PT - JOURNAL ARTICLE AU - Carsten Kröger AU - Keith D. MacKenzie AU - Ebtihal Y. Al-Shabib AU - Morgan W. B. Kirzinger AU - Danae M. Suchan AU - Tzu-Chiao Chao AU - Valentyna Akulova AU - Alesksandra A. Miranda-CasoLuengo AU - Vivian A. Monzon AU - Tyrrell Conway AU - Sathesh K. Sivasankaran AU - Jay C. D. Hinton AU - Karsten Hokamp AU - Andrew D. S. Cameron TI - The primary transcriptome, small RNAs, and regulation of antimicrobial resistance in <em>Acinetobacter baumannii</em> AID - 10.1101/236794 DP - 2017 Jan 01 TA - bioRxiv PG - 236794 4099 - http://biorxiv.org/content/early/2017/12/19/236794.short 4100 - http://biorxiv.org/content/early/2017/12/19/236794.full AB - We present the first high-resolution determination of transcriptome architecture in the priority pathogen Acinetobacter baumannii. Pooled RNA from 16 laboratory conditions was used for differential RNA-seq (dRNA-seq) to identify 3731 transcriptional start sites (TSS) and 110 small RNAs, including the first identification in A. baumannii of sRNAs encoded at the 3’ end of coding genes. Most sRNAs were conserved among sequenced A. baumannii genomes, but were only weakly conserved or absent in other Acinetobacter species. Single nucleotide mapping of TSS enabled prediction of −10 and −35 RNA polymerase binding sites and revealed an unprecedented base preference at position +2 that hints at an unrecognized transcriptional regulatory mechanism. To apply functional genomics to the problem of antimicrobial resistance, we dissected the transcriptional regulation of the drug efflux pump responsible for chloramphenicol resistance, craA. The two craA promoters were both down-regulated &gt;1000-fold when cells were shifted to nutrient limited medium. This conditional down-regulation of craA expression renders cells sensitive to chloramphenicol, a highly effective antibiotic for the treatment of multidrug resistant infections. An online interface that facilitates open data access and visualization is provided as “AcinetoCom” (http://bioinf.gen.tcd.ie/acinetocom/).