Global Gene Expression Profiles of Cecropin B Induces Resistance in Haemophilus parasuis

To understand the mechanism of the adaptations, global gene expression profiles of the cecropin B--resistant strains of Haemophilus parasuis, The development of cecropin B (CB) resistance in H. parasuis SH0165 by exposing SH0165 using various concentrations of CB was investigated. One colony of bacterial cultures grown on TSA containing 30μg/mL CB was named CBR30, CBR30 cultured in TSA without CB for 50 passages was named CBR30-50. we used microarray technology to analyze the variation of the H. parasuis SH0165 transcriptional profile in CBR30 and CBR30-50. Our analysis to identify several genes whose system could be involved in inorganic ion transport, amino acid transport, and metabolism. Quantitative PCR was used to validate the differential expression of selected genes. The H. parasuis SH0165 control group was normal culture with no tilmicosin at OD600 >0.3 (12 h). The H. parasuis CBR30 was normal culture with 30μg/mL cecropin B at OD600 >0.3 (20 h). The H. parasuis CBR30-50 was normal culture with no cecropin B at OD600 >0.3 (12 h). Three independent experiments were performed on each group using a different sample for each experiment.