A case of pericarditis caused by Mycoplasma hyorhinis in a weaned piglet

BACKGROUND: Mycoplasma hyorhinis (M. hyorhinis) is a bacterium commonly found in the upper respiratory tract of healthy pigs and an agent of polyserositis and polyarthritis. Moreover, it can carry antibiotic resistance genes (Wu et al, Vet. Microbiol. 76: 25–30, 2000). Economic losses caused by M. hyorhinis can be reduced by antibiotic therapy, however, isolation and antimicrobic susceptibility profile are rarely performed. CASE PRESENTATION: The present report describes a case of pericarditis caused by M. hyorhinis in a weaned piglet with respiratory symptoms and reduced growth performance. At post mortem examination, the main macroscopic finding was a severe fibrinous pericarditis and M. hyorhins was the only agent isolated from the pericardial fluid. In this strain, Minimum Inhibitory Concentration (MIC) determination revealed resistance to various antimicrobial molecules such as erythromycin, tylosin and tilmicosin. CONCLUSION: This paper highlights the importance of including M. hyorhins in the differential diagnosis of polyserositis in swine. Moreover, due the possible presence of multidrug resistance, the determination of antimicrobial susceptibility pattern should be performed on a regular basis.