Genomic, protein homogeneity and antigenic variability of Mycoplasma agalactiae

Solsona, Michel; Lambert, Maurice; Poumarat, François

doi:10.1016/0378-1135(95)00200-6

Cited by 57 publications

(39 citation statements)

References 31 publications

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“…Importantly, genetic variability between M. bovis isolates was already demonstrated by McAuliffe et al using several other molecular DNA techniques (26). Those authors observed two distinct groups of M. bovis isolates, and an earlier report also showed the existence of two distinct groups of M. agalactiae isolates based on antigenic profiles (39). Whether the presence of the minor peaks coincides with these subgroups is not yet known.…”

Section: Discussionmentioning

confidence: 87%

Evaluation of tRNA Gene PCR for Identification of Mollicutes

et al. 2005

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We evaluated the applicability of tRNA gene PCR in combination with fluorescent capillary electrophoresis with an ABI310 genetic analyzer (Applied Biosystems, Calif.) for the identification of different mollicute species. A total of 103 strains and DNA extracts of 30 different species belonging to the genera Acholeplasma, Mycoplasma, and Ureaplasma were studied. Reproducible peak profiles were generated for all samples, except for one M. genitalium isolate, the three M. gallisepticum isolates, and 8 of the 24 Ureaplasma cultures, where no amplification could be obtained. Clustering revealed numerous discrepancies compared to the identifications that had been previously obtained by means of biochemical and serological tests. Final identification was obtained by 16S rRNA gene amplification followed by sequence analysis and/or restriction digestion. This confirmed the identification obtained by tRNA gene PCR in all cases. Seven samples yielded an unexpected tRNA gene PCR profile. Sequence analysis of the 16S rRNA genes showed that six of these samples were mixed and that one had a unique sequence that did not match any of the published sequences, pointing to the existence of a not-yet-described species. In conclusion, we found tRNA gene PCR to be a rapid and discriminatory method to correctly identify a large collection of different species of the class of Mollicutes and to recognize not-yet-described groups.Having no cell wall, Mollicutes form a special class of bacteria. Their small, compact genomes evolved from AT-rich, gram-positive bacteria by means of genome reduction. At the same time, they developed innovative mechanisms to survive as parasitic organisms in a wide variety of host environments. To date, eight genera belonging to the class Mollicutes have been described, and within these genera, up to 200 species, mostly of the genus Mycoplasma, are acknowledged. This variety of species is associated with several taxonomic ambiguities (15,17,18), and a correct identification may be very difficult for numerous reasons. First, a number of Mollicutes, especially the plant-pathogenic spiroplasmas, have not been cultivated, while others require very complex media. As a result, for some species, only a limited number of isolates exist, and these are often not easily accessible. Second, as more sequences and better isolation media become available, more species are continuously being discovered. Finally, for some species, limited data and very few reports are published, especially for less-virulent and nonvirulent species.To correctly differentiate all these species, a universal and fast identification technique would be extremely useful. Some promising methods have already been described (see, e.g., reference 25), but they do not yield digitized data, making exchange between laboratories difficult. An optimized tRNA gene PCR technique, originally described by Welsh and McClelland (27,48), has been shown to be useful for correct and reproducible identification of very diverse bacterial species when combined with hig...

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Section: Discussionmentioning

confidence: 87%

Evaluation of tRNA Gene PCR for Identification of Mollicutes

et al. 2005

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“…Frey et al [28] found that the chromosomal heterogeneity as demonstrated by PFGE of M. hyopneumoniae strains from different countries was markedly larger than between strains isolated from the same laboratory. Solsona et al [29] also found that the antigenic variability of 31 M. agalactiae strains was related to the geographic origin of the strains. In a study by Barile et al [30] strains isolated from the same sources were found to form clusters of strains having very high genomic homologies.…”

Section: Discussionmentioning

confidence: 95%

Antigenic and genomic homogeneity of successive Mycoplasma hominis isolates

Jensen¹,

Thorsen²,

Møller³

et al. 1998

Journal of Medical Microbiology

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Sixty Mycoplasma horninis isolates were obtained from the cervices of pregnant women and from the ears or pharynges of their newborn babies. The isolates were examined by SDS-PAGE and pulsed-field gel electrophoresis. Antigenic and genomic profiles were obtained for 16 series with two or more successive isolates. Both analyses led to the conclusion that isolates from the same woman were identical or nearly identical, while isolates from different women exhibited a high degree of variation with respect to both genomic and antigenic profiles.

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“…No correlation could be established between the individual ELISA titres and the severity of clinical signs. These variations in the antibody response detected by ELISA may be due to the well-established antigenic variability of mycoplasmas [6], including M. agalactiae [1,20]. The infection of the udder seemed to be a prerequisite for the development of a serological response but did not appear to be sufficient.…”

Section: Discussionmentioning

confidence: 99%

Inoculation of lactating ewes by the intramammary route with Mycoplasma agalactiae: comparative pathogenicity of six field strains

et al. 2000

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-Contagious agalactia affects goats and sheep. In most infected sheep, the causal agent, Mycoplasma agalactiae, induces mastitis and/or agalactia, keratoconjunctivitis and arthritis. However, a few strains of M. agalactiae were isolated from tank milk from flocks without any clinical signs. The present study was undertaken to compare these apparently "asymptomatic" strains to classical virulent strains in order to assess the pathogenicity of four "asymptomatic" strains. Six groups of lactating ewes were inoculated by the intramammary route with 10 8 viable mycoplasmas of each strain. The clinical signs were regularly evaluated; the excretion of bacteria in milk and the serological response were measured. Ewes were necropsied 7 weeks after inoculation and the level of infection in retromammary lymph nodes was determined. Among the 4 apparently "asymptomatic" strains, 2 were fully virulent as were the strains isolated from diseased animals, and the other 2 induced somewhat less severe clinical symptoms. The other parameters, in particular the level of excretion in milk and the level of infection of regional lymph nodes following necropsy were similar for all strains. Mean antibody response was also comparable between the apparently "asymptomatic" and virulent strains, in spite of great individual variability. This observation shows that flocks without any clinical sign from which M. agalactiae is isolated in bulk milk, must be kept under strict control since mycoplasmas may induce severe outbreaks later with changing conditions of breeding.contagious agalactia / Mycoplasma agalactiae / virulence / experimental infection / sheep disease Résumé -Inoculation de Mycoplasma agalactiae par voie intramammaire chez des brebis en lactation : virulence comparée de 6 souches de terrain. L'agalactie contagieuse affecte les chèvres et les moutons. Chez la plupart des moutons infectés, l'agent causal, Mycoplasma agalactiae, induit des mammites et/ou de l'agalactie, des kératoconjonctivites et des arthrites. Cependant, quelques Vet. Res. 31 (2000) 329-337 329

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Genomic, protein homogeneity and antigenic variability of Mycoplasma agalactiae

Cited by 57 publications

References 31 publications

Evaluation of tRNA Gene PCR for Identification of Mollicutes

Evaluation of tRNA Gene PCR for Identification of Mollicutes

Antigenic and genomic homogeneity of successive Mycoplasma hominis isolates

Inoculation of lactating ewes by the intramammary route with Mycoplasma agalactiae: comparative pathogenicity of six field strains

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