Minimum-inhibitory-concentration of iclaprim and lefamulin against Mycobacterium abscessus complex

2021 ◽  
Author(s):  
Ka Lip Chew ◽  
Sophie Octavia ◽  
Siang Fei Yeoh ◽  
Jeanette W.P. Teo
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Mycobacterium Abscessus ◽  
Mycobacterium Abscessus Complex

Infections with rapid-growing-mycobacteria (RGM) are often difficult to treat.…

scholarly journals In Vitro Synergism of Rifabutin with Clarithromycin, Imipenem, and Tigecycline against the Mycobacterium abscessus Complex

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Aristine Cheng ◽  
Yi-Tzu Tsai ◽  
Shu-Yuan Chang ◽  
Hsin-Yun Sun ◽  
Un-In Wu ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Mycobacterium Abscessus ◽  
First Line ◽  
Content Type ◽  
Mycobacterium Abscessus Complex ◽  
Potential Synergy ◽  
Resistant Strains ◽  
Reference Strains

ABSTRACT Infections caused by the difficult-to-treat bacterium Mycobacterium abscessus are increasing in frequency. Rifabutin, in contrast to rifampin, appears to be active in vitro against M. abscessus, especially against clarithromycin-resistant strains. However, explorations for potential synergy between rifabutin and available antimicrobials are currently limited. In vitro synergism between rifabutin and 10 antimicrobials was evaluated in 31 mycobacterial strains by the checkerboard method. The fractional inhibitory concentration index (FICI) was calculated for each rifabutin-based combination. The colony morphology was recorded. Molecular methods for determination of the M. abscessus subspecies and analysis of macrolide resistance were performed by sequencing of the secA1, rpoB, hsp65, erm(41), and rrl genes. Rifabutin yielded an MIC50 of 16 mg/liter (range, 2 to 32 mg/liter) against 26 clinical M. abscessus isolates (comprising 13 M. abscessus subsp. abscessus and 13 M. abscessus subsp. massiliense isolates) and 5 reference strains, including M. abscessus subsp. abscessus ATCC 19977, M. abscessus subsp. bolletii BCRC 16915, M. abscessus subsp. massiliense BCRC 16916, M. chelonae ATCC 35752, and M. peregrinum ATCC 700686. Significant synergism, classified by an FICI of ≤0.5, was demonstrated for the combinations of rifabutin and imipenem in 100% of M. abscessus subsp. abscessus and 69% of M. abscessus subsp. massiliense isolates, and significant synergism for rifabutin and tigecycline was demonstrated in 77% of M. abscessus subsp. abscessus and 69% of M. abscessus subsp. massiliense isolates. Among the 6 clarithromycin-resistant (MICs ≥ 8 mg/liter) M. abscessus subsp. abscessus isolates, the combination of rifabutin and clarithromycin was 100% synergistic. Rifabutin showed promising in vitro synergism with first-line anti-M. abscessus agents, especially for macrolide-resistant M. abscessus subsp. abscessus isolates.

Green and Simple Synthesis of Silver Nanoparticles by Aqueous Extract of Perovskia abrotanoides: Characterization, Optimization and Antimicrobial Activity

2020 ◽  
Vol 21 (11) ◽  
pp. 1129-1137 ◽  
Author(s):  
Somayeh Mirsadeghi ◽  
Masoumeh F. Koudehi ◽  
Hamid R. Rajabi ◽  
Seied M. Pourmortazavi
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Plant Extract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Extraction Temperature ◽  
Silver Particles ◽  
Silver Nps ◽  
Perovskia Abrotanoides

Background: Herein, we report the biosynthesis procedure to prepare silver nanoparticles as reduction and capping agents with the aqueous plant extract of Perovskia abrotanoides. Methods: The therapeutic application of silver nanoparticles entirely depends on the size and shape of the nanoparticles therefore, their control during the synthesis procedure is so important. The effects of synthesis factors, for example, silver ion concentration, the mass of plant extract, reaction time and extraction temperature, on the size of silver particles were considered and optimized. Several analytical methods were used for the characterization of silver NPs including FT-IR and UV–Vis spectrophotometer, XRD and SEM. Results: The results showed that the mean size of the silver particles was about 51 nm. Moreover, the antibacterial properties of biosynthesized silver NPs were investigated by the minimum inhibitory concentration, minimum bactericidal concentration, and Well-diffusion tests. The minimum inhibitory concentration/ minimum bactericidal concentration values of silver NPs and aqueous plant extract versus Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (E. coli) were 3.03/0.00, 1.20/0.01, 3.06/0.00, 0.98/1.04, 1.00/0.05 and 1.30/0.03 (mg/mL), respectively. Conclusion: The antimicrobial activity study displayed that the synthesized silver nanoparticles by plant extract have better antimicrobial properties compared to aqueous plant extract of Perovskia abrotanoides.

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