Genotypic heterogeneity among strains ofMycoplasma gallinarum

Molecular epidemiology of Mycoplasma mycoides subsp. mycoides biotype Small Colony, the agent of contagious bovine pleuropneumonia

Restriction endonuclease analysis (REA) and immunoblotting were used to compare field strains of Mycoplasma mycoides subsp. mycoides biotype Small Colony from different parts of Europe and Africa. Of the 27 strains tested by REA, the European ones (n = 15), except 3 from the Iberian peninsula, differed strikingly from the African ones (n = 10). Vaccinal strains T1-SR and KH3J had a unique REA pattern. Polyclonal immunoblot profiles of 46 strains appeared fairly similar. However most of the Italian strains (22 out of 24) shared a characteristic, in the 100 kDa area, unlike that of the other European strains. Immunoprofiles of the reference strain PG1 and vaccinal strain T1-SR were different from the others. These results allowed the determination of possible links between different geographic region of enzootic contagious bovine pleuropneumonia.

Recombinant DNA probes and polymerase chain reaction for detection of Mycoplasma gallisepticum strains

Two recombinant DNA clones, pMG286.2 and pMG301.1, were isolated from the partial genomic library of Mycoplasma gallisepticum strain S6. Recombinant M. gallisepticum specific fragments were used as probes in Southern hybridisation with 10 M. gallisepticum strains whose DNA was digested by EcoRI, HindIII, BglII, RsaI and BamHI. The 1.5 kb fragment pMG301.1 did not show polymorphism in hybridisation patterns with M. gallisepticum strains, while the 3.5 kb fragment pMG286.2 enabled differentiation of M. gallisepticum strains into clusters. The DNA sequence of pMG301.1 was used to design a pair of 27-mer oligonucleotides flanking a 1.3 kb genomic region. These two primers directed specific in vitro amplification of all M. gallisepticum strains assayed giving an expected 1.3 kb product. Digestion of polymerase chain reaction products by DdeI enabled simple differentiation between clusters of M. gallisepticum strains and may be useful for improved epizootiological studies of M. gallisepticum infections in poultry.