Polymerase chain reaction for detection of Mycoplasma gallisepticum

A species-specific 760-base pair (bp) BamHI to EcoRI DNA fragment (fMG-2) was isolated from a Mycoplasma gallisepticum (MG) genomic library constructed in plasmid pUC8. Based on the DNA sequence data of fMG-2, a pair of 25 base primers, designated amplification (Amp) left (L) and right (R) primers, was synthesized. When used in the polymerase chain reaction (PCR), the Amp L and R primers directed amplification of DNA of 16 MG strains yielding an expected 732-bp product, but did not amplify DNA of Escherichia coli, calf thymus, lambda phage, pUC8 plasmid, or 16 other species of avian mycoplasmas. As low as 10(-6) picogram of MG DNA, a fraction of the total chromosomal content of one cell, was detected following amplification by PCR. PCR amplification products were visualized by either ethidium bromide/ultraviolet exposure or hybridization with a 481-bp probe (fMG-3) prepared from the central region of fMG-2.