Identification of genes transcribed by Haemophilus parasuis in necrotic porcine lung through the selective capture of transcribed sequences (SCOTS)

Abstract

Haemophilus parasuis is the aetiological agent of Glässer's disease, which has received more attention in the past decade due to the increasing economic losses in the pig industry worldwide. Little is known about the mechanisms by which H. parasuis survives in the host. In this study, selective capture of transcribed sequences (SCOTS) was used to identify H. parasuis genes upregulated in necrotic porcine lung 7 days post infection. Thirty-eight genes were identified that were upregulated during infection of the lung tissue of pigs, compared with growth in culture medium. In two examples chosen gene expression was not confined to the lungs, there being variation between tissues. The data support biofilm formation being an important mode of growth for colonization and/or persistence. Results from the in vitro studies suggest that, as for other pathogens, iron and oxygen restriction and heat stress are important environmental signals to regulate gene expression. This study has identified genes of H. parasuis that are upregulated during infection of porcine lung tissue as compared with in vitro growth conditions.

Distribution of genes involved in sialic acid utilization in strains of Haemophilus parasuis

“…Based on gene sequence homology, a number of genes encoding putative sialic acid-related enzymes have been annotated in the genome of H. parasuis strain SH0165 (Xu et al, 2011). In addition, Jin et al (2008) reported the transcription of a siaB/neuA homologue during infection, suggesting a role for sialic acid in the pathogenesis of this bacterium. In this study, we analysed the presence of the genes nanH, siaB, neuA and lsgB in strains from different clinical origins and studied their association with virulence mechanisms already described for H. parasuis.…”

Epidemiologia molecular de Haemophilus parasuis

“…O sorotipo 4 (39%) e os isolados não sorotipáveis (27%) foram os mais prevalentes nos rebanhos norte-americanos (OLIVEIRA et al, 2003) (KIELSTEIN & RAPP-GABRIELSON, 1992;NIELSEN, 1993). Outros estudos têm sido realizados para se comprovar a associação entre a expressão de fatores de patogenicidade e virulência em infecções por H. parasuis (JIN et al, 2008;DEL RÍO et al, 2006a;METCALF & MacINNES, 2007), embora nenhuma associação evidente com virulência pôde ser determinada. O desenvolvimento de ferramentas diagnósticas mais específicas, tais como a detecção de genes específicos para virulência, permitirá a identificação precisa de amostras virulentas.…”

Transcriptional responses of Haemophilus parasuis to iron-restriction stress in vitro

“…As in other Gram-negative microorganisms, lipopolysaccharide, capsule, certain outer membrane proteins, fimbriae and neuraminidase have also been linked to the virulence of this bacterium (del Río et al 2005). Approximately 40 differentially expressed genes of this pathogen have been identified from infected pig lungs in our previous study (Jin et al 2008). However, the overall contribution of each component to the infection process remains unclear.…”