Genome wide transcriptional portrait of Actinobacillus pleuropneumoniae during invasive disease reveals new strategies for survival and persistence in the host

The transcriptional profile of the porcine lung pathogen, Actinobacillus pleuropneumoniae, was monitored during the acute phase of infection in its natural host. Bacterial expression profiles of A. pleuropneumoniae isolated from lung lesions of 25 infected pigs were compared in samples taken 6, 12, 24 and 48 hours post infection. A 84 chip study using total RNA recovered from A. pleuropneumoniae serotype 2 (4226) and serotype 6 (7712640) isolated from infected pig lung tissue during the first 48 of infection. Samples were taken 6, 12, 24 and 48 hours post infection, respectively. Before hybridization the samples were enriched for bacterial RNA and submitted to linear amplification. Each chip measures the expression level of 4,876 target genes from A. pleuropneumoniae with each gene covered by an average of 26.7 probes. Three biological replicates per sample. Microarray data from 3 pigs (no. 39, no. 43 and no. 72) were omitted from the final analysis due to poor signal intensity. A total of 75 microarrays were included in the final analysis.