Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: (A) GO enrichment analysis of A. baumannii A118 genes downregulated in response to WBBP compared to WBHV, within the Biological Process category. The X-axis represents the Signal value, and the Y-axis shows the GO term descriptions. GO terms were filtered using the following criteria: Term similarity ≥0.70, FDR ≤ 0.05, Signal ≥0.50, Strength ≥0.25, and Minimum count in the network was set to 10. (B) Heatmap showing 11 out of 18 acinetobactin operon genes downregulated in A. baumannii A118 in response to WBBP compared to WBHV (padj ≤ 0.05 and |log2foldchange| ≥ 1).

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques:

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: Standard growth curve of A. baumannii A118 grown in LB or LB + 10% serum over 8 h. CFU counts were measured every 2 h from three replicates per group.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques:

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: (A) GO enrichment analysis of A. baumannii A118 genes upregulated in response to serum at 4 HPI, within the Biological Process category. The X-axis represents the Signal value, and the Y-axis shows the GO term descriptions. GO terms were filtered using the following criteria: Term similarity ≥0.70, FDR ≤ 0.05, Signal ≥ 0.50, Strength ≥ 0.25, and Minimum count in the network was set to 10. (B) Heatmap showing 4 out of 18 acinetobactin operon genes upregulated in A. baumannii A118 in response to serum at 4 HPI (padj ≤ 0.05 and |log2foldchange| ≥ 1). (C) GO enrichment analysis of A. baumannii A118 genes downregulated in response to serum at 4 HPI, within the Biological Process category. The X-axis represents the Signal value, and the Y-axis shows the GO term descriptions. GO terms were filtered using the following criteria: Term similarity ≥0.70, FDR ≤ 0.05, Signal ≥ 0.50, Strength ≥ 0.25, and Minimum count in the network was set to 10.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques:

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: OMP profile of A. baumannii A118 grown in LB + 10% serum (lane 2) and LB (lane 3) for 4 h. Lane 1 shows molecular weight standards (kDa). The black arrow indicates the protein band excised from the SDS-PAGE gel and identified by LC–MS/MS.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques: Molecular Weight, SDS Page, Liquid Chromatography with Mass Spectroscopy

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: (A) GO enrichment analysis of A. baumannii A118 genes downregulated in response to serum at 8 HPI, within the Biological Process category. The X-axis represents the Signal value, and the Y-axis shows the GO term descriptions. GO terms were filtered using the following criteria: Term similarity ≥ 0.70, FDR ≤ 0.05, Signal ≥ 0.50, Strength ≥ 0.25, and Minimum count in the network was set to 10. (B) Heatmap showing 15 out of 18 acinetobactin operon genes as well as entA upregulated in A. baumannii A118 in response to serum at 8 HPI (padj ≤ 0.05 and |log2foldchange| ≥ 1).

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques:

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: Intracellular levels of all measured metal ions in A. baumannii A118 grown in LB + 10% serum were quantified using ICP-MS at 4 and 8 HPI. Error bars represent the standard deviations of triplicate samples.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques:

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: Quantitative analysis of biofilm formation by A. baumannii A118 and P. aeruginosa PAO1 in LB and LB supplemented with varying percentages of serum. Statistical significance ( p < 0.05) was determined by one-way ANOVA followed by Tukey’s multiple-comparison test. * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques: Comparison

Journal: Frontiers in Microbiology

Article Title: Transcriptomic and functional profiling of Acinetobacter baumannii reveals adaptation to burn patient blood and time-dependent responses to human serum

doi: 10.3389/fmicb.2025.1635690

Figure Lengend Snippet: Galleria mellonella infection assays showing differences in survival of larvae injected with 10 μL of a standardized suspension of A. baumannii A118 at a concentration of 1 × 10 5 CFU/mL, after growth in either LB or LB + 10% serum, compared to controls injected with sterile 1X PBS.

Article Snippet: Acinetobacter baumannii strain A118 was received from ATCC and used in all experiments.

Techniques: Infection, Injection, Suspension, Concentration Assay, Sterility

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Quantification of fhuE expression level and rifabutin activity against A. baumannii . (a) A. baumannii HUMC1 fhuE transcript levels were determined in different media by quantitative real-time PCR and normalized to the fhuE expression of the strain grown in CA-MHB. CA-MHB and RPMI media were supplemented with 0.1 mM pyridoxal isonicotinoyl hydrazone (PIH) or 10% (v/v) FCS, respectively. (b) Rifabutin activity on A. baumannii HUMC1 determined in CA-MHB supplemented with PIH. (c) Rifabutin activity determined in RPMI supplemented with 10% (v/v) FCS (black) and MHA supplemented with 0.1 mM PIH (white) on WT A. baumannii strains and their Δ fhuE mutants.

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Expressing, Activity Assay, Real-time Polymerase Chain Reaction

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Activity of rifabutin (black bars) and rifampicin (white bars) upon plasmid-mediated expression of (a) different FhuE variants determined in CA-MHB medium and (b) Arr-2 determined in RPMI supplemented with 10% FCS. A. baumannii ATCC-17978 was used as host strain; gene expression from plasmids was induced with 1 mM IPTG, and a plasmid that did not encode fhuE or arr-2 was used as control. *MIC >32 mg/L.

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Activity Assay, Plasmid Preparation, Expressing, Gene Expression, Control

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Comparison of the efficacy of rifabutin against 293 carbapenem-resistant clinical isolates of A. baumannii in two different media. (a) Cumulative susceptibility and (b) MIC distribution of rifabutin determined in IC-RPMI and IC-MHA .

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Comparison

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Cumulative susceptibility to rifabutin determined in IC-MHA against all A. baumannii isolates or by region and infection type

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Infection

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Cumulative susceptibility of rifabutin and comparator antibiotics against a panel of 293 carbapenem-resistant A. baumannii . Rifabutin MIC was determined in IC-MHA, whereas the MICs of meropenem, ceftazidime, minocycline, tigecycline, colistin, tobramycin and cefiderocol were determined according to CLSI guidelines.

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques:

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Overview of antimicrobial susceptibility of 293 clinical A. baumannii isolates and clinical classification according to EUCAST and CLSI guidelines

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques:

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Rifabutin shows strong activity against A. baumannii subpopulations resistant to different antibiotics

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Activity Assay

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Rifabutin activity determined in IC-RPMI on A. baumannii strains with active or disrupted rifabutin uptake. (a) Rifabutin MIC on WT strains encoding the FhuE LAC-4 variant (black bars) and their isogenic mutants where fhuE LAC-4 was chromosomally exchanged for the fhuE HUMC1 allele (white bars). Strain BV788 carries an RpoB H535Q mutation while strain LAC-4 does not carry additional resistance mechanisms. *MIC >32 mg/L. (b) Rifabutin MIC on WT strains encoding the FhuE HUMC1 variant (black bars) and their Δ fhuE isogenic mutants (white bars). Strains BV683, BV710, BV778 and BV845 carry RpoB mutations I581M, S583L, H535Q and N527D, respectively, and strain BV840 encodes Arr-2 inactivation enzyme. *MIC >32 mg/L.

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Activity Assay, Variant Assay, Mutagenesis

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Growth complementation of the A. baumannii mutant strain depleted for endogenous siderophore production to determine the ability of FhuE HUMC1 and FhuE LAC-4 variants to transport siderophores. A. baumannii ATCC 19798 Δ basD Δ fhuE double mutant strains complemented with (a) FhuE HUMC1 -expressing plasmid or (b) FhuE LAC-4 -expressing plasmid were grown in LB medium containing 225 μM 2,2-bipyridyl supplemented with 20 μM desferricoprogen (square), rhodotorulic acid (triangle), desferrioxamine B (inverted triangle) or no siderophores (circle), as previously described. A. baumannii ATCC 19798 Δ basD Δ fhuE double mutant strains complemented with an empty plasmid were used as controls (open symbols).

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Mutagenesis, Expressing, Plasmid Preparation

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: A. baumannii UNT091-1 mutational resistance frequencies towards rifabutin

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques: Concentration Assay

Journal: Journal of Antimicrobial Chemotherapy

Article Title: In vitro activity of rifabutin against 293 contemporary carbapenem-resistant Acinetobacter baumannii clinical isolates and characterization of rifabutin mode of action and resistance mechanisms

doi: 10.1093/jac/dkaa370

Figure Lengend Snippet: Model for rifabutin and rifampicin mode of action and resistance mechanisms in A. baumannii . This figure appears in colour in the online version of JAC and in black and white in the print version of JAC .

Article Snippet: A. baumannii isolates ( n = 293) used in this study were collected between 2017 and 2019 in various clinical laboratories from Europe ( n = 144), the USA ( n = 99) and Asia-West Pacific ( n = 50) regions (JMI Laboratories, North Liberty, IA, USA).

Techniques:

Journal: Antibiotics

Article Title: Pan-Drug Resistant Acinetobacter baumannii , but Not Other Strains, Are Resistant to the Bee Venom Peptide Melittin

doi: 10.3390/antibiotics9040178

Figure Lengend Snippet: The action of melittin on biofilms of A. baumannii strains. Bacteria were allowed to grow in 96-well plates; after 24 h, the biofilms were treated with melittin (142 µg/mL) and after 2 h the biofilms were quantified by staining with crystal violet. Control represents untreated groups. Results represent the mean and standard deviation of at least three independent experiments. **** Statistically significant ( p < 0.001) using t -test.

Article Snippet: Four A. baumannii strains were collected from two public hospitals in Rio de Janeiro: one (31852) that was susceptible to eleven antimicrobials tested of six groups, two (33677 and 96734) that harbor bla OXA−23 genes representing the two major clusters of XDR A. baumannii disseminated in Brazil— ST15/CC15 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst_abaumannii_isolates&id=3655 ) and ST79/CC79 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst abaumannii_isolates &id= 3647 )—according to the Pasteur Institute and one (100) PDR strain that displayed resistance to all antimicrobials tested, including polymyxin.

Techniques: Bacteria, Staining, Control, Standard Deviation

Journal: Antibiotics

Article Title: Pan-Drug Resistant Acinetobacter baumannii , but Not Other Strains, Are Resistant to the Bee Venom Peptide Melittin

doi: 10.3390/antibiotics9040178

Figure Lengend Snippet: Effect of melittin in bacterial membrane permeability. Different A. baumannii strains were treated with melittin (142 µg/mL) for 2 h or heat-treated at 65 °C for 15 min, then incubated with the nucleic acid probe propidium iodide (PI; 30 µM), as a membrane permeability indicator. Bars indicate the percentage of PI fluorescent bacteria in the untreated group, treated with melittin or heat-treated. Results represent the mean and standard deviation. Statistically different (* p < 0.05, ** p < 0.01 and **** p < 0.001) from melittin group using t -test.

Article Snippet: Four A. baumannii strains were collected from two public hospitals in Rio de Janeiro: one (31852) that was susceptible to eleven antimicrobials tested of six groups, two (33677 and 96734) that harbor bla OXA−23 genes representing the two major clusters of XDR A. baumannii disseminated in Brazil— ST15/CC15 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst_abaumannii_isolates&id=3655 ) and ST79/CC79 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst abaumannii_isolates &id= 3647 )—according to the Pasteur Institute and one (100) PDR strain that displayed resistance to all antimicrobials tested, including polymyxin.

Techniques: Membrane, Permeability, Incubation, Bacteria, Standard Deviation

Journal: Antibiotics

Article Title: Pan-Drug Resistant Acinetobacter baumannii , but Not Other Strains, Are Resistant to the Bee Venom Peptide Melittin

doi: 10.3390/antibiotics9040178

Figure Lengend Snippet: Fluorescence images of CFSE stained A. baumannii after treatment with melittin (142 µg/mL) for 2 h at 37 °C. The proliferation of untreated bacteria ( A ) and bacteriostatic effect of melittin against ATCC strain ( B ). A. baumannii PDR strain 100 images of CFSE-labeled bacteria from untreated ( C ) and melittin treated cells ( D ). DIC: Differential interference contrast. Bar = 20 μm.

Article Snippet: Four A. baumannii strains were collected from two public hospitals in Rio de Janeiro: one (31852) that was susceptible to eleven antimicrobials tested of six groups, two (33677 and 96734) that harbor bla OXA−23 genes representing the two major clusters of XDR A. baumannii disseminated in Brazil— ST15/CC15 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst_abaumannii_isolates&id=3655 ) and ST79/CC79 ( https://pubmlst.org/bigsdb?page=info&db=pubmlst abaumannii_isolates &id= 3647 )—according to the Pasteur Institute and one (100) PDR strain that displayed resistance to all antimicrobials tested, including polymyxin.

Techniques: Fluorescence, Staining, Bacteria, Labeling