Comparison of real-time PCR and culture isolation in colostrum-deprived pigs immunized and challenged with Haemophilus parasuis

Abstract

Aims: A real‐time PCR (RT‐PCR) based on the detection of the infB gene of Haemophilus parasuis is compared with culture isolation (Frandoloso et al., (2011) Clin Vaccine Immunol18, 50–58.), evaluating different subunit or commercial vaccines. Methods and Results: Samples from different tissues of 24 experimentally infected and challenged colostrum‐deprived piglets were tested. The RT‐PCR gave globally a 23·3% more of positive results than culture, and all samples being positive by culture were positive by RT‐PCR also. H. parasuis could not be cultured from any of the samples of the piglets included in the three vaccinated groups resulting in a strong protection, but it could be detected by RT‐PCR in six samples in the group immunized with the commercial vaccine, in three in that vaccinated with native proteins with affinity to porcine transferrin (NPAPT) administered intramuscularly and in only two in that immunized with NPAPT intratracheally. Conclusions: The RT‐PCR was more sensitive than culture for H. parasuis detection in the organs compared. Significance and Impact of the Study: The RT‐PCR evidenced that NPAPT vaccines were those yielding the best protection results in terms of H. parasuis clearance.

Histopathologic lesions in conventional pigs experimentally infected with Haemophilus parasuis serovar 5

“…synovitis in challenged pigs. The bacteriological culture of the swabs was not as successful as the investigation by PCR, which is concurrent with other studies (7,21). Therefore all other investigations of the joint and brain were only done using the more sensitive method.…”

“…Fibrinous exudate can be observed on the pleura, pericardium, peritoneum, synovia and meninges (12,20). The detection of H. parasuis by PCR can be more sensitive than culturing the bacterium (7).…”

Rapid and simple detection of Glaesserella parasuis in synovial fluid by recombinase polymerase amplification and lateral flow strip

“…Molecular methods have great application potential because of their rapidity, sensitivity, and specificity. Several molecular detection methods, including PCR [10, 11] and real-time PCR [12], have been developed for GPS diagnosis. However, these technologies require complicated instruments and skilled professionals, restricting their use in pig farms and veterinary clinics [13].…”

Development of a recombinase polymerase amplification assay for rapid detection of Haemophilus parasuis in tissue samples

“…Isolation and microbiological culture of H. parasuis is the gold standard for diagnosis of Glässer's disease, but it could be ineffective due to the fastidious growth of the bacteria, easily being overgrown by other bacterial contaminants and the previous antibiotic treatment of affected animals (Angen, Oliveira, Ahrens, Svensmark, & Leser, 2007, Oliveira et al, 2001, Turni, Pyke, & Blackall, 2010. A series of molecular diagnostic methods have been described for sensitive and specific detection of H. parasuis, such as polymerase chain reaction (PCR), real-time PCR, loop-mediated isothermal amplification (LAMP) and cross-priming amplification (CPA) (Angen et al, 2007, Chen, Chu, Liu, Zhang, & Lu, 2010, Frandoloso, Martinez-Martinez, Rodriguez-Ferri, & Gutierrez-Martin, 2012, Gou et al, 2018, Oliveira et al, 2001, Turni et al, 2010, Yang et al, 2010.…”