First Report and Comparative Genomic Analysis of Mycoplasma capricolum subsp. capricolum HN-B in Hainan Island, China

Mycoplasma capricolum subsp. Capricolum (Mcc) is an important member of the Mycoplasma mycoides cluster (Mm cluster) and causes caprine contagious agalactia. Mcc can infect goats of all age groups, especially pregnant ewes and kids. It can cause the abortion in pregnant ewes and the death of goat kids, leading to enormous losses in the goat breeding industry. To date, the prevalence of epidemic Mcc strains on Hainan Island, China, remains unclear. This study aimed to isolate and identify Mcc strains endemic to Hainan Island, China. Genome sequencing and comparative genomic analysis were performed to reveal the molecular characteristics and evolutionary relationships of the isolated strain. Mcc HN-B was isolated and identified in Hainan Island, China. The Mcc HN-B genome consists of a 1,117,925 bp circular chromosome with a 23.79% G + C content. It contains 912 encoding genes, 3 gene islands, and 14 potential virulence genes. The core genome with the features of the Mm cluster and the specific genes of Mcc HN-B were identified by comparative genomic analysis. These results revealed the evolutionary relationship between Mcc HN-B and other members of the Mm cluster. Our findings provide a reference for further studies on the pathogenic mechanism and local vaccine development of Mcc.