Characterisation of Erysipelothrix rhusiopathiae isolates from pigs associated with vaccine breakdowns

• Published in: Veterinary microbiology 2006-07, Vol.115 (4), p.329-338
• Main Authors: Eamens, G.J., Forbes, W.A., Djordjevic, S.P.
• Format: Article
• Language: English
• Subjects: Animals; Applied microbiology; Australia - epidemiology; Bacterial Vaccines - immunology; Bacteriology; Biological and medical sciences; DNA, Bacterial - analysis; Erysipelothrix - classification; Erysipelothrix - genetics; Erysipelothrix - immunology; Erysipelothrix - isolation & purification; Erysipelothrix rhusiopathiae; Fundamental and applied biological sciences. Psychology; Microbiology; Miscellaneous; Phylogeny; Plasmids; Polymerase Chain Reaction - veterinary; Polymorphism, Restriction Fragment Length; Restriction fragment length polymorphism; Swine; Swine Erysipelas - epidemiology; Swine Erysipelas - microbiology; Swine Erysipelas - prevention & control; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects)
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2006.02.015

Swine erysipelas vaccines are routinely used to protect pigs against peracute and acute/urticarial forms of Erysipelothrix. Between 1995 and 1998, 34 swine herds across four Australian states experienced vaccine failure. Forty-four isolates of Erysipelothrix rhusiopathiae of serovars 2, 1a, 1b and 1b × 21 were recovered from 15 of these 34 vaccine breakdown herds. These isolates were characterised by restriction fragment length polymorphism (RFLP) analyses using RsaI and AluI on whole cell DNA and for the presence of plasmid DNA. Results were compared with those of 20 isolates from 16 herds unaffected by vaccine breakdown and 13 isolates representing 10 reference strains. The majority of breakdown herds possessed isolates of serovar 2 (9/15 herds), followed by serovar 1a (5 herds). No geographic predominance of a single serovar was evident. The identification of 10 RsaI profiles from whole cell DNA among the 44 isolates from 15 breakdown herds indicated that a single, new clonal lineage of E. rhusiopathiae was not responsible for vaccine failure. RsaI RFLP analyses detected a further 14 distinct profiles among 20 field strains unassociated with vaccine breakdowns, and none matched profiles of the 10 serovar reference strains for serovars 1a, 1b, 2 or 21. This technique is recommended for epidemiological studies of E. rhusiopathiae strains.