Presence and genetic diversity of Mycoplasma suis group related to reproductive disorders in breeding pigs

Porcine Haemoplasma (PH) is a group of bacteria that parasitize the surface of erythrocytes and cause infectious anemia in pigs of all ages and reproductive disorders in sows, in which Mycoplasma suis (M. suis) plays a major role. This study aimed to survey the presence and genetic diversity of M. suis group in farms with clinical reproductive disorders in sows. A total of 150 samples, including blood samples from sows with reproductive disorders and their fetuses/weak-born piglets were collected from 10 pig farms in 6 provinces in Vietnam. The presence of M. suis group was determined by PCR and the 16S rRNA gene was amplified and sequenced to analyze the genetic diversity of the pathogen. The DNA of M. suis group was identified in 137/150 (91.33%) of sow samples with reproductive disorders. Fourteen strains of M. suis group were successfully sequenced based on the 16S rRNA gene. The sequences showed a high percentage of genetic similarity, with 93.72% to 100% identity to M. suis and 97.1 to 100% to M. parvum. Through phylogenetic analysis, the sequences were identified as belonging to M. suis group that there were at least 4 nucleotide types. In conclusion, M. suis group is present at a high rate in pig breeding farms in Vietnam. This is the first report about the genetic diversity of the 16S rRNA gene of M. suis group in Vietnam.