However, reagents for serotyping field isolates are not readily available, and a large number of isolates cannot be identified by serotyping and are designated GSK2118436 concentration as nontypeable (NT) [7]. Other serotyping methods, such as the indirect hemagglutination test [7–9] have been employed to identify NT isolates. Nonetheless, there are still NT isolates that do not have serovar-specific reagents and cannot be characterized. The

virulence of each serovar was determined in specific pathogen free pigs [5]. Molecular typing techniques are increasingly used to identify field isolates including NT isolates. These methods include polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) [10, 11], enterobacterial repetitive intergenic concensus-polymerase chain reaction (ERIC-PCR) [12, 13], restriction endonuclease analysis [14, 15], multilocus enzyme electrophoresis (MEE) [16], and multilocus sequence typing (MSLT) analysis [17]. The molecular typing methods have shown that considerable genetic diversity

exists among strains of isolates of a particular serotype and that the genotyping techniques were more learn more discriminating compared to conventional serotyping, especially for use in epidemiological studies. Each of these molecular typing techniques offers advantages and disadvantages. For example, restriction endonuclease experiments [14, 15] found distinct patterns of isolates from animals JPH203 molecular weight with systemic GPX6 disease compared to respiratory isolates from healthy animals but restriction enzymes are expensive. The PCR-RFLP method uses restriction enzymes and sometimes does not generate multiple bands [11]. Multilocus sequence typing (MSLT) is a technique that studies housekeeping genes [17]. However, the latter procedure requires isolation of genomic DNA, performing PCR, and

sequencing of PCR products. Both ERIC-PCR [12, 13, 18–20] and MSLT analysis [17] could detect strain variation but not all strains were classified as virulent or avirulent. Although ERIC-PCR has recently been extensively used to study the epidemiology of H. parasuis isolates [19–21], the random amplified polymorphic DNA (RAPD) technique has not been utilized for this purpose. However, RAPD has been used to distinguish other gamma-proteobacteria, including Salmonella spp. [22], E. coli O157 [23], and Klebsiella pneumonia[24]. Both ERIC-PCR and random amplified polymorphic DNA (RAPD) are global techniques since known primers can be easily synthesized, reagents are affordable and readily obtained, and the techniques have high levels of reproducibility. In the PCR-based RAPD method, DNA does not have to be double-stranded, highly purified, or of high molecular weight [25]. Both ERIC-PCR and RAPD can utilize DNA from crude lysates [13, 26, 27] which shortens the time needed for completing the assays.