the fimbriae. The aa sequences of the serogroup-B subunits had a very high level (91-95%) of similarity, particularly at the N terminus, where the conserved region extended up to aa 61. Specific aa substitutions within the subunit of one isolate may reflect its serotypic variation from the other serogroup-B subunits studied.
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Affiliation(s)
- S J Billington
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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