Detection of a bacteriophage gene encoding a Mu-like portal protein in Haemophilus parasuis reference strains and field isolates by nested polymerase chain reaction.

A nested polymerase chain reaction (nPCR) assay was developed to determine the presence of a gene encoding a bacteriophage Mu-like portal protein, gp29, in 15 reference strains and 31 field isolates of Haemophilus parasuis. Specific primers, based on the gene's sequence, were utilized. A majority of the virulent reference strains and field isolates tested harbored the gene. The results suggest that the nPCR technique described in the current report could serve as a tool for epidemiological studies of H. parasuis.