Biochemical and molecular analysis were conducted on 34 strains of Mycoplasma species
isolated between 2003 and 2009 from the genital tract of clinically healthy Dorper sheep and
sheep with ulcerative vulvitis and balanitis. Earlier publications identified the causative
agent as Mycoplasma mycoides mycoides large colony (MmmLC) and Arcanobacterium pyogenes.
The aims of the study were to characterise Mycoplasma species isolated from the genital
tract of Dorper sheep with polymerase chain reaction assay, cloning and gene sequencing.
Basic Local Alignment Search Tool (BLAST) results revealed six predominant Mycoplasma
species: Mycoplasma arginini, Mycoplasma bovigenitalium, Arcanobacterium laidlawii, MmmLC,
Mycoplasma sp. ovine/caprine serogroup II and M. canadense. Sequencing of the 34 isolates
were analysed using phylogenetic methods, and 18 (50%) were identified as M. arginini with
99% – 100% similarity to M. arginini from England and Sweden. Six isolates showed 99%
similarity to M. bovigenitalium strains from Turkey and Germany. Two isolates had 99%
similarity to an M. sp. ovine/caprine sero group II from the United Kingdom. BLAST for
two isolates revealed 99% similarity to Acholeplasma laidlawii from India, another two were
99% similar to MmmLC strain from Sweden, two showed 98% similarity to Mycoplasma sp.
Usp 120 from Brazil, and two isolates have a 97% – 99% similarity to M. mm. Jcv1 strain from
the United States of America. Finally, one isolate showed similarity of 99% to Mycoplasma
canadense strain from Italy. The findings support the hypothesis that ulcerative vulvitis and
balanitis of Dorper sheep in South Africa (SA) is a multifactorial disease with involvement of
different Mycoplasma species.