Project description:Using Nanopore sequencing, our study has revealed a close correlation between genomic methylation levels and antibiotic resistance rates in Acinetobacter Baumannii. Specifically, the combined genome-wide DNA methylome and transcriptome analysis revealed the first epigenetic-based antibiotic-resistance mechanism in A. baumannii. Our findings suggest that the precise location of methylation sites along the chromosome could provide new diagnostic markers and drug targets to improve the management of multidrug-resistant A. baumannii infections.
Project description:Objectives: Colistin remains a last-line treatment for multidrug-resistant Acinetobacter baumannii and combined use of colistin and carbapenems has shown synergistic effects against multidrug-resistant strains. In order to understand the bacterial responses to these antibiotics we analysed the transcriptome of A. baumannii following exposure to each.
Project description:Acinetobacter baumannii AB042, a triclosan-resistant mutant, was examined for modulated gene expression using whole genome sequencing, transcriptomics, and proteomics in order to understand the mechanism of triclosan-resistance as well as its impact on A. Baumannii.
Project description:Acinetobacter baumannii is a major cause of nosocomial infections which can survive in different hospital environments and its multidrug-resistant capacity is major concern now-a-days. ppGpp dependent stringent response mediates reprogramming of gene expression with diverse function in many bacteria. A baumannii A1S_0579 gene is responsible for ppGpp production. Transcriptome analysis of early stationary phase cultures represents several differentially expressed genes in ppGpp deficient strain (∆A1S_0579). We found that the expression of csu operon, which is important in pili biosynthesis for early biofilm formation, was significantly reduced in the ppGpp-deficient strain. Our findings showed that ppGpp signaling plays critical role in biofilm formation, surface motility, adherence and virulence of A baumannii. This study is the first demonstration of the association between ppGpp and pathogenicity of A. baumannii.
Project description:The increasing rate of antibiotic-resistant bacteria has become a serious health threat. Thus, it is important to discover, characterize, and optimize new molecules to overcome infections caused by these bacteria. It is known that Acinetobacter baumannii has a high capacity to avoid antibacterial drugs. Consequently, these bacteria have emerged as one of responsible for hospital and community-acquired infections. However, how this pathogen infects and survives inside the host cell is unknown. Here we analyze the time-resolved transcriptional profile changes on human epithelial HeLa cells after A. baumannii. Our results show how A.baumannii can survive in host cells and starts replication at 4 hours post infection. We sequenced RNA to obtain a set of differentially expressed gen (DEGs) used for a Gene Ontology (GO) and KEGG pathway analysis. The results show us how host bacteria is altering the host cells environment for their own benefit. We also determine chromosomal regions affected by our set of genes. Furthermore, we obtain protein-protein networks that reveal highly interacted proteins. The combination of these results will pave the way to discover new antimicrobial candidates for multidrug-resistant bacteria.
Project description:RNA sequencing transcriptomics was performed on a highly multidrug resistant A. baumannii strain belonging to international clone I, AB5075_UW and a transposon insertion inactivated mutant of ABUW_1016 (cbl), which encodes a LysR-type transcriptional regulator.Transcriptomics suggests that Cbl controls expression of the genes involved in acquisition and reduction of various sulfur sources in A. baumannii.
Project description:The bacterial pathogen, Acinetobacter baumannii, is a leading cause of drug-resistant infections. Here, we investigated the potential of developing nanobodies that specifically recognize A. baumannii over other Gram-negative bacteria. Through generation and panning of a synthetic nanobody library, we identified several potential lead candidates. We demonstrate how incorporation of next generation sequencing analysis can aid in selection of lead candidates for further characterization. Using monoclonal phage display, we validated the binding of several lead nanobodies to A. baumannii. Subsequent purification and biochemical characterization revealed one particularly robust nanobody that broadly and specifically bound A. baumannii compared to other common drug resistant pathogens. These findings support the potentially for nanobodies to selectively target A. baumannii and the identification of lead candidates for possible future diagnostic and therapeutic development.
Project description:Background: Acinetobacter baumannii is one of the most dangerous multidrug-resistant pathogens worldwide. Currently, 50-70% of clinical isolates of A. baumannii are extensively drug-resistant (XDR) and available antibiotic options against A. baumannii infections are limited. There are still needs to discover specific de facto bacterial antigenic proteins that could be effective vaccine candidates in human infection. With the growth of research in recent years, several candidate molecules have been identified for vaccine development. So far, there is no public health authorities approved vaccine against A. baumannii. Methods: The purpose of this study was to identify immunodominant vaccine candidate proteins that can be immunoprecipitated specifically with patients’ IgGs. Relaying on hypothesis that IgGs of infected person have capacity to capture immunodominant bacterial proteins. Herein, outer membrane and secreted proteins of sensitive and drug resistant A. baumannii were captured by using IgGs obtained from patient and healthy control sera and were identified by LC-MS/MS analysis. Results: By using subtractive proteomic approach, we determined 34 unique proteins which were captured only in drug-resistant A. baumannii strain via patient sera. After extensive evaluation of predicted epitope regions, solubility, membrane transverse characteristics, and structural properties, we selected several notable vaccine candidates. Conclusion: We identified vaccine candidate proteins that triggered de facto response of human immune system against the antibiotic-resistant A. baumannii. Precipitation of bacterial proteins via patient immunoglobulins was a novel approach to identify the proteins which have potential to trigger to response in patient immune system.
