scholarly journals Antimicrobial Activity of Combined Cinnamon Nanoemulsions-Antibiotics against Acinetobacter baumannii

2019 ◽  
Vol 1 (2) ◽  
pp. 1-4
Author(s):  
Dana Sabir ◽  
Karzan Sidiq
Keyword(s):  
Antimicrobial Activity ◽  
Acinetobacter Baumannii

scholarly journals In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1309
Author(s):  
Davide Carcione ◽  
Claudia Siracusa ◽  
Adela Sulejmani ◽  
Roberta Migliavacca ◽  
Alessandra Mercato ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Acinetobacter Baumannii ◽  
Inhibition Zone ◽  
Broth Microdilution ◽  
Large Variability ◽  
Gold Standard Method ◽  
Disk Diffusion Test ◽  
In Vitro Antimicrobial Activity ◽  
Broth Microdilution Method

Background: Cefiderocol is a siderophore cephalosporin that exhibits antimicrobial activity against most multi-drug resistant Gram-negative bacteria, including Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. Methods: A total of 20 multidrug-resistant A. baumannii strains were isolated from 2020 to 2021, molecularly characterized and tested to assess the in vitro antibacterial activity of cefiderocol. Thirteen strains were carbapenem-hydrolysing oxacillinase OXA-23-like producers, while seven were non-OXA-23-like producers. Minimum inhibitory concentrations (MICs) were determined by broth microdilution, considered as the gold standard method. Disk diffusion test was also carried out using iron-depleted CAMHB plates for cefiderocol. Results: Cefiderocol MICs ranged from 0.5 to 1 mg/L for OXA-23-like non-producing A. baumannii strains and from 0.25 to >32 mg/L for OXA-23-like producers, using the broth microdilution method. Cefiderocol MIC90 was 8 mg/L. Diameter of inhibition zone of cefiderocol ranged from 18 to 25 mm for OXA-23-like non-producers and from 15 to 36 mm for OXA-23-like producers, using the diffusion disk method. A large variability and a low reproducibility were observed during the determination of diameter inhibition zone. Molecular characterization showed that all isolates presented the ISAba1 genetic element upstream the blaOXA-51. Among OXA-23-like non-producers, four were blaOXA-58 positive and two were negative for all the resistance determinants analyzed. Conclusions: Cefiderocol showed in vitro antimicrobial activity against both carbapenem-susceptible and non-susceptible A. baumannii strains, although some OXA-23-like producers were resistant. Further clinical studies are needed to consolidate the role of cefiderocol as an antibiotic against MDR A. baumannii.

Antimicrobial activity of novel chalcones and modulation of virulence factors in hospital strains of Acinetobacter baumannii and Pseudomonas aeruginosa

2019 ◽  
Vol 131 ◽  
pp. 186-196 ◽  
Author(s):  
Dušan Ušjak ◽  
Branka Ivković ◽  
Dragana D. Božić ◽  
Lidija Bošković ◽  
Marina Milenković
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Acinetobacter Baumannii ◽  
Virulence Factors

scholarly journals A Systematic Study of the Stability, Safety, and Efficacy of the de novo Designed Antimicrobial Peptide PepD2 and Its Modified Derivatives Against Acinetobacter baumannii

2021 ◽  
Vol 12 ◽  
Author(s):  
Sung-Pang Chen ◽  
Eric H-L Chen ◽  
Sheng-Yung Yang ◽  
Pin-Shin Kuo ◽  
Hau-Ming Jan ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptide ◽  
Acinetobacter Baumannii ◽  
De Novo ◽  
Multidrug Resistant ◽  
Hek293 Cells ◽  
Amino Acid Residues ◽  
Bacteria And Fungi ◽  
The Stability

Searching for new antimicrobials is a pressing issue to conquer the emergence of multidrug-resistant (MDR) bacteria and fungi. Antimicrobial peptides (AMPs) usually have antimicrobial mechanisms different from those of traditional antibiotics and bring new hope in the discovery of new antimicrobials. In addition to antimicrobial activity, stability and target selectivity are important concerns to decide whether an antimicrobial peptide can be applied in vivo. Here, we used a simple de novo designed peptide, pepD2, which contains only three kinds of amino acid residues (W, K, L), as an example to evaluate how the residues and modifications affect the antimicrobial activity against Acinetobacter baumannii, stability in plasma, and toxicity to human HEK293 cells. We found that pepI2 with a Leu→Ile substitution can decrease the minimum bactericidal concentrations (MBC) against A. baumannii by one half (4 μg/mL). A D-form peptide, pepdD2, in which the D-enantiomers replaced the L-enantiomers of the Lys(K) and Leu(L) residues, extended the peptide half-life in plasma by more than 12-fold. PepD3 is 3-residue shorter than pepD2. Decreasing peptide length did not affect antimicrobial activity but increased the IC50 to HEK293 cells, thus increased the selectivity index (SI) between A. baumannii and HEK293 cells from 4.7 to 8.5. The chain length increase of the N-terminal acyl group and the Lys→Arg substitution greatly enhanced the hemolytic activity, hence those modifications are not good for clinical application. Unlike colistin, the action mechanism of our peptides relies on negatively charged lipids rather than lipopolysaccharides. Therefore, not only gram-negative bacteria but also gram-positive bacteria can be killed by our peptides.

scholarly journals STUDY OF IRON OXIDE NANOPARTICLES DOPED WITH COPPER: ANTIMICROBAL AND PHOTOCATALYTICAL ACTIVITY

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Aleksandra Šmitran ◽  
Dijana Jelić ◽  
Sanja Pržulj ◽  
Savka Vračević ◽  
Dragana Gajić ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Iron Oxide ◽  
Antimicrobial Resistance ◽  
Acinetobacter Baumannii ◽  
Iron Oxide Nanoparticles ◽  
Copper Ions ◽  
Technological Development ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Oxide Nanoparticles

Last decade is designated as the postantibiotic era due to increasing number of resistant and multiresistant strains of microorganisms, which developed resistance to one or more antibiotics. Antimicrobial resistance becomes a global health problem. This phenomenon of antimicrobial resistance will undoubtedly affect the efficiency and use of antibiotics in the future. Science and technological development are committed to researching and developing new antibiotics that will satisfy the missing criteria and address the problem of antimicrobial resistance. One of the possible solutions lies in nanotechnologies. Nanoparticles have been isolated as one of the most promising substances on which microorganisms rarely or even develop mechanisms of resistance. The nanoparticles may be in conjunction with already existing antibiotics structures and contribute to the improvement of physicochemical properties in order to successfully overcome the mechanism of antimicrobial resistance. By designing nanoparticles with proper physicochemical and biochemical characteristics we determine their application. The aim of this research is to dope synthesized iron oxide nanoparticles with copper ions in order to test their antimicrobial activity and to evaluate their use as potential antimicrobial agent. Extracts of green tea and ascorbic acid were used as reduction agent for the iron oxide nanoparticles doped with Cu. The antimicrobial activity of the synthesized nanoparticles on the isolates Acinetobacter baumannii and methicillin resistant Staphylococcus aureus (MRSA) was performed by the agar well diffusion method. Synthesized iron oxide nanoparticles showed activity against Acinetobacter baumannii with inhibition zone around 12 mm. Photocatalytical activity was also evaluated by UV/VIS spectrophotometry. Samples doped with copper showed much better photocatalytical performances.

scholarly journals Design of Novel Amphipathic α-Helical Antimicrobial Peptides with No Toxicity as Therapeutics against the Antibiotic-Resistant Gram-Negative Bacterial Pathogen, Acinetobacter Baumannii

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Mant CT ◽  
Jiang Z ◽  
Gera L ◽  
Davis T ◽  
Hodges RS
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Acinetobacter Baumannii ◽  
De Novo ◽  
Bacterial Pathogen ◽  
Polymyxin B ◽  
Hemolysis Assay ◽  
Charged Residues ◽  
Positively Charged ◽  
Specificity Determinants

We designed de novo and synthesized two series of five 26-residue amphipathic α-helical cationic antimicrobial peptides (AMPs) with five or six positively charged residues (D-Lys, L-Dab (2,4-diaminobutyric acid) or L-Dap (2,3-diaminopropionic acid)) on the polar face where all other residues are in the D-conformation. Hemolytic activity against human red blood cells was determined using the most stringent conditions for the hemolysis assay, 18h at 37°C, 1% human erythrocytes and peptide concentrations up to 1000 μg/mL (~380 μM). Antimicrobial activity was determined against 7 Acinetobacter baumannii strains, resistant to polymyxin B and colistin (antibiotics of last resort) to show the effect of positively charged residues in two different locations on the polar face (positions 3, 7, 11, 18, 22 and 26 versus positions 3, 7, 14, 15, 22 and 26). All 10 peptides had two D-Lys residues in the center of the non-polar face as “specificity determinants” at positions 13 and 16 which provide specificity for prokaryotic cells over eukaryotic cells. Specificity determinants also maintain excellent antimicrobial activity in the presence of human sera. This study shows that the location and type of positively charged residue (Dab and Dap) on the polar face are critical to obtain the best therapeutic indices.

scholarly journals Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii

2018 ◽  
Vol 11 (1) ◽  
pp. 317-324 ◽  
Author(s):  
Maciej Jaśkiewicz ◽  
Damian Neubauer ◽  
Kamil Kazor ◽  
Sylwia Bartoszewska ◽  
Wojciech Kamysz
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Acinetobacter Baumannii ◽  
Reference Strain ◽  
Inhibitory Concentration ◽  
Wide Spectrum ◽  
Selectivity Index ◽  
Planktonic Culture

Abstract Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.

Sign in / Sign up

Export Citation Format

Share Document