Isolation of Mycoplasma hyorhinis and Mycoplasma arginini from the ears of pigs with otitis media.

Mycoplasmas were isolated from the middle ears and nasal cavities of clinically ill, young pigs that were slaughtered due to an unfavourable prognosis. The isolation rates of Mycoplasma hyorhinis were 27 of 43 (62.8 per cent) from the auditory tube, 22 of 43 (51.2 per cent) from the tympanic cavity, and 15 of 25 (60.0 per cent) from the nasal cavity. M arginini was also recovered at rates of 11 of 43 (25.6 per cent) from the auditory tube, 7 of 43 (16.3 per cent) from the tympanic cavity, and 9 of 25 (36.0 per cent) from the nasal cavity. Dual infections with M hyorhinis and M arginini occurred in these sites in some cases. M hyorhinis was isolated from 16 (80.0 per cent) of 20 pigs with otitis media diagnosed histologically, and from two (25.0 per cent) of eight pigs without this condition. The isolation rate was significantly different (P < 0.05) between the groups, suggesting either that the organism triggers development of the disease of the ear or that the agent(s) or factors responsible for otitis media in the pigs created favourable conditions at this site for colonisation by M hyorhinis.