Arbitrarily primed PCR analysis of Mycoplasma hyopneumoniae field isolates demonstrates genetic heterogeneity.

Mycoplasma hyopneumoniae is the primary agent of mycoplasmal pneumonia in swine. In this study we performed an arbitrarily primed PCR (AP-PCR) analysis, in which low-stringency amplification with a single primer was used, to investigate genetic variability in M. hyopneumoniae strains and field isolates. We performed preliminary experiments to examine the efficacy of 40 different 10-mer oligonucleotides for priming an AP-PCR with M. hyopneumoniae JT (T = type strain) chromosomal DNA. On the basis of our results, we selected primers OPA-3, OPA-17, and OPB-10 for use in an analysis performed with 23 field isolates. The most informative results were obtained with primer OPA-3. A total of 21 of 23 clinical isolates produced multiband patterns with this primer, while 2 isolates failed to produce any detectable bands. Our data show that M. hyopneumoniae is genetically diverse and that M. hyopneumoniae strains can be divided into at least six epidemiological subgroups on the basis of AP-PCR results.