Direct and Indirect Immunofluorescence of Unfixed and Fixed Mycoplasma Colonies

This report provides a description of indirect immunofluorescence of unfixed mycoplasma colonies (“indirect epifluorescence”). Comparison was made between direct and indirect immunofluorescence using unfixed and hot water fixed colonies. 7 mycoplasma strains were used, 6 of canine and 1 of human ( M. pneumoniae ) origin. It is concluded that indirect immunofluorescence of unfixed colonies is a useful serological method of identification. It is more sensitive than and equally specific as direct immunofluorescence and in addition does not give the background fluorescence associated with that method. It is also concluded that direct and indirect immunofluorescence of hot water fixed colonies is too unspecific for the identification of canine mycoplasma species. M. pneumoniae appears to differ in this respect as its antigenic specificity is apparently better retained during hot water fixation.