E-Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2021

The role of regulatory RNAs in Acinetobacter baumannii (#207)

Michael A Burch 1 , Anton Y Peleg 1 2 , Deanna Deveson Lucas 1 3 , Marina Harper 1 , John D Boyce 1
  1. Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
  2. Department of Infectious Diseases, Alfred Hospital, Prahran, Victoria, Australia
  3. Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia

The Gram-negative bacterium Acinetobacter baumannii causes life-threatening nosocomial infections and has a near unparalleled capacity to develop multidrug-resistance. Small non-coding RNAs (sRNAs) regulate bacterial physiology, antibiotic resistance, and virulence in many pathogens; however, there has been limited characterisation of these important regulatory molecules in A. baumannii. We performed bioinformatic analysis on multiple whole-transcriptome RNA-sequencing datasets and identified more than 40 putative sRNAs that were highly conserved in strains AB5075, AB307-0294, ATCC 17978, and ATCC 19606; several of these putative sRNAs were selected for initial functional characterisation in AB307-0294. Northern blot analyses confirmed the expression and determined the approximate size of these sRNAs, fluorescent primer extension defined the 5’ end of each sRNA transcript, and quantitative reverse-transcription PCR was used to assess the expression level of each sRNA at different bacterial growth phases. Deletion mutants and overexpression strains were constructed for each of the sRNA genes. These strains were transcriptionally analysed to identify gene expression changes, relative to expression in wild-type AB307-0294. Small sets of genes were found to be dysregulated in each of the sRNA mutant strains and sRNA overexpression strains and phenotypic analyses of these strains are ongoing. In conclusion, A. baumannii encodes numerous, highly conserved putative sRNAs and available data suggests that at least some of these are true sRNA molecules that regulate small subsets of genes in AB307-0294.