scholarly journals In vitro activity and mode of action of diastereomeric antimicrobial peptides against bacterial clinical isolates

2004 ◽  
Vol 53 (2) ◽  
pp. 230-239 ◽  
Author(s):  
U. Pag
Keyword(s):  
Antimicrobial Peptides ◽  
Mode Of Action ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity

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

2020 ◽  
Vol 75 (12) ◽  
pp. 3552-3562
Author(s):  
Vincent Trebosc ◽  
Birgit Schellhorn ◽  
Julian Schill ◽  
Valentina Lucchini ◽  
Jacqueline Bühler ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Mode Of Action ◽  
Resistance Mechanisms ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Oral Drug ◽  
In Vitro Activity ◽  
Carbapenem Resistant ◽  
The Usa

Abstract Background Rifabutin, an oral drug approved to treat Mycobacterium avium infections, demonstrated potent activity against Acinetobacter baumannii in nutrient-limited medium enabled by rifabutin cellular uptake through the siderophore receptor FhuE. Objectives To determine rifabutin in vitro activity and resistance mechanisms in a large panel of A. baumannii isolates. Methods Two hundred and ninety-three carbapenem-resistant A. baumannii clinical isolates collected from Europe, the USA and Asia during 2017–19 were used for MIC determination. Sequencing/genotyping of fhuE, rpoB and arr-2 genes in isolates with elevated rifabutin MIC combined with genetic engineering and gene expression quantification was used to characterize rifabutin’s mode of action and resistance mechanisms. Results Rifabutin showed excellent activity on the strain panel, with an MIC50/90 of 0.008/1 mg/L, and was superior to all other antibiotics tested, including colistin, tigecycline and cefiderocol (MIC90 of 8 mg/L). Rifabutin remained active on resistant subpopulations, including strains resistant to the siderophore–drug conjugate cefiderocol (MIC90 of 2 mg/L, n = 23). At least two independent resistance mechanisms were required to abolish rifabutin activity, which is in line with the dose-dependent mutational resistance frequency reaching 10−9 at rifabutin concentrations at or above 2 mg/L. Conclusions This study demonstrated the potent activity of rifabutin against carbapenem-resistant A. baumannii. We propose that FhuE-mediated active uptake of rifabutin enables activity against rifampicin-resistant isolates. To achieve clinically meaningful strain coverage and to avoid rapid resistance development, rifabutin concentrations ≥2 mg/L are required, something rifabutin oral formulations cannot deliver.

scholarly journals In vitro activity of 12 antimicrobial peptides against Mycobacterium tuberculosis and Mycobacterium avium clinical isolates

2019 ◽  
Vol 68 (2) ◽  
pp. 211-215 ◽  
Author(s):  
Elena Portell-Buj ◽  
Andrea Vergara ◽  
Izaskun Alejo ◽  
Alexandre López-Gavín ◽  
Maria Rosa Monté ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Antimicrobial Peptides ◽  
Mycobacterium Avium ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity

scholarly journals 1280. In-Vitro Activity of Cefiderocol, Imipenem/Relebactam, & Ceftazidime/Avibactam in Ceftolozane/Tazobactam Resistant Strains of Multidrug Resistant Pseudomonas aeruginosa

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S655-S655
Author(s):  
Daniel Navas ◽  
Angela Charles ◽  
Amy Carr ◽  
Jose Alexander
Keyword(s):  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Resistance Testing ◽  
Clinical Samples ◽  
In Vitro Activity ◽  
Carbapenemase Gene ◽  
Resistant Strains

Abstract Background The activity of imipenem/relebactam (I/R), ceftazidime/avibactam (CZA) and cefiderocol (FDC) were evaluated against clinical isolates of multidrug resistant (MDR) strains of P. aeruginosa which was resistant to ceftolozane/tazobactam (C/T). The recent increase of MDR P. aeruginosa strains isolated from clinical samples has prompted research and development of new antimicrobials that can withstand its multiple resistance mechanisms. C/T is an effective option for treatment of MDR P. aeruginosa in our facility with only 10% of resistance in MDR strains, but the emergence of resistance may occur due to the presence of a carbapenemase gene or an ampC mutation. Methods Antimicrobial susceptibility testing for C/T Etest® (bioMérieux, Inc.) were performed on all MDR strains initially screened by the VITEK2® (bioMérieux, Inc.). 10% (n=20) of all MDR isolates were resistant to C/T by the CLSI 2019 breakpoints. These resistant isolates were tested for presence of a carbapenemase gene using the GeneXpert CARBA-R (Cepheid®) PCR and against CZA Etest® (bioMérieux, Inc.) I/R gradient strips (Liofilchem®) and FDC broth microdilution (Thermo Scientific™ Sensititre™). Results A total of 20 clinical isolates of MDR P. aeruginosa resistant to C/T were tested following standardized CLSI protocols and techniques. All 20 isolates were screened for the presence of a carbapenemase gene (blaVIM, blaNDM, blaKPC, blaOXA-48, blaIMP). A blaVIM gene was detected in 6 (30%) out of 20 isolates. FDC demonstrated the greatest activity with 85% (n=17) of susceptible isolates (CLSI MIC <4µg/dL). CZA (CLSI MIC <8µg/dL) and I/R (FDA MIC <2µg/dL) showed 15% (n=3) and 10% (n=2) of susceptible isolates respectively. FDC was active against all 6 blaVIM isolates, where all 6 strains were resistant to CZA and I/R as expected. 3 isolates tested non-susceptible against FDC; additional characterization was not performed at this time. Conclusion Based on these results, FDC demonstrated the greatest in-vitro activity against C/T resistant strains of MDR P. aeruginosa. FDC also demonstrated activity against all 6 MDR P. aeruginosa carrying blaVIM gene. FDC is a strong option to consider on MDR P. aeruginosa strains based on a resistance testing algorithm and a cost/effective protocol. Disclosures All Authors: No reported disclosures

In vitro activity of olorofim against clinical isolates of the Fusarium oxysporum and Fusarium solani species complexes

Mycoses ◽  
2021 ◽  
Author(s):  
Hamid Badali ◽  
Connie Cañete‐Gibas ◽  
Hoja Patterson ◽  
Carmita Sanders ◽  
Barbara Mermella ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Solani ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Species Complexes

scholarly journals In Vitro Activity of Posaconazole against Clinical Isolates of Dermatophytes

2001 ◽  
Vol 39 (11) ◽  
pp. 4208-4209 ◽  
Author(s):  
F. Barchiesi ◽  
D. Arzeni ◽  
V. Camiletti ◽  
O. Simonetti ◽  
A. Cellini ◽  
...  
Keyword(s):  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity
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