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

Journal: Science Advances

Article Title: Growth productivity as a determinant of the inoculum effect for bactericidal antibiotics

doi: 10.1126/sciadv.add0924

Figure Lengend Snippet: ( A ) ΔMIC kan as a function of % glucose y for A. faecalis , P. aeruginosa , and E. coli (from Fig. 2B ). SD from ≥3 biological replicates. For (A) and (B), SD from ≥4 different percentages of casamino acids per percentage of glucose. Raw data in fig. S10. Average residuals for growth curve fitting in table S3. ( B ) ΔMIC kan as a function of growth productivity. *ΔMIC kan not greater than zero (* P = 0.09, ** P = 0.20, one-tailed t tests). P and R 2 values on the figure from a linear regression. Shading denotes 95% confidence interval. Trends were significant using a Deming regression (table S10) and a WLS regression (table S11). Error bars: x axis = standard error from linear regression used to determine growth productivity, y axis = SD. Raw growth productivity data in fig. S10A. ( C ) ΔMIC kan as function of growth productivity for multiple bacterial species. Glucose = 0.04%. AB = A. baumannii , EC = E. coli , KP = K. pneumoniae , AF = A. faecalis , and PA = P. aeruginosa . We did not find a significant linear correlation between ΔMIC kan and [ATP] or maximum growth rate for P. aeruginosa and A. faecalis . Error bars: x axis = standard error from linear regression used to determine growth productivity, y axis = SD. We did not find a significant linear correlation between ΔMIC kan and [ATP] or maximum growth rate when all species were considered (glucose = 0.04%; fig. S10 and SM Results).

Article Snippet: P. aeruginosa strain PA14, K. pneumoniae strain (Carolina Biological, Burlington, NC), A. baumannii strain 5-109 (Carolina Biological), and A. faecalis (Carolina Biological) were used where indicated.

Techniques: One-tailed Test

Journal: Antibiotics

Article Title: Exploring Roles of the Polysaccharide Capsule in Pathogenesis of Hypervirulent Acinetobacter baumannii Clinical Isolate Lac-4

doi: 10.3390/antibiotics13010010

Figure Lengend Snippet: Gene deletion strategy: ( A ) Schematic depicting capsule locus (K Locus) for Acinetobacter baumannii Ab Lac-4. ( B ) Representative images showing the impact of capsule loss on buoyancy and growth on tryptic soy agar (TSA). Ab Lac-4 WT, wza #, and wza -Rev were grown to stationary phase and allowed to stand at RT for 3 h. ( C ) Turbidity (OD 600 ) of the liquid cultures; three independent experiments pooled. n.s. = not significant, **** p < 0.0001. ( D ) Growth curves from Ab Lac-4, wza #, and wza -Rev grown in tryptic soy broth (THB). Three independent experiments were pooled.

Article Snippet: The A. baumannii strain Lac-4 was obtained from Wangxue Chen (National Research Council, Ottowa, ON, Canada).

Techniques: