Summary auto-generated
This taxonomic proposal reclassifies the F38 group of mycoplasmas, which causes contagious caprine pleuropneumonia in goats. The authors propose designating F38-type strains as Mycoplasma capricolum subsp. capripneumoniae based on DNA-DNA relatedness studies showing approximately 70% genomic similarity to M. capricolum, with intragroup relatedness of 85-90% within each taxon. This subspecies relationship is supported by serological cross-reactivity but distinguished by marked differences in growth characteristics and biochemical properties. Consequently, the original M. capricolum strains are reclassified as M. capricolum subsp. capricolum. The F38 subspecies is fastidious and slow-growing, lacks arginine metabolism, and has a natural habitat in goat lungs. This formal nomenclature resolves longstanding taxonomic ambiguity and provides distinct designations useful for diagnostic identification and regulatory purposes in veterinary microbiology.
Key findings
- F38-type mycoplasmas are proposed as M. capricolum subsp. capripneumoniae, the confirmed causative agent of classical contagious caprine pleuropneumonia
- DNA-DNA relatedness of approximately 70% between F38 and M. capricolum strains supports a subspecies rather than species-level relationship
- The two subspecies can be distinguished by cultural fastidiousness, growth rate, and arginine metabolism, with F38 strains unable to metabolize arginine
- Original M. capricolum strains are reclassified as M. capricolum subsp. capricolum, with type strain California kid maintained as the subspecies reference
- Clear subspecific nomenclature resolves diagnostic and regulatory ambiguities regarding these closely related but distinct caprine mycoplasmas
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Abstract
A subspecies relationship with the existing species Mycoplasma capricolum is appropriate for the F38 group of mycoplasmas, the causative agent of classical contagious caprine pleuropneumonia. We believe that this classification is justified on the basis of the close DNA-DNA relationship recently reported for isolates belonging to the two groups and the other known serological and biological similarities and differences of these organisms. Strain F38T (T = type strain) and taxonomically indistinguishable strains are therefore proposed as members of a new subspecies of M. capricolum, M. capricolum subsp. capripneumoniae. Strain F38 (= NCTC 10192) is the type strain of M. capricolum subsp. capripneumoniae subsp. nov. As a consequence of this subdivision of the species M. capricolum, strains previously classified as M. capricolum are now necessarily relegated to subspecies status, as M. capricolum subsp. capricolum subsp. nov. Strain California kid (= ATCC 27343 = NCTC 10154) is the type strain of M. capricolum, as well as of M. capricolum subsp. capricolum. A taxonomic description of M. capricolum subsp. capripneumoniae and a brief amended description of M. capricolum subsp. capricolum are presented.