Lungs from pigs challenged with M. hyosynoviae were not
evaluated at necropsy. Immunohistochemistry was not
performed on lungs from pigs challenged with either M.
hyorhinis or M. flocculare because of the absence of
macroscopic lesions and PCR negative results in BAL fluids
(data not shown). The histological results of the animals
infected with M. hyopneumoniae identified microscopic
lesions suggestive of M. hyopneumoniae infection in all pigs
challenged with M. hyopneumoniae, which in combination
with positive PCR results in BAL from all pigs confirmed
active infection in that challenge group (Table S1). Samples
collected prior to challenge were negative for all four
mycoplasmas, and throughout the duration of the study, no
evidence of cross-contamination was identified. In addition,
no other swine pathogens were identified by culture.