Re-evaluation of the classical Mycoplasma lipophilum cluster (Weisburg et al. 1989) and description of two new clusters in the hominis group based on 16S rDNA sequences.

Abstract

The Mycoplasma lipophilum cluster (Weisburg et al. 1989) in the hominis group of the mollicutes is re-evaluated in this work to update the phylogenetic framework for classification of species within the genus Mycoplasma. Therefore, sequences of the 16S rRNA gene were determined from previously described species, and 11 were found to be closely related to the M. lipophilum cluster. A selection of members of the other hitherto defined clusters of the hominis group was included for phylogenetic analysis, revealing that the classical M. lipophilum cluster could be re-organized into two clusters, namely the M. lipophilum cluster and the Mycoplasma bovis cluster. The former was found to contain two species, while the latter contained 20 species. The two clusters were closely related, sharing an ancestral branch with the Mycoplasma synoviae cluster. Furthermore, the M. bovis cluster could be divided into subclusters. Interestingly, two species, Mycoplasma equigenitalium and Mycoplasma elephantis, formed a distinct and early branch of the M. lipophilum, M. bovis and M. synoviae clusters. This entity was termed the M. equigenitalium cluster. The clusters and subclusters could be verified by using neighbour-joining and maximum-likelihood analyses on a variety of data sets, bootstrap calculations, secondary structure analysis and signature nucleotides. Therefore, the new 16S rDNA data presented in this work were used to reevaluate the M. lipophilum cluster, leading to the definition of two additional clusters. At present, the mollicutes belonging to the hominis group can be classified into ten evolutionary lineages.

16S rDNA PCR and denaturing gradient gel electrophoresis; a single generic test for detecting and differentiating Mycoplasma species

“…Two species, Mycoplasma columbinum and M. columbinasale, could not be distinguished, although previous studies have indicated that they are less than 97 % similar by 16S sequence analysis (Pettersson et al, 2001). Even when cultures were obtained from several different collections the two isolates gave identical profiles.…”

“…Similarly, the canine mycoplasma M. maculosum showed a high degree of similarity to the lion mycoplasma M. leopharyngis by 16S and 16S-23S IGS analysis and gave identical DGGE profiles. Previous studies have also highlighted the high degree of similarity in 16S sequence and identical biochemical characteristics of these species (Pettersson et al, 2001).…”

Abattoir‐based survey of contagious bovine pleuropneumonia in cattle in Turkey

“…These results show that various strains of Mycoplasma species do circulate in Turkish cattle herds. M bovis, M alkalescens and M canadiense all belong to the hominis group of mycoplasmas but belong to different clusters, the lipophilum ‐cluster for M bovis and the hominis‐cluster for M alkalescens and M canadense (Pettersson and others 2000, 2001). These three species are pathogenic for cattle and may induce mastitis or fertility disorders in adult cows, or arthritis in calves (Pfutzner and Sachse 1996, Booker and others 1999, Infante‐Martinez and others 1999, Bielanski and others 2000, Butler and others 2000, Hirose and others 2001).…”

A New Integrative Conjugative Element Occurs in Mycoplasma agalactiae as Chromosomal and Free Circular Forms

“…In mollicutes, such an element has not been thoroughly described except for the ICEF of the human-infecting Mycoplasma fermentans strain PG18, in which it occurs in two versions, ICEF-I (1 copy) and ICEF-II (3 copies), and produces a circular form after excision from its locus (6). This mycoplasma belongs to the hominis phylogenic group, along with Mycoplasma agalactiae and Mycoplasma bovis (15), which are ovine-caprine and bovine pathogens, respectively.…”