“Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method performed under isothermal conditions and has a high specificity and efficiency. We developed a LAMP assay targeting the 16S rRNA gene for rapid detection of Haemophilus parasuis. The results obtained from testing 31 H. parasuis strains and 28 other bacterial species strains showed that LAMP was as specific as, and more sensitive than, nested PCR. Fifty-five lung samples were collected from 55 AZD8055 cell line healthy pigs. All the samples were negative for H. parasuis by bacterial isolation, nested PCR and LAMP, respectively. In addition, 122 lung samples
were collected from 122 pigs with apparent respiratory problems. Sixty-five were positive by bacterial isolation. All the samples that were positive by bacterial isolation were also positive by nested PCR and LAMP. The LAMP assay BI 6727 solubility dmso demonstrated higher sensitivity than nested PCR, picking up 16 additional cases. The LAMP assay also gave a same result compared with the nested PCR when the two assays were used, respectively, to detect H. parasuis from samples obtained from experimentally infected pigs. We concluded that LAMP is a highly sensitive and reliable method for detection
of H. parasuis infection. Haemophilus parasuis is the etiological agent of porcine polyserositis and arthritis (Glasser’s disease) characterized by fibrinous polyserositis, meningitis and polyarthritis, causing severe economic losses to the swine industry (Oliveira & Pijoan, 2004). To date, 15 serovars of H. parasuis have been identified (Angen et al., 2007). Infection by H. parasuis can be acute or chronic, depending on the immunological status of the herd (Oliveira et al., 2001). The AMP deaminase H. parasuis infection can be controlled by vaccination and antibiotic treatment. However, a key element for controlling the disease is to obtain a correct diagnosis of the causative agent (Aarestrup et al., 2004; Oliveira & Pijoan, 2004). Isolation and microbiological
culture of H. parasuis can be ineffective due to the fastidious growth of the bacteria, which can be aggravated by previous antibiotic treatment of affected animals (Oliveira et al., 2001; Angen et al., 2007; Turni et al., 2009). Many DNA-based and immunological methods for H. parasuis detection have been developed, such as immunohistochemistry (Segales et al., 1997), oligonucleotide-specific capture plate hybridization assay (Calsamiglia et al., 1999), the complement fixation test (Takahashi et al., 2001), indirect hemagglutination test (Miniats et al., 1991), enzyme immunoassays (ELISA) (Miniats et al., 1991; Solano-Aguilar et al., 1999), PCR assay (Oliveira et al., 2001; Angen et al., 2007) and real-time PCR (Turni et al., 2009). Among these diagnostic tools, PCR-based methods are the most rapid and are able to detect a small amount of bacteria chromosomes.