Serologic cross-reactivity of Australian Moraxella bovis to vaccinal bacterin strains as determined by competitive ELISA

• Published in: Australian veterinary journal 2008-04, Vol.86 (4), p.124-129
• Main Authors: McConnel, C.S, Shum, L, Gleeson, B.L, House, J.K
• Format: Article
• Language: English
• Subjects: Animals; antigenic variation; Antigens, Bacterial - blood; Australia - epidemiology; bacterial infections; Bacterial Vaccines - immunology; Cattle; cattle diseases; Cattle Diseases - epidemiology; Cattle Diseases - immunology; Cattle Diseases - prevention & control; Cornea - microbiology; cross reaction; Cross Reactions; Disease Outbreaks - prevention & control; Disease Outbreaks - veterinary; enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - veterinary; epidemiological studies; Female; keratoconjunctivitis; Keratoconjunctivitis, Infectious - epidemiology; Keratoconjunctivitis, Infectious - immunology; Keratoconjunctivitis, Infectious - prevention & control; Male; Moraxella (Moraxella) bovis - classification; Moraxella (Moraxella) bovis - immunology; Moraxella (Moraxella) bovis - isolation & purification; Moraxella bovis; Moraxellaceae Infections - epidemiology; Moraxellaceae Infections - immunology; Moraxellaceae Infections - prevention & control; Prevalence; serotypes; strains; Vaccination - veterinary; vaccine strains; vaccines
• ISSN: 0005-0423; 1751-0813
• DOI: 10.1111/j.1751-0813.2008.00271.x

Objective  To conduct a serologic survey and define pili antigenic variability via the serologic cross‐reactivity of Moraxella bovis isolates from naturally occurring infectious bovine keratoconjunctivitis (IBK) outbreaks in Australia. This project applies to the development of an M bovis pili‐based vaccine targeting Australian strains originating from intensive cattle producing regions. Procedure  Ocular swabs were collected from cattle affected with clinical signs of IBK from 25 veterinary practices. Standard criteria were used to identify 70 M bovis. Pure, piliated isolates were evaluated with a modified competitive enzyme‐linked immunosorbent assay (ELISA) for cell‐bound M bovis pili to determine their serologic cross‐reactivity with pili of vaccinal bacterin strains EPP63, FLA64, and SAH 38. Results  Sixty‐four percent (45/70) of M bovis isolates demonstrated homologous pili antigens to a vaccinal strain. M bovis isolates homologous to one of the three vaccinal strains were obtained in 77% (34/44) of IBK outbreaks sampled. No IBK outbreak had isolates homologous to more than one vaccinal strain; however, 29% (10/34) of outbreaks with a cross‐reacting strain had non‐cross‐reacting strains as well. Conclusion  The similar prevalence of pilus antigen homology to strain FLA64 was observed with isolates derived from NSW, Tasmania, and Victoria, compared with results of prior smaller serologic studies, suggests that the common pilus antigens in M bovis within Australia have been relatively stable over the last 20 years. The prevalence of a limited number of pilus antigens in M bovis suggest that the application of a vaccine containing the bacterial strains EPP63, FLA64, and SAH38 may provide a useful management tool for reducing production losses associated with IBK in Australia.