Detection of Mycoplasma hyopneumoniae in nose swabs from pigs by in vitro amplification of the 16S rRNA gene.

We report the use of PCR to detect DNA from Mycoplasma hyopneumoniae, the etiological agent of enzootic porcine pneumonia. A primer set was designed for the amplification of a 649-bp fragment of the 16S rRNA gene from M hyopneumoniae. The PCR product was identified by ethidium bromide staining after gel electrophoresis and by Southern hybridization with an M. hyopneumoniae-specific oligonucleotide probe. No amplification was observed from any other porcine bacteria tested, including several closely related mycoplasmas. It was also possible to demonstrate the presence of M. hyopneumoniae in bronchial lavage samples and lung tissue samples from experimentally infected pigs. Furthermore, the PCR system was used for analysis of nasal samples obtained from pigs in a fattening herd. By this method, we were able to detect M. hyopneumoniae in nose swabs from naturally infected pigs. However, our results suggest that M. hyopneumoniae can be detected in the nasal cavities only during a limited time period.