Isolation and identification of mycoplasmas from the nasal cavity of sheep

Mycoplasmas isolated from the nasal cavity of sheep in a ram test station were examined to determine their identity and prevalence. Specimens were obtained for mycoplasmal culture in 1980, 1982, and 1983 from 558 sheep, and mycoplasmas were isolated from 630 specimens from 320 sheep (57.3%). The isolates were characterized and differentiated into groups on the basis of sensitivity to digitonin, fermentation of glucose, and hydrolysis of arginine. Isolates in some groups were further characterized by use of additional diagnostic media, and their identity was confirmed by agglutination or growth inhibition with antiserum prepared from reference mycoplasmas. Of the 320 sheep with mycoplasmas, 293 had Mycoplasma ovipneumoniae, 12 had M arginini, and 1 had M capricolum. Two sheep had Acholeplasma spp, and 3 sheep had unidentified Mycoplasma spp. The remaining 9 sheep had M ovipneumoniae in combination with Acholeplasma spp (n = 3), M arginini (n = 3), M capricolum (n = 2), and an unidentified Mycoplasma spp (n = 1). The biochemical reactions of the M ovipneumoniae from the 293 sheep were similar, but varied in the degree of growth and fermentation in the basal medium containing glucose. The high prevalence of M ovipneumoniae indicated that it may be commensal in the upper respiratory tract of healthy sheep.