The New Antibacterial Properties of the Plants: Quo vadis Studies of Anti-virulence Phytochemicals?

The recent increase in bacterial resistance to antibiotics has motivated the resurgence of the study of natural antimicrobial products. For centuries, plants have been recognized for their bactericidal properties. However, in the last two decades, it has been reported that several plant derived metabolites at growth subinhibitory concentrations also tend to have anti-virulence properties, since they reduce the expression of factors that cause damage and the establishment of pathogenic bacteria. In this area of study, plants have been positioned as one of the main natural sources of anti-virulence molecules, but only a small portion of the plant species that exist have been investigated. Also, anti-virulence studies have been primarily focused on analyzing the ability of extracts and compounds to inhibit quorum sensing and biofilms formation in vitro. This mini-review discusses the current panorama, the trends in the study of anti-virulence phytochemicals, as well as their potential for the development of antibacterial therapies.

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Preparation and Characterization of Aminoglycoside-Loaded Chitosan/Tripolyphosphate/Alginate Microspheres against E. coli

Polymers ◽

10.3390/polym13193326 ◽

2021 ◽

Vol 13 (19) ◽

pp. 3326

Author(s):

Estefanía Tiburcio ◽

Eduardo García-Junceda ◽

Leoncio Garrido ◽

Alfonso Fernández-Mayoralas ◽

Julia Revuelta ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Diffusion Mechanism ◽

In Vitro Release ◽

Antibacterial Properties ◽

Fickian Diffusion ◽

Burst Release ◽

E Coli ◽

Gel Beads

Although aminoglycosides are one of the common classes of antibiotics that have been widely used for treating infections caused by pathogenic bacteria, the evolution of bacterial resistance mechanisms and their inherent toxicity have diminished their applicability. Biocompatible carrier systems can help sustain and control the delivery of antibacterial compounds while reducing the chances of antibacterial resistance or accumulation in unwanted tissues. In this study, novel chitosan gel beads were synthesized by a double ionic co-crosslinking mechanism. Tripolyphosphate and alginate, a polysaccharide obtained from marine brown algae, were employed as ionic cross-linkers to prepare the chitosan-based networks of gel beads. The in vitro release of streptomycin and kanamycin A was bimodal; an initial burst release was observed followed by a diffusion mediated sustained release, based on a Fickian diffusion mechanism. Finally, in terms of antibacterial properties, the particles resulted in growth inhibition of Gram-negative (E. coli) bacteria.

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An In Vitro Coumarin-Antibiotic Combination Treatment of Pseudomonas aeruginosa Biofilms

Natural Product Communications ◽

10.1177/1934578x20987744 ◽

2021 ◽

Vol 16 (1) ◽

pp. 1934578X2098774

Author(s):

Jinpeng Zou ◽

Yang Liu ◽

Ruiwei Guo ◽

Yu Tang ◽

Zhengrong Shi ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Drug Resistance ◽

Combination Treatment ◽

Crude Extract ◽

Biofilm Formation ◽

Bacterial Resistance ◽

Antibacterial Properties ◽

Biofilm Growth ◽

Antibiotic Combination

The drug resistance of Pseudomonas aeruginosa is a worldwide problem due to its great threat to human health. A crude extract of Angelica dahurica has been proved to have antibacterial properties, which suggested that it may be able to inhibit the biofilm formation of P. aeruginosa; initial exploration had shown that the crude extract could inhibit the growth of P. aeruginosa effectively. After the adaptive dose of coumarin was confirmed to be a potential treatment for the bacteria’s drug resistance, “coumarin-antibiotic combination treatments” (3 coumarins—simple coumarin, imperatorin, and isoimperatorin—combined with 2 antibiotics—ampicillin and ceftazidime) were examined to determine their capability to inhibit P. aeruginosa. The final results showed that (1) coumarin with either ampicillin or ceftazidime significantly inhibited the biofilm formation of P. aeruginosa; (2) coumarin could directly destroy mature biofilms; and (3) the combination treatment can synergistically enhance the inhibition of biofilm formation, which could significantly reduce the usage of antibiotics and bacterial resistance. To sum up, a coumarin-antibiotic combination treatment may be a potential way to inhibit the biofilm growth of P. aeruginosa and provides a reference for antibiotic resistance treatment.

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The characteristics of lactic acid bacteria isolated from fermented food as potential probiotics

Journal of Basic and Clinical Physiology and Pharmacology ◽

10.1515/jbcpp-2020-0482 ◽

2021 ◽

Vol 32 (4) ◽

pp. 743-749

Author(s):

Victoria Yulita Fitriani ◽

Budi Suprapti ◽

Muhammad Amin

Keyword(s):

Lactobacillus Acidophilus ◽

Bile Salts ◽

Pathogenic Bacteria ◽

Fruit Juice ◽

Lactobacillus Reuteri ◽

Antibacterial Properties ◽

Fermented Food ◽

Cow’S Milk ◽

Cow's Milk

Abstract Objectives This study aims to determine the characteristics of Lactobacillus acidophilus and Lactobacillus reuteri from fermented soursop fruit juice and cow’s milk, respectively as probiotic candidate based on exposure to pH, bile salts, pathogenic bacteria, and antibiotics. Methods In vitro studies were conducted to examine the resistance of Lactobacillus acidophilus and Lactobacillus reuteri in pH 2, 2.5, 3.2, and 7.2, resistance to bile salts, resistance to pathogenic bacteria (Escherichia coli, Staphylococcus aureus and Enterococcus faecalis) and antituberculosis antibiotics. Results Viability of Lactobacillus acidophilus and Lactobacillus reuteri isolates remained unchanged (6.3 × 107 CFU/mL and 5.03 × 107 CFU/mL) at various acidic pH, and had a low survival rate in Ox gall 0.3% (bile salts). These isolates also showed antibacterial properties against pathogens in the gastrointestinal tract. Both of these bacteria are quite safe to be used together with ofloxacin, linezolid, moxifloxacin, and levofloxacin, antibiotic for tuberculosis therapy. Conclusions The results showed that Lactobacillus acidophilus and Lactobacillus reuteri from fermented soursop fruit juice and cow’s milk respectively fulfilled the characteristics of probiotic and could potentially be used as adjunct therapy in tuberculosis drug-resistance.

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Application of Magnetic Nanoparticles with Structure of Core-shell, as Bactericidal

Immunology and Inflammation Diseases Therapy ◽

10.31579/2637-8876/023 ◽

2018 ◽

Vol 2 (1) ◽

pp. 01-04

Author(s):

Mansour Binandeh

Keyword(s):

Magnetic Nanoparticles ◽

Pathogenic Bacteria ◽

Antibacterial Properties ◽

Correlation Method ◽

Core Shell ◽

Ft Ir ◽

Chemical Correlation ◽

Ir Analysis ◽

The Magnetic Field

Initially, magnetic nanoparticles (MNP) Fe3O4 are synthesized by a chemical correlation method and its core / shell structure is detected using SEM, FT-IR analysis. The purpose of this production was to use the nanoparticle performance level in the absorption of antibiotics, namely, ampicillin (amp). Absorption sampling was analyzed by UV-Vis spectrophotometer and the results indicate that the absorbance of the ampere increases to 85%. The bond between these two is electrostatic bonding, which was confirmed by EDX analysis. Ultimately, this compound was used for the antibacterial process. In this case, the MNP-amp compound was added in a natural amount of 20 μl a bacterial culture pattern overnight (In-vitro). The results showed that 95% of the bacteria were killed (confirmation of antibacterial properties of MNP). Therefore, it can be transmitted intentionally by controlling the magnetic field into living cells for the destruction of pathogenic bacteria.

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Antibacterial properties of rain tree ( ) and Mexican sunflower (Tithonia diversifolia ) used as fodder in ruminant nutrition

Nigerian Journal of Animal Production ◽

10.51791/njap.v45i2.528 ◽

2020 ◽

Vol 45 (2) ◽

pp. 331-341

Author(s):

F. T. Ajayi ◽

S. O. Omotoso ◽

O. J. Babayemi

Keyword(s):

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Antibacterial Properties ◽

Tithonia Diversifolia ◽

Standard Procedures ◽

Fodder Plants ◽

Zones Of Inhibition ◽

Ethanol Extracts ◽

Albizia Saman

Acetone and ethanol extracts of Albizia saman (ASL) and Tithonia diversifolia (TDL) leaves used as fodder for ruminant were evaluated for their antibacterial properties against selected pathogenic bacteria. Phytochemical screening was determined according to standard procedures, while antibacterial activity was by agar well diffusion and broth micro dilution methods. The levels of tannin (0.29 and 0.34 mg/100g); saponin (0.75 and 0.59 mg/100g); oxalates (0.17 and 0.14mg/100g); and phytate (0.11 and 0.12 mg/100g) in the fodder plants were below critical levels that may affect digestibility in ruminants. Acetone and ethanol extracts from ASL and TDL showed maximum zones of inhibition against Staphylococcus aureus (19.00 and 14.50 mm; 23.00 and 21.50 mm) and Pseudomonas aeruginosa (15.50 and 12.00 mm; 18.50 and 17.00 mm), respectively compared to Gentamycin (9.97 mm). Minimum inhibitory concentration (MIC) values of acetone and ethanol extracts from ASL ranged from 0.10 to 0.28 mg/mL and 0.13 to 0.22 mg/mL, while TDL extracts ranged from 0.20 to 0.32 mg/mL and 0.20 to 0.31 mg/mL, respectively for all the tested organisms. Minimum bactericidal concentration (MBC) values of ethanol extracts from both plant ranged from 0.5-0.80 mg/mL and 0.7-0.90 mg/mL compared to MBC values (0.02-0.04 mg/mL) of the reference antibiotic (gentamycin) for all the tested bacteria species. In conclusion, antibacterial properties exhibited by the plant extract implied that the bioactive compounds are potential antibacterial agents against pathogenic bacteria of ruminant or foodborne pathogens in vitro.

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The Application of a Recombinant Antimicrobial Peptide of Thrombocidin-1 expressed in Pichia pastoris as a Novel Approach Against Some Oral Pathogenic Bacteria: An In-vitro Study

Protein and Peptide Letters ◽

10.2174/0929866528666211126161928 ◽

2021 ◽

Vol 28 ◽

Author(s):

Fatemeh Forouzanfar ◽

Hamideh Sadat Mohammadipour ◽

Majid Akbari ◽

Reza Beyraghshamshir ◽

Abbas Tanhaeian ◽

...

Keyword(s):

Pichia Pastoris ◽

Pathogenic Bacteria ◽

Antibacterial Properties ◽

Dilution Method ◽

Human Gingival Fibroblast ◽

Gingival Fibroblast ◽

Fibroblast Cells ◽

Oral Infections ◽

Oral Pathogens

Objective: Oral infections and dental caries are considered serious health problems. Therefore, searching for new agents with antimicrobial properties seems to be crucial. This study aimed to evaluate the antimicrobial activity of the recombinant Thrombocidin-1 [TC-1] peptide on some oral pathogens. Also, the cytotoxicity of this peptide on human gingival fibroblast cells was investigated. Methods & Materials: In this study, Pichia pastoris was used for the expression of recombinant TC-1. The microbroth dilution method was used to determine the minimum inhibitory concentration [MIC] and minimum bacterial concentration [MBC]. It tested against four main oral pathogens; Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis, and Enterococcus faecalis. Moreover, the cytotoxicity analysis was done on gingival fibroblast cells by the MTT method. The data were analyzed using a two-way analysis of variance [ANOVA] and Tukey’s HSD tests. Results: The most bactericidal effect of TC-1 was against S. salivarius, the highest bacteriostatic effect was against S. salivarius, and S. oralis had the lowest MIC value of 1.512 μg/ml. The Thrombocidin-1 peptide showed lower antibacterial properties against E. faecalis compared with CHX, unlike the stronger antimicrobial effect on examined streptococci. According to cytotoxicity examination, no concentration of TC-1 presented over 50% growth inhibition [IC50] of the fibroblasts cells. Conclusion: Based on antimicrobial tests and cytotoxicity results, the Thrombocidin-1 peptide may be useful as a safe antibacterial agent against some oral pathogens in dental materials.

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Essential Oils of Aromatic Plants with Antibacterial, Anti-Biofilm and Anti-Quorum Sensing Activities against Pathogenic Bacteria

Antibiotics ◽

10.3390/antibiotics9040147 ◽

2020 ◽

Vol 9 (4) ◽

pp. 147 ◽

Cited By ~ 5

Author(s):

Marlon Cáceres ◽

William Hidalgo ◽

Elena Stashenko ◽

Rodrigo Torres ◽

Claudia Ortiz

Keyword(s):

Escherichia Coli ◽

Antimicrobial Activity ◽

Quorum Sensing ◽

Essential Oils ◽

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Thymus Vulgaris ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Biofilm Inhibition

Both the ability of bacteria to form biofilms and communicate through quorum sensing allows them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, seventeen essential oils (EOs) were investigated for the antimicrobial, antibiofilm, and anti-quorum sensing activities on Escherichia. coli O157:H7, Escherichia coli O33, and Staphylococcus epidermidis ATCC 12228. All essential oils were isolated from plant material by using hydrodistillation and analyzed by GC-MS. The antimicrobial activity was performed by using the microdilution technique. Subinhibitory concentrations of each EO were assayed for biofilm inhibition in both bacterial strains. Quantification of violacein in Chromobacterium violaceum CV026 was performed for the anti-quorum sensing activity. The cytotoxicity activity of the EOs was evaluated on Vero cell line by using MTT method. Thymol-carvacrol-chemotype (I and II) oils from Lippia origanoides and Thymus vulgaris oil exhibited the higher antimicrobial activity with MIC values of 0.37–0.75 mg/mL. In addition, these EOs strongly inhibited the biofilm formation and violacein (QS) production in a concentration-dependent manner, highlighting thymol-carvacrol-chemotype (II) oil as the best candidate for further studies in antibiotic design and development against bacterial resistance.

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Evaluation and Comparison of Antibacterial Efficacy of Herbal Extracts in Combination with Antibiotics on Periodontal pathobionts: An in vitro Microbiological Study

Antibiotics ◽

10.3390/antibiotics8030089 ◽

2019 ◽

Vol 8 (3) ◽

pp. 89 ◽

Cited By ~ 9

Author(s):

Shahabe Abullais Saquib ◽

Nabeeh Abdullah AlQahtani ◽

Irfan Ahmad ◽

Mohammed Abdul Kader ◽

Sami Saeed Al Shahrani ◽

...

Keyword(s):

Antibacterial Activity ◽

Plant Extracts ◽

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Antimicrobial Agents ◽

Synergistic Activity ◽

Antibacterial Efficacy ◽

Herbal Extracts ◽

Inhibition Zones

Background: In the past few decades focus of research has been toward herbal medicines because of growing bacterial resistance and side effects of antimicrobial agents. The extract derived from the plants may increase the efficacy of antibiotics when used in combination against pathogenic bacteria. In the current study, the synergistic antibacterial efficacy of plant extracts in combination with antibiotics has been assessed on selected periodontal pathogens. Methods: Ethanolic extracts were prepared from Salvadora persica (Miswak) and Cinnamomum zeylanicum (Ceylon cinnamon), by the soxhalate method. Plaque samples were collected from clinical periodontitis patients to isolate and grow the periodontal pathobionts under favorable conditions. Susceptibility of bacteria to the extracts was assessed by gauging the diameter of the inhibition zones. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant extracts were determined against each bacterium. Synergistic activity of plants extract in combination with antibiotics against the bacteria was also assessed by measuring the diameter of the inhibition zones. Results: Ethanolic extract of both the plants showed an inhibitory effect on the proliferation and growth of all four strains of periodontal pathobionts. Maximum antibacterial activity was exhibited by C. zeylanicum against Tannerella forsythia (MIC = 1.56 ± 0.24 mg/mL, MBC = 6.25 ± 0.68 mg/mL), whereas among all the studied groups the minimum activity was reported by C. zeylanicum against Aggregatibacter actinomycetemcomitans the (MIC = 12.5 ± 3.25 mg/mL, MBC = 75 ± 8.23 mg/mL). Combination of herbal extracts with different antibiotics revealed a synergistic antibacterial effect. The best synergism was exhibited by S. persica with metronidazole against A. actinomycetemcomitans (27 ± 1.78). Conclusions: Current in vitro study showed variable antibacterial activity by experimented herbal extracts against periodontal pathobionts. The synergistic test showed significant antibacterial activity when plant extracts were combined with antibiotics.

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Novel bacteria degrading N-acylhomoserine lactones and their use as quenchers of quorum-sensing-regulated functions of plant-pathogenic bacteria

Microbiology ◽

10.1099/mic.0.26375-0 ◽

2003 ◽

Vol 149 (8) ◽

pp. 1981-1989 ◽

Cited By ~ 164

Author(s):

Stéphane Uroz ◽

Cathy D'Angelo-Picard ◽

Aurélien Carlier ◽

Miena Elasri ◽

Carine Sicot ◽

...

Keyword(s):

Quorum Sensing ◽

Pathogenic Bacteria ◽

Rhodococcus Erythropolis ◽

Homoserine Lactone ◽

Signal Molecules ◽

In Planta ◽

Signal Molecule ◽

Violacein Production ◽

Regulated Functions

Bacteria degrading the quorum-sensing (QS) signal molecule N-hexanoylhomoserine lactone were isolated from a tobacco rhizosphere. Twenty-five isolates degrading this homoserine lactone fell into six groups according to their genomic REP-PCR and rrs PCR-RFLP profiles. Representative strains from each group were identified as members of the genera Pseudomonas, Comamonas, Variovorax and Rhodococcus. All these isolates degraded N-acylhomoserine lactones other than the hexanoic acid derivative, albeit with different specificity and kinetics. One of these isolates, Rhodococcus erythropolis strain W2, was used to quench QS-regulated functions of other microbes. In vitro, W2 strongly interfered with violacein production by Chromobacterium violaceum, and transfer of pathogenicity in Agrobacterium tumefaciens. In planta, R. erythropolis W2 markedly reduced the pathogenicity of Pectobacterium carotovorum subsp. carotovorum in potato tubers. These series of results reveal the diversity of the QS-interfering bacteria in the rhizosphere and demonstrate the validity of targeting QS signal molecules to control pathogens with natural bacterial isolates.

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Enhancement of the ability of the porcine colonic microflora to resist colonisation by Salmonella poona, in an in vitro intestinal simulation

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200007365 ◽

2002 ◽

Vol 2002 ◽

pp. 80-80

Author(s):

K. Hillman

Keyword(s):

Quorum Sensing ◽

Culture Filtrate ◽

Pathogenic Bacteria ◽

Intestinal Microflora ◽

Antagonistic Activity ◽

Simulation System ◽

Current Experiment ◽

Subsequent Work ◽

Colonic Microflora

The ability of the porcine intestinal microflora to resist the establishment of pathogenic bacteria has been demonstrated previously (Hillman et al, 1994). Subsequent work has shown that certain intestinal lactobacilli react to the presence of a culture filtrate derived from a coliform pathogen by increasing their antagonistic activity towards that pathogen (Hillman and Robertson, unpublished), indicating the presence of a quorum-sensing or related mechanism. The current experiment was devised to determine whether a similar effect could be produced within the entire porcine colonic microflora, using an in vitro simulation system.

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