Effects of LpxC and lpxD disruption on Acinetobacter baumannii and phage interactions
Ontology highlight
ABSTRACT:
ORGANISM(S): Acinetobacter baumannii Acinetobacter baumannii ATCC 19606 = CIP 70.34 = JCM 6841
PROVIDER: GSE302131 | GEO | 2025/07/31
REPOSITORIES: GEO
Similar Datasets
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.
2023-06-21 | GSE202972 | GEO
Project description:lpsB encodes a glycosyltransferase involved in lipopolysaccharide (LPS) synthesis. LPS is a major component of the Gram-negative bacterial outer membranes. We used custom-made Affymetrix A. baumannii strain ATCC 17978 derived GeneChips to compare the gene expression properties of wild type and isogenic lpsB mutant cells. Two mutants were evaluated; A. baumannii strain 5A7 is a ATCC 17978 derivative harboring a transposon (Tn5) within lpsB (A1S_0430 locus); A. baumannii strain containing a deletion of lpsB (A1S_0430). A. baumannii strain ATCC 17978, 5A7 (lpsB:Tn5) or IH1∆lpsB (∆lpsB) were grown to mid-exponential phase growth, total bacterial RNA was isolated and subjected to GeneChip hybridization and analysis. We sought to determine the transcription profile of lpsB mutated cells.
2012-12-01 | E-GEOD-40771 | biostudies-arrayexpress
Project description:lpsB encodes a glycosyltransferase involved in lipopolysaccharide (LPS) synthesis. LPS is a major component of the Gram-negative bacterial outer membranes. We used custom-made Affymetrix A. baumannii strain ATCC 17978 derived GeneChips to compare the gene expression properties of wild type and isogenic lpsB mutant cells. Two mutants were evaluated; A. baumannii strain 5A7 is a ATCC 17978 derivative harboring a transposon (Tn5) within lpsB (A1S_0430 locus); A. baumannii strain containing a deletion of lpsB (A1S_0430).
2012-12-01 | GSE40771 | GEO
Project description:The emergence of carbapenem-resistant Acinetobacter baumannii has been increasingly reported, leading to more challenges in treating its infections. With the development of phage therapy and phage-antibiotic combinations, it is possible to improve the treatment of bacterial infections. In the present study, a vB_AbaP_WU2001 (vWU2001 for short) phage-specific CRAB was isolated and the genome size is 40,792 bp in length. The novel phage vWU2001 belongs to the Autographiviridae family and the order Caudovirales. Shotgun proteomics identified 289 proteins. The broad host range phage vWU2001 displayed a high adsorption rate, short latent period, large burst size and good stability. The phage could reduce preformed biofilms and inhibit biofilm formation. The combination of phage vWU2001 and colistin had significantly higher bacterial growth inhibition activity than that of phage, or colistin alone. The efficacy of the combined treatment was also evaluated in Galleria mellonella. The evaluation of its therapeutic potential revealed that the combination of phage and colistin showed a significantly greater increase in G. mellonella survival and clearance of bacterial number compared to that of phage or colistin alone, indicating that the combination was synergistic against CRAB. The results demonstrated that phage vWU2001 has the potential to be developed as an antibacterial agent.
2021-09-04 | PXD028206 | JPOST Repository
Project description:Desiccation tolerance has been implicated as an important characteristic that potentiates the spread of the bacterial pathogen Acinetobacter baumannii through hospitals on dry surfaces. Despite the potential importance of this stress response, scarce information is available describing the underlying mechanisms of A. baumannii desiccation tolerance. Here we characterize the factors influencing desiccation survival of A. baumannii. At the macroscale level, we find that desiccation tolerance is influenced by cell density, growth phase, and desiccation medium. Our transcriptome analysis indicates that desiccation represents a unique state for A. baumannii compared to commonly studied growth conditions and strongly influences pathways responsible for proteostasis. Remarkably, we find that an increase in total cellular protein aggregates, which is often considered deleterious, correlates positively with the ability of A. baumannii to survive desiccation. We show that artificially inducing protein aggregate formation increases desiccation survival, and more importantly, that proteins incorporated into cellular aggregates can retain activity. Our results suggest that protein aggregates may promote desiccation tolerance in A. baumannii through preserving and protecting proteins from damage during desiccation until rehydration occurs.
2018-10-27 | GSE111383 | GEO
Project description:The long-term resistance to desiccation on abiotic surfaces is a key determinant of the adaptive success of Acinetobacter baumannii as a healthcare-associated bacterial pathogen. Here, the cellular and molecular mechanisms enabling A. baumannii to resist desiccation and persist on abiotic surfaces were investigated. Experiments were set up to mimic the A. baumannii response to air-drying that would occur when bacterial cells contaminate fomites in hospitals. Resistance to desiccation and transition to the “viable but nonculturable” (VBNC) state were determined in the laboratory-adapted strain ATCC 19606T and the epidemic strain ACICU. Culturability, membrane integrity, metabolic activity, virulence, and gene expression profile were compared between the two strains at different stages of desiccation. Upon desiccation, ATCC 19606T and ACICU cells lose culturability and membrane integrity, lower their metabolism, and enter the VBNC state. However, desiccated A. baumannii cells fully recover culturability and virulence in an insect infection model following rehydration in physiological buffers or human biological fluids. Transcriptome and chemical analyses of A. baumannii cells during desiccation unveiled the production of protective metabolites (L-cysteine and L-glutamate) and decreased energetic metabolism consequent to activation of the glyoxylate shunt (GS) pathway, as confirmed by reduced resuscitation efficiency of aceA mutants, lacking the key enzyme of the GS pathway. VBNC cell formation and extensive metabolic reprogramming provide a biological basis for the response of A. baumannii to desiccation, with implications on environmental control measures aimed at preventing the transmission of A. baumannii infection in hospitals.
2024-09-23 | GSE249021 | GEO
Project description:Virulent bacteriophages (or phages) are viruses that specifically infect and lyse a bacterial host. When multiple phages co-infect a bacterial host, the extent of lysis, dynamics of bacteria-phage and phage-phage interactions are expected to vary. The objective of this study is to identify the factors influencing the interaction of two virulent phages with different Pseudomonas aeruginosa growth states (planktonic, an infected epithelial cell line, and biofilm) by measuring the bacterial time-kill and individual phage replication kinetics. A single administration of phages effectively reduced P. aeruginosa viability in planktonic conditions and infected human lung cell cultures, but phage-resistant variants subsequently emerged. In static biofilms, the phage combination displayed initial inhibition of biofilm dispersal, but sustained control was achieved only by combining phages and meropenem antibiotic. In contrast, adherent biofilms showed tolerance to phage and/or meropenem, suggesting a spatiotemporal variation in the phage-bacterial interaction. The kinetics of adsorption of each phage to P. aeruginosa during single- or co-administration were comparable. However, the phage with the shorter lysis time depleted bacterial resources early and selected a specific nucleotide polymorphism that conferred a competitive disadvantage and cross-resistance to the second phage. The extent and strength of this phage-phage competition and genetic loci conferring phage resistance, are, however, P. aeruginosa genotype dependent. Nevertheless, adding phages sequentially resulted in their unimpeded replication with no significant increase in bacterial host lysis. These results highlight the interrelatedness of phage-phage competition, phage resistance and specific bacterial growth state (planktonic/biofilm) in shaping the interplay among P. aeruginosa and virulent phages.
2024-07-17 | GSE271537 | GEO
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
2016-03-30 | E-GEOD-75708 | biostudies-arrayexpress
Project description:Acinetobacter baumannii is a nosocomial Gram-negative pathogen that often displays multidrug-resistance due to its robust outer membrane and its ability to acquire and retain extracellular DNA. Moreover, it can survive for prolonged durations on surfaces and is resistant to desiccation. Discovering new antibiotics against A. baumannii has proven challenging through conventional screening approaches. Fortunately, machine learning methods allow for the rapid exploration of chemical space, increasing the probability of discovering new chemical matter with antibacterial activity against this burdensome pathogen. Here, we screened ~7,500 molecules for those that inhibited the growth of A. baumannii in vitro. We trained a deep neural network with this growth inhibition dataset and performed predictions on the Drug Repurposing Hub for structurally novel molecules with activity against A. baumannii. Through this approach, we discovered abaucin, an antibacterial compound with narrow-spectrum activity against A. baumannii, which could overcome intrinsic and acquired resistance mechanisms in clinical isolates. Further investigations revealed that abaucin perturbs lipoprotein trafficking through a mechanism involving LolE, a functionally conserved protein that contributes to shuttling lipoproteins from the inner membrane to the outer membrane. Moreover, abaucin was able to control an A. baumannii infection in a murine wound model. Together, this work highlights the utility of machine learning in discovering new antibiotics and describes a promising lead with narrow-spectrum activity against a challenging Gram-negative pathogen.
2023-02-01 | GSE214305 | GEO
Project description:Calprotectin (CP) inhibits bacterial viability through extracellular chelation of transition metals. However, how CP influences general metabolism remains largely unexplored. We show here that CP restricts bioavailable Zn and Fe to the pathogen Acinetobacter baumannii, inducing an extensive multi-metal perturbation of cellular physiology. Detailed here are the RNA sequencing files of WT A. baumannii ATCC 17978 grown plus or minus recombinant human calprotectin.
2019-03-26 | GSE125491 | GEO