Patel, Hiren Mahendra (2008) The biochemical and molecular characterisation of 'Mycoplasma ovipneumoniae' strains from sheep with respiratory disease. (PhD thesis), Kingston University, .

Abstract

'Mycoplasma ovipneumoniae' is one of the most common species of mycoplasma to be isolated from ovine species presenting with respiratory disease globally and is associated with atypical pneumonia in both sheep and goats. Despite this, little is known in regards to its growth requirements, biochemical characteristics, pathogenicity, survival and molecular variability. The ability of different 'M. ovipneumoniae' strains to grow in various media adaptations, where PPLO broth had been replaced by a vegetable protein source was investigated. It was found that growth yields in TSB-1 medium were comparable to or higher than those seen in Eaton's medium, with yields reaching 10[sup]8 -10[sup]9 cfu ml[sup]-1 within 24hrs, with some strains. The ability of strains to utilise different sugars, alcohols and organic acids was also determined. All strains were classified by their ability to utilise the various different substrates tested at different concentrations. The patterns and kinetics of utilisation were highly variable amongst the strains. The production of H[sub]2O[sub]2 by 30 strains of ‘M. ovipneumoniae’ during the oxidation of NADH and/or [alpha]-GP was investigated. All strains showed NADH oxidation, whilst only 2 strains showed oxidation of both NADH and [alpha]-GP. The rates of NADH and/or [alpha]-GP varied amongst the strains as did the subsequent amount of H[sub]2O[sub]2 produced. This molecular epidemiology of the isolates was assessed using random amplified polymorphic DNA (RAPD) and pulsed field gel electrophoresis (PFGE). The results showed a large degree of genetic heterogeneity both within and between flocks but there was no apparent correlation between method, geographical origin and/or time of isolation. The persistence of ‘M. ovipneumoniae’ field strains was also assessed. The strains survived for longer in broth, regardless of temperature, but were dependent on medium constituents, surviving well in the presence of mucin.

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