Isolation, identification, biological characteristics analysis and inactivated vaccine research of Mycoplasma canis from respiratory tract of dogs in Yunnan Province, China

Meiling KOU^1*Tao Xu^2*Yinan Wang^1*Jiarui Xie^1*Jiangyan Huang^1*Yun Xin^2*Chao Chen^2*Qing Fan^3*Aiguo Mao^2*Haisheng Miao^1*

• ¹Yunnan Animal Science and Veterinary Institute, Kunming, China
• ²Kunming Police Dog Base of the Ministry of Public Security, Kunming, Yunnan Province, Kunming, Yunnan Province, China
• ³Guangxi Veterinary Research Institute, Department of Biotechnology, Nanning,Guangxi 530001, P.R.China, Nanning,Guangxi, China

Introduction Research on Mycoplasma canis remains limited, possibly because dogs in most regions are usually not raised on a large scale or in intensive farming. Furthermore, existing antibacterial drugs are often proven to be effective in inhibiting or eradicating M. canis, resulting in insufficient attention being paid to its pathogenic potential. However, with the widespread use of antibacterial drugs, an increase in drug resistance has been found in human Mycoplasma pneumoniae, bovine mycoplasma and avian mycoplasma. M. canis also faces similar challenges. Given the irreplaceable role of dogs as companion animals and work partners, it is crucial to enhance research on Mycoplasma canine, especially in the areas of epidemiology, diagnostic techniques, drug resistance mechanisms and vaccine development. This study found that M. canis inoculated into liquid Pleuropneumonia-Like Organisms (PPLO) medium at 37 ℃ could reach the growth peak within 24 hours and maintain this level for approximately 24 hours. The survival rate is higher in environments with PH values of 6.5, 7.0 and 7.5 respectively, and it is suitable for storage in neutral or weakly acidic environments. 5 mM of BEI inactivated agent can completely inactivate M. canis within 15 hours, and the experimental dogs produced specific antibodies within one week after vaccination with the inactivated vaccine, with a positive rate of 100%. It provides a theoretical basis and experimental evidence for the subsequent in-depth exploration of the pathogenic mechanism of M. canis and the development of its vaccine.