Genetic characteristics and antimicrobial susceptibility of porcine mycoplasma isolated in Thailand

Abstract

Porcine mycoplasmosis is the importance disease caused the respiratory problems, arthritis and synovitis in several ages of pigs. The diseases suppressed the animal performance and caused the economic loss in pig industry. The complicated diagnosis limits the study of Mycoplasma spp. in Thailand. The advantage of this study is to provide the necessary information and guideline of diagnosis, occurrence, epidemiology, management and treatment for the reduction of porcine mycoplasmosis from Thai pig industry. The available species and occurrence of mycoplasmas from nursery and slaughtered pigs were M. hyopneumoniae (15.6% from lung), M. hyosynoviae (7.9% from tonsil), and M. hyorhnis (61.1% from nasal swab, 18.2% from lung, and 63.5% from tonsil). The DNA fragment of the field strains were varied from 11 to 20 patterns while the genetic variation of the antimicrobial resistant strains was increased in the different farms and the sick pigs. M. hyorhinis showed the highest variation and conferred high MICs level and resistance to tylosin (48.8%), enrofloxacin (41.8%), and lincomycin (6.5%) comparing to other species. The resistance to enrofloxacin (34.6%) was detected in M. hyopneumoniae while M. hyosynoviae was resisted to doxycycline (46.2%) and tylosin (7.7%). There was no resistance to tiamulin and valnemulin. M. hyopneumoniae vaccination was more effective than medication for M. hyopneumoniae control while medication were effective for M. hyosynoviae and M. hyorhinis. The risk factors to the occurrence of porcine mycoplasmas were included the multiple sites, all-in-all-out in fattening, gilt acclimatization procedure, and other viral diseases. Because there were variation of genetic, antimicrobial susceptibility, and risk factors of the difference species, the accurate diagnosis was also important for porcine mycoplasmosis control.