Experimental pathogenicity evaluation of <i>Mycoplasma canadense </i>from bovine mastitis <i>in vitro </i>and <i>in vivo </i>laboratory models

Abstract

<i>Mycoplasma canadense, </i>a clinical isolate from milk of a mastitic buffalo, was experimentally tested for its pathogenic potential in hamster tracheal ring and rabbit fallopian tube explant organ cultures (<i>in vitro</i>)<i> </i>and rat and rabbit mammary gland (<i>in vivo</i>)<i> </i>models. The activity percentage reduction in <i>M. canadense </i>infected hamster tracheal rings was 99.1% in

comparison to 16.4% in control rings. <i>Mycoplasma canadense, </i>also induced complete ciliostasis at 11-day post-infection in rabbit fallopian tube explants. Histopathological lesions in these infected organ cultures were loss of cilia, desquamation or denudation of epithelium , infiltration of inflammatory cells and proliferation of macrophages as well as oedema in lamina propria. At the end of the experiments, <i>M. canadense </i>organisms were reisolated in pure colonies from the infected but not the control organ cultures. In the rat and rabbit mammary glands, <i>M. canadense </i>organisms persisted upto 6-day and 7-day postinfection, respectively and caused histopathological changes suggestive of subacute to chronic mastitis during the experimental period. The results indicate that the tested <i>M. canadense </i>clinical isolate was virulent.