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.

Physicochemical Characterization and In-Vitro Antimicrobial Activity of Chitosan Extracted from Shrimp Shells Waste from Beni Saf Sea, Algeria

2018 ◽  
Vol 7 (3) ◽  
pp. 122-129
Author(s):  
Fatma Youcefi ◽  
Ali Riazi ◽  
Meriem Mokhtar ◽  
Tefiani Choukri ◽  
Khaouani Naima
Keyword(s):  
Antimicrobial Activity ◽  
Physicochemical Characterization ◽  
Organic Polymer ◽  
In Vitro Antimicrobial Activity ◽  
Physiochemical Parameters ◽  
Microdilution Method ◽  
Molecular Arrangement ◽  
Shrimp Shells ◽  
Broth Microdilution Method

Chitosan is the most abundant natural organic polymer in nature. Its positive charge and its molecular arrangement confer interesting properties on the plane food, pharmaceutical, medical, cosmetic, water treatment. The present study was undertaken to study the physiochemical parameters and the in vitro antimicrobial activity of chitosan extracted from shrimp shells waste. The molecular weight of chitosan is 1414.33±16.99 kDa with, the percent of Ash 0,345±0,040 %, moisture is 2,98 ±0,13 % , and protein is 0.3 ±0,041 %.Chitosan produced (5 %) was also characterized with Fourier Transform Infrared Spectroscopy (FTIR) the spectrum of the chitosan sample from the shell recorded 16 peaks in the range of 689.40/cm and 3430.02 /cm. The antibacterial and antifungul activities of chitosan were examined against Escherichia coli ATCC10536, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes ATCC7644, Staphylococcus aureus ATCC29213, Aspergillus niger ATCC 16888 and Candida albicans ATCC 10231 by agar wells diffusion the tests inhibitions zones diameters were 49,74± 0,75 , 54,35±0,93 , 42,27±1,07 , 32,95±0,28 and 53,73±0,64mm respectively. The minimum inhibitory concentration (MIC) using a broth microdilution method against tested microorganisms was ranging from 008% to 1.22%. These results open interesting perspectives of the chitosan. It can be used as new biomaterial with utility in many industrial areas.

scholarly journals In vitro Evaluation of Antimicrobial Activity of Opuntia ficus-indica Seed Oil

2021 ◽  
pp. 490-496
Author(s):  
Naz Fathima Raj Mohamed ◽  
R. V. Geetha ◽  
P. Sankar Ganesh
Keyword(s):  
Antimicrobial Activity ◽  
Streptococcus Mutans ◽  
Seed Oil ◽  
Unsaturated Fatty Acids ◽  
Broth Microdilution ◽  
Opuntia Ficus Indica ◽  
Food Ingredients ◽  
Study Results ◽  
Broth Microdilution Method

Introduction: Opuntia ficus-indica is a well adapted cactus to extreme climatic environments. In the usual diet and food industry, it is an interesting source of food ingredients. In general, the protective role of prickly pears has been due to their antioxidant components, phenolic compounds, and some minor components present in the content of seed oil and seed protein and the oil from cactus pear seed has been found with high levels of unsaturated fatty acids ,with antioxidant  and antimicrobial activity as well as cardioprotective, antithrombotic, anti-inflammatory, antiarrhythmic, hypolipidemic, and antihyperglycemic effect. Aim: To evaluate the in vitro antimicrobial activity of Opuntia ficus-indica seed oil against Streptococcus mutans. Materials and Methods: Broth microdilution assay was performed by following modifications: Brain heart infusion (BHI) broth was prepared and sterilise at 121c for 15lbs, the 100 microlitre of streptococcus mutans inoculated at freshly prepared broth and incubated at 37c for 24 hours. Then BHI broth prepared with sucrose and serial two fold dilution were done with 160microlitre broth and 40 microlitre prickly pear seed oil. Then 20 microlitre of culture was added. Column 11 contains BHI using sterile micro pipettes and the plates were incubated at 30 c for 18 hours. The growth of bacteria was visualised and lowest concentration with no visible growth was recorded as MIC. Results: This study results shows that, by broth microdilution method at concentration ranging from 10%-0.039% v/v, Opuntia ficus-indica seed oil potentially inhibits the growth of streptococcus mutans at the concentration of 0.03% (v/v). Conclusion: From the study, the results demonstrated that Opuntia ficus-indica seed oil shows noticeable antimicrobial activity against streptococcus mutans. Use of essential oils against oral pathogens can be an alternative to other antimicrobial agents which could be cheap and effective modules used in control of bacteria which are responsible for oral infections.

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