Development of a sensitive nested PCR method for the specific detection of Mycoplasma mycoides subsp. mycoides SC.

A specific and sensitive test for the detection of Mycoplasma mycoides subsp. mycoides small colony type (SC), the aetiological agent of contagious bovine pleuropneumonia (CBPP) was developed using two nested PCR reactions. The PCR reactions are based on the nucleotide sequence of lipoprotein P72 of M. mycoides subsp. mycoides SC. The two specific oligonucleotide primer pairs were chosen to match those sequence segments of the P72 gene which differ most from the gene of the closely related lipoprotein P67 of Mycoplasma sp. bovine group 7 (strain PG50). The nested PCR reacted with all of the 34 different strains of M. mycoides subsp. mycoides SC analysed, and gave no amplification product with any of the closely related mycoplasmas tested, showing its high specificity. In bronchial lavage fluid experimentally contaminated with M. mycoides subsp. mycoides SC, the assay was able to detect as few as two viable cells per ml using a simple lysis procedure prior to the amplification step. With clinical samples, the sensitivity of the nested PCR was about 10(4)-10(5) higher than that of single PCR amplifications performed under the same conditions. The assay was also successfully used to detect M. mycoides subsp. mycoides SC in bronchial lavage fluid of experimentally infected cattle and proved to be more sensitive than classical culture methods.