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

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.

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Evaluation in vitro of antimicrobial activity of tucumã oil (Astrocaryum Vulgare)

Archives in Biosciences & Health ◽

10.18593/abh.19701 ◽

2019 ◽

Vol 1 (1) ◽

pp. 99-112 ◽

Cited By ~ 1

Author(s):

Aline Rossato ◽

Larissa da Silva Silveira ◽

Leonardo Quintana Soares Lopes ◽

Walter Paixão De Sousa Filho ◽

Larissa Finger Schaffer ◽

...

Keyword(s):

Antimicrobial Activity ◽

Staphylococcus Epidermidis ◽

Inhibitory Concentration ◽

Major Health Problem ◽

Major Health ◽

Gram Positive Bacteria ◽

Palm Trees ◽

The Family

Hospital Infection is a major health problem and affects around 1.5 million people annually around the world. The Amazon region has a wide diversity of native palm trees that have fruits and oilseeds. Astrocaryum vulgare, commonly known as Tucumã in Brazil, belongs to the family Arecaceae. This palm has orange, fleshy, single-egg-shaped fruits that are used for therapeutic purposes in diseases of the eyes and skin due to the high content of carotenoids, oil is used in cooking, health treatment and massage. This study evaluated the antimicrobial activity of the Tucumã oil against 18 microorganisms. The antimicrobial activity of Tucumã was measured through the determination of the Minimum Inhibitory Concentration (MIC), as well as the determination of the Minimum Microbicidal Concentration (CMM) aiming to contribute to the discovery of new antimicrobials against pathogenic microorganisms’ human health and may contribute to the treatment of nosocomial infections. The results showed that the oil of Tucumã presented antimicrobial activity against five important bacteria, four Gram - positive bacteria (Enterococcus faecalis, Enterococcus faecium, Staphylococcus epidermidis and Streptococcus agalactiae) and one Gram - negative (Acinetobacter baumannii).

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Antimicrobial Mechanisms of Leucocyte- and Platelet Rich Fibrin Exudate Against Planktonic Porphyromonas gingivalis and Within Multi-Species Biofilm: A Pilot Study

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.722499 ◽

2021 ◽

Vol 11 ◽

Author(s):

Fabio Rodríguez Sánchez ◽

Tim Verspecht ◽

Ana B. Castro ◽

Martine Pauwels ◽

Carlos Rodríguez Andrés ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Antimicrobial Activity ◽

Pilot Study ◽

Antimicrobial Peptides ◽

Porphyromonas Gingivalis ◽

Agar Plate ◽

Antimicrobial Effect ◽

Planktonic Culture ◽

Platelet Rich Fibrin

Leucocyte- and platelet rich fibrin (L-PRF) is an autologous biomaterial used in regenerative procedures. It has an antimicrobial activity against P. gingivalis although the mechanism is not fully understood. It was hypothesized that L-PRF exudate releases hydrogen peroxide and antimicrobial peptides that inhibit P. gingivalis growth. Agar plate and planktonic culture experiments showed that the antimicrobial effect of L-PRF exudate against P. gingivalis was supressed by peroxidase or pepsin exposure. In developing multi-species biofilms, the antimicrobial effect of L-PRF exudate was blocked only by peroxidase, increasing P. gingivalis growth with 1.3 log genome equivalents. However, no effect was shown on other bacteria. Pre-formed multi-species biofilm trials showed no antimicrobial effect of L-PRF exudate against P. gingivalis or other species. Our findings showed that L-PRF exudate may release peroxide and peptides, which may be responsible for its antimicrobial effect against P. gingivalis. In addition, L-PRF exudate had an antimicrobial effect against P. gingivalis in an in vitro developing multi-species biofilm.

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Evaluation of polysaccharides content in fruit bodies and their antimicrobial activity of four Ganoderma lucidum (W Curt.: Fr.) P. Karst. strains cultivated on different wood type substrates

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2012.001 ◽

2012 ◽

Vol 81 (1) ◽

pp. 17-21 ◽

Cited By ~ 27

Author(s):

Krystyna Skalicka-Woźniak ◽

Janusz Szypowski ◽

Renata Łoś ◽

Marek Siwulski ◽

Krzysztof Sobieralski ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Quantitative Determination ◽

Ganoderma Lucidum ◽

Inhibitory Concentration ◽

Micrococcus Luteus ◽

Dry Weight ◽

Bacterial Strains

Quantitative determination of polysaccharides in Ganoderma lucidum fruit bodies from different sawdust cultivation substrates and their antibacterial activity was done. Thirty six samples were analyzed. Four strains of Ganoderma lucidum (GL01, GL02, GL03 and GL04) were cultivated on the growth substrates of three different sawdust types: birch (Bo), maple (Kl) or alder (Ol) amended with wheat bran in three different concentrations: 10, 20 and 30% (w/w). Even though the richest in polysaccharides was GL01 strain, the highest yields of the polysaccharides were determined in GL04Kl3 sample and was 112.82 mg/g of dry weight. The antibacterial activity of polysaccharides was determined in vitro using micro-dilution broth method. The panel of eight reference bacterial strains was used. All the polysaccharide samples tested showed the broad spectrum and the moderate antibacterial activity. Micrococcus luteus ATCC 10240 strain was the most sensitive with MIC (minimal inhibitory concentration) = 0.63 − 1.25 mg/mL.

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Dibasic Esters of ortho-/meta-Alkoxyphenylcarbamic Acid Containing 1-Dipropylamino-3-Piperidinopropan-1-yl and Their Antimicrobial Activity

Polish Journal of Microbiology ◽

10.33073/pjm-2014-030 ◽

2014 ◽

Vol 63 (2) ◽

pp. 231-236

Author(s):

JOZEF CSÖLLEI ◽

IVAN MALÍK ◽

MARIÁN BUKOVSKÝ ◽

EVA SEDLÁROVÁ

Keyword(s):

Antimicrobial Activity ◽

Inhibitory Concentration ◽

Side Chain ◽

In Vitro Susceptibility ◽

E Coli ◽

Microdilution Method ◽

Quantitative Screening ◽

Significant Disease

In Europe, the presence of microorganisms that have become resistant to antimicrobials as the most significant disease threat has remained. The aim of the current research was to screen the in vitro susceptibility of Staphylococcus aureus, Escherichia coli and Candida albicans to the series of dibasic esters of ortho-/meta-alkoxyphenylcarbamic acid previously known for their local anaesthetic effectiveness and to contribute for the structure - antimicrobial potency relationships study within that class of the compounds. The antimicrobial activity investigation involved determination of the minimum inhibitory concentration (MIC) by applying the microdilution method; quantitative screening was performed on a blood agar (S. aureus), Endo agar (E. coli) or on Sabouraud's agar (C. albicans). The activity against all the microorganisms tested was primarily influenced by the position of alkoxy side chain attached to lipophilic aromatic ring and by its length as well. Inspected meta-alkoxy substituted derivatives have shown higher efficiency against all chosen microorganisms than their ortho-alkoxy positional isomers. The most promising results were observed when investigating the activity of meta-alkoxy substituted molecules against E. coli with the estimated MICs in the range of 12-49 microg/ml. Furthermore, such potency was found to be quasi parabolically dependent on alkoxy chain length achieving a maximum for meta-hexyloxy derivative which has shown MIC= 12 microg/ml. Considered compound was also regarded as the most effective against S. aureus with MIC = 98 microg/ml. Evaluating the potency against C. albicans, it was revealed that no molecule within the tested set displayed MIC < 100 microg/ml.

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The Comparative Study of Equisetum pratense, E. sylvaticum, E. telmateia: Accumulation of Silicon, Antioxidant and Antimicrobial Screening

Revista de Chimie ◽

10.37358/rc.19.7.7372 ◽

2019 ◽

Vol 70 (7) ◽

pp. 2519-2523

Author(s):

Denisa Batir Marin ◽

Oana Cioanca ◽

Mihai Apostu ◽

Cristina Gabriela Tuchilus ◽

Cornelia Mircea ◽

...

Keyword(s):

Antimicrobial Activity ◽

Methanol Extract ◽

Previous Treatment ◽

Total Phenolic ◽

Quantitative Chemical Analysis ◽

Qualitative And Quantitative ◽

Antioxidant And Antimicrobial Activity ◽

The Comparative Study

The objective of the current study is represented by the determination of silica and a phytochemical screening of phenolic derivates of some Equisetum species. The antioxidant and antimicrobial activity for Equisetum pratense Ehrh.,, Equisetum sylvaticum L. and Equisetum telmateia Ehrh. (sin. Equisetum maximum Lam.) were also investigated. The concentration of silicon (Si) in plants was determined by the spectrophotometric method using previous treatment with NaOH 50% both for the stem and the nodal branches [1]. Results obtained varied from 95.12 to 162.10 SiO2 mg/g dry plant which represents 4.44% to 7.58% Si/100g dry sample. Two types of total extracts were obtained using different solvents and were subjected to qualitative and quantitative chemical analysis considering total phenolic content [2]. The highest concentration of investigated compounds was found in the methanolic extract, E. sylvaticum, 196.5mg/g dry sample. Antioxidant activity was monitored spectrophotometrically and expressed in terms of IC50 (�g/mL) [3]. Values gathered ranged from 261.7 to 429.5 �g/mL. The highest capacity to neutralized DPPH radicals was found in E. sylvaticum. In vitro antimicrobial activity was determined using difusimetric method [4]. Testing was performed on four microorganisms: three strains of bacteria and one species of fungi. Different effects were noticed against the bacteria, furthermore the methanol extract appeared to be most efficient. All extracts showed significand antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Candida albicans (ATCC 90028) and weak to no activity against Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922).

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Reduction in the in vitro sensitivity oF Drechslera tritici-repentis, isolated from wheat, to strobilurin and triazole fungicides

Summa Phytopathologica ◽

10.1590/0100-5405/2160 ◽

2017 ◽

Vol 43 (1) ◽

pp. 20-25

Author(s):

Rosane Baldiga Tonin ◽

Erlei Melo Reis ◽

Aveline Avozani

Keyword(s):

Inhibitory Concentration ◽

In Vitro Sensitivity ◽

Randomized Design ◽

Inhibition Data ◽

Ic50 Values ◽

Control Failure ◽

Quinone Outside Inhibitors ◽

Completely Randomized Design

ABSTRACT Reports of failure in the chemical control of wheat yellow leaf spot led to determination of the sensitivity of Drechslera tritici-repentis (Dtr) to the fungicides quinone outside inhibitors (QoIs) and demethylation inhibitors (DMIs). The IC50 was obtained for strobilurins (azoxystrobin, kresoxim-methyl, picoxystrobin and pyraclostrobin) and for triazoles (cyproconazole, epoxiconazole, propiconazole, prothioconazole and tebuconazole), using five Dtr isolates. Seven concentrations of the fungicides were tested in the bioassay: 0.00; 0.01; 0.10; 1.00; 10:00 and 20.00 and 40.00 mg/L active ingredient (a.i.). Assays consisted of completely randomized design and four replicates. Each experiment was performed twice, using the average of the two tests for statistical analysis. The percentage inhibition data for conidial germination (QoIs) and for mycelial growth (DMIs) were subjected to logarithmic regression analysis, calculating the 50% inhibitory concentration (IC50) based on the generated equation. There was a reduction in the sensitivity of Dtr isolates to strobilurins. IC50 values ranged from 0.58 to > 40.00 mg/L. The lowest sensitivity of isolates was detected for azoxystrobin, kresoxim-methyl, picoxystrobin and trifloxystrobin. Pyraclostrobin was most efficient, showing IC50 between 0.58 and 1.03 mg/L. The IC50 ranged from 0.35 to 1.37 mg/L for epoxiconazole, from 0.49 to 1.28 mg/L for propiconazole and from 1.41 to 2.34 mg/L for tebuconazole. Prothioconazole was most potent, showing IC50 between 0.09 and 0.21 mg/L. The hypothesis that the control failure can be attributed to the reduced Dtr sensitivity to the fungicides QoIs and DMIs was confirmed.

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In Vitro Activities of Designed Antimicrobial Peptides against Multidrug-Resistant Cystic Fibrosis Pathogens

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.6.1435 ◽

1999 ◽

Vol 43 (6) ◽

pp. 1435-1440 ◽

Cited By ~ 51

Author(s):

Ute Schwab ◽

Peter Gilligan ◽

Jesse Jaynes ◽

David Henke

Keyword(s):

Cystic Fibrosis ◽

Antimicrobial Peptides ◽

Burkholderia Cepacia ◽

Wide Spectrum ◽

Multidrug Resistant ◽

Medium Composition ◽

Peptide Antibiotics ◽

Rpmi Medium ◽

Multidrug Resistant Pathogens

ABSTRACT The emergence of multidrug-resistant pathogens renders antibiotics ineffective in the treatment of lung infections in patients with cystic fibrosis (CF). Designed antimicrobial peptides (DAPs) are laboratory-synthesized peptide antibiotics that demonstrate a wide spectrum of antibacterial activity. Optimal conditions for susceptibility testing of these peptides have not yet been established. Medium composition is clearly a major factor influencing the results and reproducibilities of susceptibility tests. Using time-kill assays, we tested the effects of different media and buffers on the bactericidal activities of the peptides D2A21 and D4E1 onStaphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853. Each peptide at 1 and 5 μM was incubated with bacteria in the different media and buffers. Both peptides were most active in Tris-HCl buffer against S. aureus andP. aeruginosa. Among the more complex media tested, modified RPMI medium was the medium in which the peptides demonstrated the highest activity, while it supported the growth of the bacteria. The broth microdilution technique was used to test the activities of D2A21 and D4E1 in modified RPMI medium against multidrug-resistant pathogens from patients with CF. The MICs of DAPs for methicillin-resistant S. aureus ranged from 0.25 to 4 μg/ml, those for multidrug-resistant P. aeruginosa ranged from 0.125 to 4 μg/ml, those for Stenotrophomonas maltophilia ranged from 0.5 to 32 μg/ml, and those forBurkholderia cepacia ranged from 32 to ≥64 μg/ml. When the activity of peptide D2A21 was compared with that of the tracheal antimicrobial peptide (TAP), D2A21 had greater potency than TAP againstP. aeruginosa. In addition, no difference in the MICs of D2A21 was seen when it was tested in nutrient broth supplemented with NaCl at different concentrations. Thus, DAPs are a class of salt-insensitive antibiotics potentially useful in the treatment of CF patients harboring multidrug-resistant P. aeruginosa.

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Gatorbulin-1, a distinct cyclodepsipeptide chemotype, targets a seventh tubulin pharmacological site

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2021847118 ◽

2021 ◽

Vol 118 (9) ◽

pp. e2021847118

Author(s):

Susan Matthew ◽

Qi-Yin Chen ◽

Ranjala Ratnayake ◽

Charles S. Fermaintt ◽

Daniel Lucena-Agell ◽

...

Keyword(s):

Total Synthesis ◽

Wide Spectrum ◽

Targeted Chemotherapy ◽

Structural Determination ◽

Marine Cyanobacterium ◽

Microtubule Stabilization ◽

Biochemical Studies ◽

Β Tubulin

Tubulin-targeted chemotherapy has proven to be a successful and wide spectrum strategy against solid and liquid malignancies. Therefore, new ways to modulate this essential protein could lead to new antitumoral pharmacological approaches. Currently known tubulin agents bind to six distinct sites at α/β-tubulin either promoting microtubule stabilization or depolymerization. We have discovered a seventh binding site at the tubulin intradimer interface where a novel microtubule-destabilizing cyclodepsipeptide, termed gatorbulin-1 (GB1), binds. GB1 has a unique chemotype produced by a marine cyanobacterium. We have elucidated this dual, chemical and mechanistic, novelty through multidimensional characterization, starting with bioactivity-guided natural product isolation and multinuclei NMR-based structure determination, revealing the modified pentapeptide with a functionally critical hydroxamate group; and validation by total synthesis. We have investigated the pharmacology using isogenic cancer cell screening, cellular profiling, and complementary phenotypic assays, and unveiled the underlying molecular mechanism by in vitro biochemical studies and high-resolution structural determination of the α/β-tubulin−GB1 complex.

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ANTIMICROBIAL ACTIVITY STUDY OF NEW QUINAZOLIN-4(3H)-ONES AGAINST STAPHYLOCOCCUS AUREUS AND STREPTOCOCCUS PNEUMONIAE

Pharmacy & Pharmacology ◽

10.19163/2307-9266-2021-9-4-318-329 ◽

2021 ◽

Vol 9 (4) ◽

pp. 318-329

Author(s):

M. A. Samotrueva ◽

A. A. Ozerov ◽

A. A. Starikova ◽

N. M. Gabitova ◽

D. V. Merezhkina ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Activity ◽

Streptococcus Pneumoniae ◽

Active Sites ◽

Wide Spectrum ◽

Experimental Studies ◽

Amide Group ◽

Pharmacological Effect ◽

Dilution Method

Quinazolin-4(3H)-one derivatives exhibiting a wide spectrum of a pharmacological activity, represent a promising class of substances used to obtain antibacterial agents, which is especially important in the context of the emergence of pathogenic microorganisms’ resistance to drugs used in medicine. It has been proved that compounds having a naphthyl radical in the molecule, as well as an amide group bound to the benzene ring as quinazolinone substituents, are characterized by a pronounced antimicrobial activity against Staphylococcus aureus and Streptococcus pneumoniae.The aim of the research is a primary microbiological screening of the in vitro antimicrobial activity of new quinazolin-4(3H)-one derivatives against Staphylococcus aureus and Streptococcus pneumoniae, as well as the assessment of the relationship between the pharmacological effect and the structural transformation of the substance molecule, lipophilicity and the possibility of forming resistance to them.Materials and methods. The experimental studies have been carried out using well-known nosocomial pathogens of infectious and inflammatory diseases Staphylococcus aureus and Streptococcus pneumoniae by a serial dilution method.Results. A compound containing a naphthyl radical in its structure, which contributes to an increase in the hydrophobicity of the substance and its solubility in the membrane of a bacterial cell, has a bacteriostatic effect against both Staphylococcus aureus and Streptococcus pneumoniae. A similar pharmacological effect is exhibited by a derivative with an amide group as a substituent of the quinazolinone nucleus linked to a phenyl radical, which probably contributes to an increase in the degree of binding to active sites of enzymes involved in the DNA replication, and protein synthesis. Obviously, the increased lipophilicity, which promotes better binding to the efflux protein, cannot serve as objective characteristics of the emergence possibility of the pathogen’s resistance to this substance.Conclusion. Among the synthesized compounds, the leading substances that exhibit an antimicrobial activity against Staphylococcus aureus and Streptococcus pneumonia, have been identified. The assessment of the chemical structure made it possible to substantiate their pharmacological action and draw conclusions about the possibility of developing resistance to it in microbial cells.

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

Antibiotics ◽

10.3390/antibiotics10111309 ◽

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.

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