Mycoplasma hyopneumoniae diversity was determined using a molecular typing method based on the polyserine repeat motif within the p146 gene by Pablo Tamiozzo of the Universidad Nacional de Río Cuarto in Argentina and co-authors there and at Universidad Nacional del Centro de la Provincia de Buenos Aires.

In Journal of Swine Production and Health, they explain that three related farms in Argentina (A, B, and C) were investigated. To obtain a population free of enzootic pneumonia on Farm C, a partial depopulation programme had been carried out first on Farm A and then on Farm B. Finally, Farm C was populated with early-weaned piglets from Farm B.

To evaluate the success of the partial depopulation programme, the farms were monitored for clinical signs and by serological testing, lung examination at slaughter and nested polymerase chain reaction (nPCR).

They were ofund to be free of enzootic pneumonia but M. hyopneumoniae remained despite the eradication measures applied.

An outbreak of enzootic pneumonia in Farm C triggered an investigation of M. hyopneumoniae genetic diversity in these farms.

For this purpose, all DNA samples obtained from PCR-positive nasal swabs were further characterised using another nPCR designed for M. hyopneumoniae typing.

Several M. hyopneumoniae types were identified in these farms but one strain seemed to be present before and after the application of the partial depopulation programme. Unambiguous discrimination of M. hyopneumoniae would require analysis of other genomic regions.

Reference

Tamiozzo P., P.M.A. Lucchesi and A. Ambrogi. 2103. Monitoring for Mycoplasma hyopneumoniae before and after a partial depopulation program using a typing scheme based on the polyserine repeat motif of p146. J Swine Health Prod. 21(6):309–312.

January 2014