Project description:Studies of expression of mechanims of defense of the Acinetobacter sp.5-2Ac.02 from airborne hospital environment under stress conditions, such as SOS response (ROS response, heavy metals resistant mechanisms, peptides), as well as Quorum network (acetoin cluster and aromatics biodegradation cluster). Characterization functional of AcoN-like as negative regulator protein from acetoin cluster in Acinetobacter spp. Strains
Project description:Purpose: The goal of this study was to elucidate the collateral effects associated with OXA-23 overexpression on the Acinetobacter baumannii global transcriptome. Results: Besides the 99.73-fold increase in blaOXA-23 transcript upon IPTG induction, no other transcripts showed more than a 2-fold change compared to the wildtype control. This suggests that OXA-23 over expression to levels similarly observed in multi drug resistant A. baumannii clinical isolates does not effect the transcriptome.
Project description:Acinetobacter baumannii is often highly resistant to multiple antimicrobials, posing a risk of treatment failure, and colistin is a "last resort" for treatment of the bacterial infection. However, colistin resistance is easily developed when the bacteria are exposed to the drug, and a comprehensive analysis of colistin-mediated changes in colistin-susceptible and -resistant A. baumannii is needed. In this study, using an isogenic pair of colistin-susceptible and -resistant A. baumannii isolates, alterations in morphologic and transcriptomic characteristics associated with colistin resistance were revealed. Whole-genome sequencing showed that the resistant isolate harbored a PmrBL208F mutation conferring colistin resistance, and all other single-nucleotide alterations were located in intergenic regions. Using scanning electron microscopy, it was determined that the colistin-resistant mutant had a shorter cell length than the parental isolate, and filamented cells were found when both isolates were exposed to the inhibitory concentration of colistin. When the isolates were treated with inhibitory concentrations of colistin, more than 80% of the genes were upregulated, including genes associated with antioxidative stress response pathways. The results elucidate the morphological difference between the colistin-susceptible and -resistant isolates and different colistin-mediated responses in A. baumannii isolates depending on their susceptibility to this drug.
Project description:In recent years, the Gram-negative bacterium Acinetobacter baumannii has garnered considerable attention for its unprecedented capacity to rapidly develop resistance to antibacterial therapeutics. This is coupled with the seemingly epidemic emergence of new hyper-virulent strains. Although strain-specific differences for A. baumannii isolates have been well described, these studies have primarily focused on proteinaceous factors. At present, only limited publications have investigated the presence and role of small regulatory RNA (sRNA) transcripts. Herein, we perform such an analysis, describing the RNA-seq-based identification of 78 A. baumannii sRNAs in the AB5075 background. Together with six previously identified elements, we include each of these in a new genome annotation file, which will serve as a tool to investigate regulatory events in this organism. Our work reveals that the sRNAs display high expression, accounting for >50 % of the 20 most strongly expressed genes. Through conservation analysis we identified six classes of similar sRNAs, with one found to be particularly abundant and homologous to regulatory, C4 antisense RNAs found in bacteriophages. These elements appear to be processed from larger transcripts in an analogous manner to the phage C4 molecule and are putatively controlled by two further sRNAs that are strongly antisense to them. Collectively, this study offers a detailed view of the sRNA content of A. baumannii, exposing sequence and structural conservation amongst these elements, and provides novel insight into the potential evolution, and role, of these understudied regulatory molecules. This study is based on the annotation of novel sRNAs on basis of an Acinetobacter baumannii RNA sequencing dataset. Each sample was generated by pooling three independent biological replicate RNA preps