Antimicrobial Activities and Biofilm Inhibition Properties of Trigonella foenumgraecum Methanol Extracts against Multidrug-Resistant Staphylococcus aureus and Escherichia coli

Evaluating the efficacy of doripenem against Staphylococcus aureus in vancomycin-resistant strains

Determination of antibiotic susceptibility is a crucial aspect of antimicrobial therapy. The objective of this study was to determine the specific susceptibility of Staphylococcus aureus (SA) to the antibiotic doripenem. A total of 180 clinical isolates from VRSA patients were tested against doripenem using minimum inhibitory concentration (MIC) and disk diffusion tests. The overall findings indicated that doripenem exhibited a high sensitivity level for SA isolates, with an MIC50 of 60 μg/mL and a MIC90 of 0.5 mg/mL. Additionally, the antimicrobial activity of doripenem, both alone and in combination with amoxiclav against VRSA showed consistent biofilm inhibition within 48 and 24 h, respectively. Furthermore, these results demonstrate that doripenem maintains its high efficacy against VRSA and the combination of amoxiclav with doripenem presents a potential option for managing these resistant infections.

Psyllium and okra mucilage as co-carrier wall materials for fenugreek oil encapsulation and its utilization as fat replacers in pan bread and biscuit production

This study aimed to investigate the potential use of okra and psyllium mucilage as co-carrier wall materials with whey protein and gum Arabic polymers for encapsulation of fenugreek oil to mask its undesirable flavor and promote their health benefits. Particle size, zeta potential, encapsulation efficiency, morphological properties and fatty acid profiles of crude and encapsulated oils were examined using zeta-sizer, SEM and GC-MS techniques. Crude and encapsulated fenugreek oils were added as functional ingredients during production of pan bread and biscuits. The quality characteristics (baking quality, color and organoleptic properties) of bread and biscuits as well as microbiological properties of bred samples were evaluated. Results showed that the forming microcapsules had sphere particles with the size of 5.05 and 31.64 μm for okra and pysillium mucilage, respectively and had smooth continuous surfaces with no holes or fractures. Fatty acids analysis showed that fenugreek oil is superior functional edible oil, rich in unsaturated fatty acids. The organoleptic properties of products were improved when fat replaced with encapsulated fenugreek oil with okra or psyllium mucilage. Likewise, encapsulated fenugreek oil showed antimicrobial activity in bread samples during storage period. On contrary, Bread and biscuits incorporated with crude fenugreek oil gained the lowest scores for all organoleptic parameters. Regarding these results, encapsulated fenugreek oil presents good fat alternatives in dough formulations with acceptable technological, sensory and antimicrobial properties. However, further investigations still needed regarding the biological activity of encapsulated fenugreek oil and its utilization as a food supplement in other food products.

Phytochemical Composition, Antioxidant, Antimicrobial, Antibiofilm, and Antiquorum Sensing Potential of Methanol Extract and Essential Oil from Acanthus polystachyus Delile (Acanthaceae)

The evolution of microbes in response to conventional antimicrobials leads to antimicrobial resistance (AMR) and multidrug resistance (MDR), and it is a global threat to public health. Natural products are possible solutions to this massive challenge. In this study, the potential of Acanthus polystachyus extracts was investigated for phytochemical composition and biological properties as antimicrobials. Gas chromatography-mass spectra (GC-MS) analysis of methanol extract (ME) and essential oil (EO) detected 79 and 20 compounds, respectively. The major compounds identified in ME and their abundance were β-sitosterol acetate (16.06%), cholest-5-en-3-yl (9Z)-9-octadecenoate (9.54%), 1-dodecanol (7.57%), (S)-(E)-(-)-4-acetoxy-1-phenyl-2-dodecen-1-one (6.03%), neophytadiene (5.7%), (E)-2-nonadecene (3.9%), hexanol-4-D2 (2.92%), and decane (2.4%). Most compounds have known bioactive functions. In EO, the major compounds were stearyl alcohol (25.38%); cis-9-tetradecenoic acid, isobutyl ester (22.95%); butyl 9-tetradecenoate (10.62%); 11,13-dimethyl-12-tetradecen-1-ol acetate (10.14%); ginsenol (3.48%); and diisooctyl phthalate (2.54%). All compounds are known to be bioactive. The antioxidant activity of ME and EO ranged from 48.3 to 84.2% radical scavenging activity (RSA) and 45.6 to 82% RSA, respectively, with dose dependency. The disc diffusion assay for the antimicrobial activity of ME revealed high inhibition against Acenetobacter baumannii (130.2%), Pseudomonas aeruginosa (100.3%), and Staphylococcus aureus (87.7%). The MIC, MBC/MFC, and MBIC values for ME were 0.5-1.0, 2-4, and 0.5-1.0 mg/mL and for EO were 0.31-0.62, 1.25-2.5, and 0.31-0.62 μL/mL, respectively, indicating inhibition potential as well as inhibition of biofilm formation. The tolerance test values indicated bactericidal activity against most strains and bacteriostatic/fungistatic activity against A. baumannii, E. faecalis, and C. albicans. The antiquorum sensing activity of ME achieved by pyocyanin inhibition assay on P. aeruginosa showed a 51.6% inhibition at 500 μg/mL. These results suggest that ME and EO derived from A. polystachyus leaves are potent, valuable, cost-effective antioxidants and antimicrobials. Both extracts may effectively combat pathogenic and resistant microbes.

Evolving biofilm inhibition and eradication in clinical settings through plant-based antibiofilm agents

BACKGROUND

After almost 100 years since evidence of biofilm mode of growth and decades of intensive investigation about their formation, regulatory pathways and mechanisms of antimicrobial tolerance, nowadays there are still no therapeutic solutions to eradicate bacterial biofilms and their biomedical related issues.

PURPOSE

This review intends to provide a comprehensive summary of the recent and most relevant published studies on plant-based products, or their isolated compounds with antibiofilm activity mechanisms of action or identified molecular targets against bacterial biofilms. The objective is to offer a new perspective of most recent data for clinical researchers aiming to prevent or eliminate biofilm-associated infections caused by bacterial pathogens.

METHODS

The search was performed considering original research articles published on PubMed, Web of Science and Scopus from 2015 to April 2023, using keywords such as "antibiofilm", "antivirulence", "phytochemicals" and "plant extracts".

RESULTS

Over 180 articles were considered for this review with a focus on the priority human pathogens listed by World Health Organization, including Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Inhibition and detachment or dismantling of biofilms formed by these pathogens were found using plant-based extract/products or derivative compounds. Although combination of plant-based products and antibiotics were recorded and discussed, this topic is currently poorly explored and only for a reduced number of bacterial species.

CONCLUSIONS

This review clearly demonstrates that plant-based products or derivative compounds may be a promising therapeutic strategy to eliminate bacterial biofilms and their associated infections. After thoroughly reviewing the vast amount of research carried out over years, it was concluded that plant-based products are mostly able to prevent biofilm formation through inhibition of quorum sensing signals, but also to disrupt mature biofilms developed by multidrug resistant bacteria targeting the biofilm extracellular polymeric substance. Flavonoids and phenolic compounds seemed the most effective against bacterial biofilms.