Differential transcriptomes of P. aeruginosa PAO1 upon continuous exposure to antibiotic-impregnated catheters
Purpose: The goals of this study are to compare RNA-Seq transcriptomic data of P. aeruginosa PAO1 in response to chronic exposure of clindamycin and rifampicin eluted from antibiotic-impregnated catheters in a continuous biofilm culture condition. Methods: Transcriptomic profiles of P. aeruginosa PAO1 grown with catheters without antibiotic coating or with clindamycin/rifampicin coating were generated by deep sequencing, in quadruplicates, using Illumina NextSeq 550 sequencer with SE-75. FastQC and Trimmomatic (v0.39) were used for sequencing quality assessment. Raw read counts of the annotated genes were calculated using HTSeq-count. The log2 fold change and false discovery rate (FDR) were measured by edgeR. Genes with |log2FC| > 1.0 and FDR < 0.05 were considered as differential expression genes. Transcripts per million (TPM) was measured by Kallisto, which is an alignment free expression estimation tool. Results: P. aeruginosa PAO1 RNA sequencing using Illumina NextSeq 550 sequencer generated 5,205,190 of average number of reads with average read length of 65 bp and a mean coverage of 54X. Differentially regulated proteins of 877 in the planktonic cells were identified, 55 of which displayed up-regulation and 822 displayed down-regulation. On the other hand, 178 proteins were differentially expressed in the biofilm cells containing 152 up-regulated and 26 down-regulated. Conclusions: Our study represents the first detailed analysis of transcriptomes generated by RNA-seq technology after P. aeruginosa PAO1 planktonic and biofilm cells were continuously exposed to clindamycin/rifampicin-impregnated catheters. Our results show that RNA sequencing offers a comprehensive and more accurate quantitative and qualitative evaluation of mRNA content of strain PAO1 cells. We conclude that RNA-seq based transcriptome characterization would help the understanding for the mechanism of antimicrobial resistance and virulence in P. aeruginosa after exposure of antimicrobial-coated catheter. Overall design: Comparison between planktonic and biofilm cells growng with catheters without antibiotic coating or with clindamycin/rifampicin coating