Minimum Bactericidal Concentration Research Articles

Evaluation of phytochemical, in vitro antibacterial and rate of kill assay of <i>Terminalia avicennioides</i> leaf against some bacteria associated with diarrhoea

The study was aimed to evaluate the phytochemical constituents, in vitro antibacterial and rate of kill assay of Terminalia avicennioides leaf extract against some bacteria associated with diarrhoea. The phytochemical constituents of the ethanol of Terminalia avicennioides leaf, aqueous, n- butanol, and ethyl acetate fractions of the leaf extract were determined using standard analytical methods. The antibacterial activities of the leaf extract and extract fractions against clinical isolates of Salmonella Typhimurium and Escherichia coli isolated from diarrhoeaic patients were determined in vitro by agar diffusion, dilution and time - kill methods. The result of phytochemical screening revealed the presence of carbohydrates, cardiac glycosides, saponins, flavonoides, tannins, alkaloids, phenols and triterpenes. The crude extract and extract fractions of T. avicennioides leaf were effective against the test bacterial isolates at varied concentration of extracts but the n-butanol fraction was more effective with Minimum inhibitory and Minimum Bactericidal Concentration of 6.25 and 12.5mg/ml. The clinical isolates of E. coli and S. Typhimurium were completely killed within 180 minutes of exposure to ethanol leaf extract and extract fractions at varied MBCs of 12.5 mg/ml and 25.0 mg/ml. The clinical isolates of E. coli and S. Typhimurium were more susceptible to n-butanol fraction within 120 minutes of exposure to the extract fraction.

Niosome gels encapsulate green mangosteen peel extract (Garcinia mangostana L.) as an anti-acne-inducing bacterial and anti-inflammatory activity

This research aims to develop a niosome gel from green mangosteen peel extract (Garcinia mangostana L.) by maceration with an ethanol solvent. The result of the yield percentage was 14.35 ± 0.90. The result of analyzing the phytochemicals by high-performance liquid chromatography (HPLC) was that tannin and xanthone were equal to 0.7483 ± 0.0825 mg per 100 mg of extract and 0.02964 ± 0.0088 mg per 100 mg of extract, respectively. The results of the determination of the effect include anti-inflammatory and anti-bacterial (Cutibacterium acnes) as anti-inflammatory with nitric oxide from LPS-induced macrophage cells up to a maximum equal to 29.10 ± 4.78% as a concentration at 1 mg mL–1 as acetonide can inhibit nitric oxide equal to 33.12 ± 3.62% as a concentration at 1 mg mL–1. and anti-bacterial (Cutibacterium acnes) by broth microdilution and drop plate methods, it was found that clindamycin has a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 0.08 μg mL–1 and 0.31 μg mL–1, respectively. The development of niosomes consisting of cholesterol, tween 60, and mangosteen peel extract at 1% w w–1 and 2% w w–1 in every formula showed good stability. The reduction of particle size in the formula by an ultrasonic bath at 30 minutes and measurement of particle size with a transmission electron microscope (TEM) were found to be equal to 1,265 and 123 – 219 nm, respectively. The polydispersity index (PDI) was in the range of 0.1 – 0.2, and the zeta potential value was in the range of –26.15 to –28.61 mV. The result of hydration and trans epidermal water loss (TEWL) was found to be that after 4 weeks of use, the formula containing the niosomes of mangosteen peel extract concentrated at 2% w w–1 maximizes skin moisture. It has a value of 346 ± 39.27 and has the least surface water loss. GRAPHICAL ABSTRACT HIGHLIGHTS The green mangosteen peel extract (Garcinia mangostana L.) can inhibiting nitric oxide production from LPS-induced macrophage cells up to 29.10 ± 4.78% at a concentration of 1 mg ml-1, the lowest inhibitory (MIC) and kill (MBC) concentration of C. acnes bacteria less than 0.24 mg ml-1. The particle size of niosomes encapsulate extracts before reducing particle size equal to 1,265 nm. and after reducing particle size in the range of 123 - 219 nm. The skin hydration value after using product for 4 weeks as niosome gel encapsulate extract 2%w w-1 of extract was maximum moisture and minimal water loss.

Bio-functional properties and phytochemical composition of selected Apis mellifera honey from Africa

Globally, the demand for natural remedies such as honey to manage ailments has increased. Yet, the health benefits and chemical composition of African honeys are not well understood. Therefore, this study aimed to characterise the bio-functional properties and the phytochemical composition of 18 Apis mellifera honeys from Kenya, Uganda, and Cameroon in comparison to the popular and commercially available Manuka 5+ honey from New Zealand. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH-RSA) was used to determine the antioxidant property, whilst the agar well diffusion and broth dilution (Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) assays were used to determine antimicrobial property. Further, colorimetric methods were used for phytochemical analysis. Our results showed that honeys collected from Rift Valley region of Kenya (e.g. Poi, Salabani and Mbechot) and Western region of Cameron (e.g. Bangoulap) had the highest antioxidant (DPPH RSA of 41.52–43.81%) and antimicrobial (MIC (3.125–6.25% w/v) and MBC (6.25–12.5% w/v)) activities. Additionally, the total flavonoid (770–970 mg QE/100 g), phenol (944.79–1047.53 mg GAE/100 g), terpenoid (239.78–320.89 mg LE/100 g) and alkaloid (119.40–266.57 mg CE/100 g) contents reached the highest levels in these bioactive African honeys, which significantly and positively correlated with their bio-functional properties. The functional and phytochemical composition of these bioactive African honeys were similar to or higher than those of the Manuka 5+ honey. Furthermore, gas chromatography-mass spectrometry analysis of African honeys revealed 10 most prominent volatile organic compounds that contribute to their geographical distinction: triacontane, heptacosane, (Z)-9-tricosene, tetracosane, 6-propyl-2,3-dihydropyran-2,4-dione, octacosane, 1,2,4-trimethylcyclohexane, 1,3-bis(1,1-dimethylethyl) benzene, 2-methylheptane and phytol. Overall, our findings suggest that some of the tested African honeys are natural sources of antimicrobial and antioxidant therapies that can be exploited upon further research and commercialized as high value honey.

Synthesis, characterization, antibacterial efficacy, and Cytotoxicity of monoclinic KMg3(Al0.5B0.5)Si3O10F2: A novel material for anticariogenic applications

Fluorophlogopite is a well-known fluorosilicate glass-ceramic derivative known for its bioactivity, machinability and optimal mechanical properties. There is limited information regarding its antibacterial and biocompatible properties. This research paper presents the synthesis and characterization of a novel Boron-doped Fluorphlogopite [KMg3(Al0.5B0.5)Si3O10F2] aiming to improve its antibacterial properties intended for anticariogenic applications. The combustion synthesis method was employed, with oxalyl dihydrazide (ODH) (C2H6N4O2) serving as the fuel. X-ray Diffraction (XRD) analyses unveiled a monoclinic crystal system, showcasing a P21 space group, and an average crystallite size of approximately 28 nm. Morphological scrutiny divulged clustered, irregularly shaped, cluster-like structures. The energy gap was determined to be around 4.97 ± 0.0062 eV. Fourier-Transform Infrared (FTIR) spectroscopy depicted the presence of characteristic bonds. BET analysis indicated the presence of a large surface area and porous structure (mesopores), which may contribute to lower MIC and MBC values, enhancing antibacterial effectiveness. The antibacterial activity, evaluated via agar well diffusion, yielded an 8 mm zone of inhibition. Furthermore, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against S mutans were determined to be 2 mg/ml and 16 mg/ml, respectively. The biocompatibility of the synthesized KMg3(Al0.5B0.5)Si3O10F2 was assessed through the MTT assay, indicating non-toxic behavior at a concentration of 12 μg/ml with 98 % cell viability, while showing moderate toxicity with 61 % viable cells at its highest concentration of 200 μg/ml.

Mycofabrication of bimetal oxide nanoparticles (CuO/TiO2) using the endophytic fungus Trichoderma virens: Material properties and microbiocidal effects against bacterial pathogens

Bimetallic oxide nanoparticles (NPs) have gained the interest of researchers owing to the synergistic mechanism of action by the elements present. Mycosynthesis of nanostructures is a promising, facile, and an environmentally friendly approach. In the present study, CuO/TiO2 NPs were produced using the cell-free filtrate of the endophytic fungus Trichoderma virens. The reaction of the fungal filtrate with the two metal salts, CuSO4.5H2O and TiO2, resulted in the mycosynthesis of the CuO/TiO2 NPs. The prepared bimetal oxide NPs were characterized using XRD, FTIR spectroscopy, EDX, DLS, zeta potential analysis, XPS, Raman scattering, FESEM, and HRTEM. The mycosynthesized CuO/TiO2 NPs exhibited diffraction peaks characteristic of the monoclinic CuO and tetragonal rutile TiO2 crystal planes. Homogeneity and stability were observed as a result of the biological moieties present in the fungal filtrate, which capped the CuO/TiO2 NPs. The prepared CuO/TiO2 NPs were distributed as flake/plate-like and quasi-spherical/nanorod CuO and TiO2 NPs, respectively. A broad-spectrum antibacterial effect was recorded, with zones of inhibition as follows: foodborne pathogens Escherichia coli (14.34 mm), Salmonella enterica serovar Typhimurium (11.32 mm), and Staphylococcus aureus (9.63 mm); and phytopathogenic bacteria involving Clavibacter michiganensis subsp. michiganensis (Cmm, 12.16 mm), C. michiganensis subsp. capsici (Cmc, 11.26 mm), wild type and streptomycin-resistant Pectobacterium carotovorum subsp. carotovorum (Pcc, 11.06 and 12.37 mm, respectively), and wild type and streptomycin-resistant Xanthomonas citri pv citri (Xcc, 12.48 and 12.69 mm, respectively). The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the CuO/TiO2 NPs were determined using the broth microdilution assay. NP-treated bacterial cells at sub-MICs had rough surfaces with membrane defects and exhibited shrinkage, reduction of cell edges, cracks, and fractures on their surfaces. This study provides insights into the potential of the mycosynthesized CuO/TiO2 NPs as alternative nano-antimicrobial agents, which could be employed for future biomedical, agricultural, and pharmaceutical applications.

Comparative antioxidant, antibacterial, and antidiabetic activities of in vitro-grown callus and wild-grown various parts of Piper longum L

BackgroundPiper longum L. is a tropical and subtropical medicinal plant that has been used as antidiabetic, diarrhea, stomachache, cough, asthma, and bronchitis since ancient times. The in vitro-grown callus from the leaf, however, has not been tested and utilized for any of these conditions. Thus, this research pursues to assess the comparative study of antioxidant, antibacterial, and antidiabetic activities of in vitro-grown callus and various parts of Piper longum-grown in the wild. MethodsThe antioxidant activity of crude extracts and the fractions were determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical scavenging assay, the antibacterial activity by agar-well diffusion method, and antidiabetic activity by α-amylase and α-glucosidase inhibition assay. In addition, the total phenol content (TPC) and total flavonoid contents (TFC) were calculated using Folin-Ciocalteau reagent and aluminum chloride complex-forming assay respectively. ResultsThe highest antioxidant activity (IC50=134.81±1.16 µg/mL), TPC (41.22±0.50 mg of GAE/g dry weight), and TFC (73.41±0.53 mg of QE/g dry weight) were obtained in the dichloromethane (DCM) fraction of root than other crude extracts and fractions. The DCM fractions of root exhibited the minimum inhibitory concentration (MIC) at 5.0 mg/mL and minimum bactericidal concentration (MBC) of 8.35 mg/mL to the Staphylococcus aureus. Moreover, the DCM fraction of root showed the highest α-amylase and α-glucosidase inhibition (IC50=365.21±31.02 and 489.07±27.96 µg/mL) than other crude extracts and fractions. To the best of our information, comparative antioxidant (IC50=206.61±0.64 µg/mL), antibacterial (suppressed 80 % of tested bacteria), and antidiabetic (IC50=1165.15±15.63 and 1304.76±12.43 µg/mL) properties of the in vitro-grown callus were recorded for the first time in P. longum, and were found to be comparative to those of the wild-grown parts. ConclusionsThese results showed that wild-grown P. longum roots, particularly the DCM fraction, could be an important source of natural antioxidants, antimicrobials, and antidiabetics for better curative uses than other wild-grown parts and in vitro-grown callus. In vitro-grown callus, however, could be used as a natural drug source and used to conserve P. longum in its natural habitats in the future.

Antimicrobial and antibiofilm activities of Aleppo pine essential oil and enzymes against Salmonella enterica biofilms formed on stainless steel and plastic surfaces

Several foodborne illness outbreaks caused by Salmonella enterica have been associated with the presence of biofilms, particularly on food contact surfaces. The objectives of the current study were: i) to assess the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of Aleppo pine essential oil (APEO) against 5 S. enterica serotypes and their mixture in Tryptone Soy broth at 37 °C and, ii) investigate the antibiofilm activity of two mixtures of 3 hydrolytic enzymes (5% protease, 2.5% α-amylase, and 0.5% lipase or 10% protease, 5% α-amylase, and 1% lipase at 50 °C for 30 min, and APEO at 1, 2 and 4 MIC at 25 °C for 10, 20 or 30 min) as well as sequential use of enzyme mixtures and APEO against S. enterica on stainless steel and plastic surfaces. The results showed that the MIC and MBC values of APEO against S. enterica strains and their mixture were 250–500 μg/ml and 1000-4000 μg/ml, respectively. In general, the antibiofilm activity of enzymes and APEO increased as the concentration increased and exposure time was extended. The results showed that a 1.8 log CFU/coupon reduction (p < 0.05) was obtained using 4 MIC APEO for 30 min at 25 °C. The enzyme-based mixture containing 10% protease, 5% amylase and 1% lipase at 50 °C for 30 min reduced the microbial load of S. enterica in biofilms on stainless steel and plastic surfaces by 2.1 log CFU/coupon (p < 0.05). However, a sequential two-step treatment based on a mixture of 10% protease, 5% α-amylase, and 1% lipase for 30 min at 45 °C followed by 4 MIC APEO for 30 min at room temperature reduced the S. enterica cells in biofilms on stainless steel by 4.6 log CFU/coupon (p < 0.05). These results indicated that enzyme-APEO treatments may be applied as a natural alternative to overcome biofilm formation by S. enterica in the food industry.

Antimicrobial activity and mechanism of chitosan-coated epsilon-poly-lysine nanoliposomes against Alicyclobacillus spp. in apple juice

Epsilon-poly-lysine (EPL), a natural cationic antimicrobial peptide, is widely used in food processing and preservation. However, when applied to fruit and vegetable juice, EPL can cause turbidity and precipitation, which reduces the antimicrobial properties and juice quality. As a colloidal delivery system, nanoliposome provides a novel insight into improve the activity of EPL. In this study, the antibacterial activity and mechanism of chitosan-coated EPL nanoliposomes (CS-EPLLP) against Alicyclobacillus spp. in apple juice were evaluated. It was found that the minimum inhibitory concentration of CS-EPLLP against the strains of A. acidocaldarius, A. fructus and A. acidoterrestris were in the ranges of 0.625–1.25 mg/L, while the minimum bactericidal concentration of CS-EPLLP against these strains in apple juice were 0.625–2.5 mg/L. Compared to A. fructus and A. acidoterrestris, A. acidocaldarius displayed a better resistance to CS-EPLLP. Meanwhile, the modification of chitosan can improve the bactericidal effect of EPL and EPL nanoliposomes. In addition, CS-EPLLP treatment can lead to the inactivation of bacteria cells by causing surface damage, destroying their membrane integrity, preventing the intracellular ATP synthesis, increasing intracellular protein leakage and cells membrane permeability. Furthermore, the addition of CS-EPLLP in the amounts of MBC had no significant effect on the color change, transmittance, centrifuge sedimentation rate and main volatile compounds of apple juice. The prepared CS-EPLLP and established method provides a new insight into the inactivation of bacteria in fruit juice.

An In Vitro Study to Evaluate the Antimicrobial Activity of a Zinc Citrate, Sodium Fluoride, Alum and Xylitol-Based Toothpaste Formulation.

Periodontitis is a prevalent condition significantly affecting oral health. Comorbid conditions, such as diabetes, can heighten the severity of periodontal disease and overall oral health. Therefore, to enhance oral health and manage comorbid conditions, comprehensive periodontal care is essential. This approach could involve using toothpaste containing antimicrobial ingredients in routine oral care. This paper presents the results of an in vitro study analysing the antimicrobial properties of the test formulation containing zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste(Stolin-R).These ingredients work together to help in providing comprehensive oral care by controlling growth of bacteria majorly responsible for periodontal disease and thus maintaining optimal oral hygiene. To determine the antimicrobial properties of zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste formulationagainst key periodontal pathogens through in vitro analyses. The antimicrobial efficacy of test formulationis evaluated through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-dependent antibacterial assessment against key periodontal pathogens, including Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, Streptococcus mutans, and Bacteroides fragilis. The test formulationdemonstrated potent antimicrobial effectiveness against Bacteroides fragilis, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Streptococcus mutans, and Tannerella forsythia, by exhibiting low MIC and MBC. Additionally, significant bacterial reduction, exceeding 99.99%, was observed within five minutes, emphasising its potential as an effective adjunct in combating periodontal infection. Zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste formulation demonstrates significant antimicrobial activity against key periodontal pathogens, suggesting its potential as an effective agent for maintaining oral health and combating gingival infection.

ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF SOME HYDRAZONES SYNTHESIZED FROM NICOTINIC ACID HYDRAZIDE

N’-(2-pyridinylmethylene)nicotinohydrazide A, N’-(4-pyridinylmethylene)nicotinohydrazide B, N’-(2- ethoxybenzylidene)nicotinohydrazide C, N’-(4- ethoxybenzyldene)nicotinohydrazide D and N’-(2-hydroxyl-5-methoxybenzylidene)nicotinohydrazide E, was prepared by refluxing the ethanolic solution of nictonic acid hydrazide and ethanolic solutions of 2-pyridinrcarboxaldehyde, 4-pyridinecarboxaldehyde, 2-ethoxybenzaldehyde, 4-ethoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde in 1:1 mole ratio for 4 hours in a separate reactions. The compounds obtained had a melting point between (120-236 oC) and a percentage yield between (52.38-77.70 %). They were crystalline solids. The compounds' solubility were assessed in water, ethanol, methanol, acetone, hexane, diethyl ether, dimethyl sulfoxide (DMSO), ethyl acetate, and chloroform. The substances were discovered to be fully soluble in DMSO and methanol. FT-IR, 1H-NMR and 13C-NMR were used for the characterization of the compounds. The antibacterial and antifungal properties were tested against Methicillin-resistant Staphylococcus Aureus, Vancomycin-resistant Enterococci, S. aureus, S. typhi, P. aeruginosa, A. nigre, A. flavus, and C. albicans. The zones of inhibitions ranged from 22 to 28 mm and the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were found to be 0.063 mg/mL, 0.125 mg/mL and 0.125 mg/mL respectively. These indicated that the compounds might be good potential drug candidates.

Synthesis and Antimicrobial Evaluation of Some Schiff Base Derivatives

Schiff bases are the nitrogen analogs of ketones or aldehydes, with the carbonyl functional group replaced by an imine or azomethine group. They are formed by the condensation reaction of a primary amine and a carbonyl group, and they are widely employed in industry and have a variety of biological activities. Four Schiff base derivatives were successfully synthesized from benzaldehyde (PC1), anisaldehyde (PC2), 4-nitrobenzaldehyde (PC 2), and cinnamaldehyde (PC4) and tested for their antibacterial capabilities were evaluated against bacteria and fungi. The Schiff base had a high percentage yield of 98.28% (PC1), 95.7% (PC2), 91.6% (PC3), and 98% (PC4), with melting points ranging from 178 -187°C, 183-191°C, 160-164°C, and 195-205°C respectively. All Schiff bases showed activity against Escherichia coli with a Minimum Inhibitory Concentration (MIC) of 62.5ug/ml (PC1, PC4) and 250ug/ml (PC2, PC3). The Minimum Bactericidal Concentrations (MBC) were 125ug/ml, 500ug/ml, and 250ug/ml for PC1, PC2 and PC4 respectively. PC3 showed no bactericidal activity against Escherichia coli. Schiff bases PC1, PC2, and PC3 showed activity against Staphylococcus aureus with MIC of 62.5ug/ml. The MBC obtained was 125ug/ml for PC1 and PC2, while 125ug/ml, and 250ug/ml for PC3. PC4 showed no bacteriostatic and bactericidal activity against Staphylococcus aureus. Schiff bases showed fungistatic activity against Candida albican with MIC of 250ug/ml, 62.5ug/ml, and 125ug/ml for PC1, PC2/PC3, and PC4 respectively. However, none showed fungicidal activity.

THE EFFICACY OF COCOA BEAN EXTRACT MOUTHWASH CONCENTRATION IN REDUCING PLAQUE INDEX IN THE ORAL CAVITY AMONG PRIMARY SCHOOL STUDENTS AT SDN KAYEE LEU, INGIN JAYA SUBDISTRICT, ACEH BESAR

Oral and dental diseases have a high prevalence in Indonesia, with 88.8% of the population experiencing dental caries and periodontitis. Dental plaque is a soft deposit that tightly adheres to tooth surfaces and is composed of microorganisms that contribute to the development of dental caries. Preventing caries and controlling plaque can be achieved through the use of mouthwash, which is more effective when herbal mouthwash containing antioxidants and antibacterial agents is used. Cocoa bean extract (Theobroma Cacao L.) contains secondary metabolites such as alkaloids, flavonoids, tannins, steroids, and exhibits antibacterial and anti-inflammatory properties, as well as strong inhibitory effects against S. mutans bacteria. The objective of this study is to determine the effectiveness of cocoa bean extract mouthwash concentration in reducing the plaque index in the oral cavity. The research methods included laboratory experiments and quasi-experiments with a post-test only control group design. The research was conducted at the Faculty of Veterinary Medicine laboratory, University of Syiah Kuala, and SDN Kayee Leu, Aceh Besar, involving 30 students. Data analysis was performed using ANOVA in the SPSS program. The results of the study indicate that the phytochemical analysis of cocoa bean extract contains alkaloids, steroids, terpenoids, saponins, flavonoids, phenols, and tannins. The Minimum Inhibitory Concentration (MIC) of cocoa bean extract mouthwash on the growth of Streptococcus mutans was observed at a concentration of 1%, and no Minimum Bactericidal Concentration (MBC) was found in this study. The 1% and 2% concentrations of the mouthwash effectively removed plaque compared to the 0% concentration. In conclusion, the use of cocoa bean extract mouthwash is effective in reducing the plaque index. Further research should consider clinical trials to explore its potential as an herbal remedy.

Antimicrobial Activity, Cytotoxicity, and Qualitative Phytochemistry of Leaf, stem bark, and root bark extracts from Prunus africana (Hook. F.) Kalkman

The rise of resistant strains poses a significant public health risk, particularly, in sub-Saharan Africa, where over 50% of global infectious disease-associated deaths occur, highlighting the urgent need for novel, safe, affordable, and accessible antimicrobials. Accordingly, we investigated the antimicrobial activity, cytotoxicity, and qualitative phytochemistry of the aqueous, hydroethanolic, and acetonic leaf, stem bark, and root bark extracts of Prunus africana (Hook. F.) Kalkman, based on its ethnomedicinal information. The results showed the aqueous root bark and aqueous/acetonic stem bark extracts demonstrated significant (p&lt;0.05) antimicrobial efficacy against S. aureus at 800 µg/ml, outperforming other extracts and the reference antibiotic. Growth inhibition zones for most extracts on S. aureus showed a concentration-dependent increase, though not significantly (p&gt;0.05) different. The acetonic root bark extract, particularly at 800 µg/ml, exhibited superior inhibitory effects against B. cereus compared to other extracts (p&lt;0.05), although the positive control antibiotic significantly (p&lt;0.05) outperformed all plant extracts. Notably, none of the studied extracts affected P. aeruginosa and E. coli, while varying effects were observed against C. albicans. Further we observed that the hydroethanolic and aqueous stem bark extracts' exceptionally low Minimum Inhibitory and Bactericidal Concentrations (MICs and MBCs) against S. aureus (3.125 µg/ml). Conversely, the acetonic leaf extract showed higher MIC and MBC values against S. aureus (100 µg/ml). Cytotoxicity assessments using brine shrimp nauplii revealed the percentage mortalities caused by Vincristine and aqueous root/stem bark extracts at 1000 µg/ml, were significantly (p&lt;0.05) higher than those caused by other extracts (Median lethal concentrations (LC50) of 513 µg/ml to 24327.82 µg/ml). Qualitative phytochemistry identified alkaloids in root bark and stem bark extracts, flavonoids, phenols, quinones, steroids, and terpenoids across all samples, with saponins in acetonic root bark and all three leaf extracts, and glycosides in acetonic stem bark, hydroethanolic root bark, and acetonic leaf extracts. These findings highlight the diverse antimicrobial and cytotoxic properties of P. africana extracts, suggesting potential therapeutic applications and emphasise the need for further exploration.

Iron-Based Nanoparticles Synthesis, Characterization, and Antimicrobial Effectiveness

Background: Antimicrobial resistance (AMR) has emerged as a significant and pressing public health concern, posing serious challenges to effectively preventing and treating persistent diseases. Developing new antibiotics with different mechanisms of action is crucial to effectively address challenges in treating infections. A lot of work has already been done on mono-metallic nanoparticles to address the issue.Methods: This study aimed to synthesize multi-metallic iron, silver, and chitosan-embedded nanoparticles using a green approach. Iron, silver, chitosan nanoparticles, and a composite of iron–silver–chitosan was also synthesized. The synthesized nanoparticles and composites were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR) to evaluate their structural parameters. Their antimicrobial efficacy was investigated through MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), and well-disk diffusion assays against Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans.Results: The size of the Cu-NPs, Cu-Ag NPs, and Cu-Ag-CS NPs were found to be in the range of 32-40 nm size with a spherical shape. The nanocomposites' MIC and MBC were calculated to be 125 μg/mL and 500 μg/mL, respectively. The nanocomposites exhibited a range of clear inhibition zones, with a minimum diameter of 12 ± 0.5 mm and a maximum diameter of 22 ± 0.5 mm. Conclusion: The iron–silver–chitosan nanocomposite has been shown to have significant antimicrobial effects in the laboratory environment compared to other nanoparticles hence can be applied as potential biomedical/biological candidates in future.Keywords: Antibacterial; Antifungal Agents; Iron; Silver; Chitosan; Nanoparticles

Bacteriophage Endolysins Antibacterial Effect against S. mutans Isolated from Dental Caries: An In-Vitro Study

Background: Many bacterial infections including dental caries that caused by Streptococcus mutans (S. mutans) were difficult to be treated due to the unavailability of effective antibiotics. Therefore, it requires to focus the attention on endolysin as an antibacterial agent. This study was designed to evaluate the In-vitro effectiveness of specific bacteriophage endolysins against S. mutans isolated from dental caries.Methods: Twenty-five isolates of S. mutans were collected from patients with dental caries attended to Al-Imamain Al-Kadhimain, Medical City Hospital, and AL-Ameen Health Center, during the period from December 2021 to May 2022. The S. mutans isolates were identified by culturing them on their specific mitis salivarius sucrose bacitracin tellurite media (MS-SBT agar), morphological characteristics, gram staining, biochemical tests and VITEK 2 compact system. Seven of these S. mutans isolates were used for the in-vitro study.Results: The bacteriophage endolysin enzyme extracted from the corresponding S. mutans isolate was effective as In-vitro antibacterial agent with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) ranging between (13.63 – 17.83) µg/ml and (17.04-22.28) µg/ml respectively.Conclusion: The endolysin was effective as antibacterial agent against multi-drug resistant (MDR) S. mutans upon growing and testing on culture media.

Antibacterial, Phytochemical and Toxicological Activities of Garcinia kola Extracts against Multidrug Resistant Clinical Bacteria

Objective: The rise in multiple antibiotic resistant microorganisms has led to a decline in the efficacy of many antibiotics, prompting the investigation of alternative solutions such as medicinal plants. To tackle this concerning issue, this study was undertaken to evaluate the phytochemical composition, antibacterial activity, and toxicological characteristics of Garcinia kola extracts against multidrug-resistant bacteria commonly found in clinical settings. Material-Method: The cold maceration technique was employed to extract the root and leaf of Garcinia kola using water and methanol. The extracts were then subjected to phytochemical screening. To evaluate the extracts' potential to inhibit bacterial growth, five multidrug-resistant isolates were utilized in this study. Agar well assay was used to determine the zones of inhibition. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined using the broth macro dilution technique. Additionally, Brine shrimp lethality assay was conducted to determine the lethal concentration (LC50) of the extracts. The extracts were also combined for synergism. Results: The investigation found that the root extract in methanol had the highest yield at 25.58%. All four extracts contained ten out of the fourteen tested phytochemicals. The methanol leaf and root extracts exhibited the highest and lowest inhibition zones of 20mm and 9mm against Staphylococcus aureus, respectively. The MIC values ranged from 250 to 600 mg/ml, indicating broad-spectrum antibacterial activity. The cytotoxicity test showed a range of 33.03 to 126.3µg/mL for the aqueous and methanol extracts. Conclusion: Although Garcinia kola shows potential as a source of antibacterial compounds, caution should be exercised due to its toxic effects.

Synthesis, characterization, and investigation of antibacterial activity of Novel CMC/CuO NPs/CQDs bionanocomposite coating

In recent decades, healthcare-associated infections (HAIs) have become a common problem in healthcare facilities such as hospitals. As a result, researchers are currently developing nanocomposite coatings that are strengthened with antibacterial nanoparticles. In this research, a novel antibacterial bionanocomposite coating based on carboxymethyl cellulose polymer/copper oxide nanoparticles/carbon quantum dots was coated on medical grade 316 stainless steel by sol-gel dip-coating method. The effect of the concentration of nanocomposite components was investigated at four different levels to determine the best ratio with the most antibacterial activity. Structural characteristics of nanocomposite and coating were investigated using different analysis methods. The coating analysis showed that reinforcements are uniformly distributed in the polymer matrix. Antibacterial test of disc diffusion was performed by the Kirby-Bauer method and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) antibacterial test. The results showed that bionanocomposite was effective in the MIC assays against Staphylococcus aureus and Escherichia coli with MIC values of 25 mg/ml and >50 mg/ml, respectively. The inhibition zones for E. coli and S. aureus were 17 and 32 mm, respectively, at 10 μg/disc of gentamicin. SEM images displayed significant and evident alterations in the structure of bacterial morphology, indicating cellular damage.

Green Synthesized Chitosan Nanoparticles for Controlling Multidrug-Resistant mecA- and blaZ-Positive Staphylococcus aureus and aadA1-Positive Escherichia coli.

Antimicrobial resistance has recently been considered an emerging catastrophe globally. The public health and environmental threats were aggravated by the injudicious use of antibiotics in animal farming, aquaculture, and croup fields, etc. Consequently, failure of antibiotic therapies is common because of the emergence of multidrug-resistant (MDR) bacteria in the environment. Thus, the reduction in antibiotic spillage in the environment could be an important step for overcoming this situation. Bear in mind, this research was focused on the green synthesis of chitosan nanoparticles (ChiNPs) using Citrus lemon (Assam lemon) extract as a cross-linker and application in controlling MDR bacteria to reduce the antibiotic spillage in that sector. For evaluating antibacterial activity, Staphylococcus aureus and Escherichia coli were isolated from environmental specimens, and their multidrug-resistant pattern were identified both phenotypically by disk diffusion and genotypically by detecting methicillin- (mecA), penicillin- (blaZ), and streptomycin (aadA1)-resistance encoding genes. The inhibitory zone's diameter was employed as a parameter for determining the antibacterial effect against MDR bacteria revealing 30 ± 0.4 mm, 34 ± 0.2 mm, and 36 ± 0.8 mm zones of inhibition against methicillin- (mecA) and penicillin (blaZ)-resistant S. aureus, and streptomycin (aadA1)-resistant E. coli, respectively. The minimum inhibitory concentration at 0.31 mg/mL and minimum bactericidal concentration at 0.62 mg/mL of yielded ChiNPs were used as the broad-spectrum application against MDR bacteria. Finally, the biocompatibility of ChiNPs was confirmed by showing a negligible decrease in BHK-21 cell viability at doses less than 2 MIC, suggesting their potential for future application in antibiotic-free farming practices.

Relationships among Hydrogen Peroxide Concentration, Catalase, Glucose Oxidase, and Antimicrobial Activities of Honeys.

Honey is a natural sweetener made by bees that exhibits antimicrobial activity, mainly related to its H2O2 content. The aim of this work was to research the H2O2 concentration of 24 Spanish honeys from different botanical origins, studying their possible correlation with glucose oxidase (GOx), catalase (CAT), and anti-Staphylococcus aureus activities (minimal inhibition concentration (MIC), minimal bactericidal concentration (MBC), and percentage of inhibition at 5% (w/v) honey against Staphylococcus aureus), as well as possible correlations among all the analyzed parameters. The results showed that the H2O2 concentration did not depend on the botanical origin of the honeys. There were neither correlations between the H2O2 concentration and the activities of GOx and CAT, nor between GOx and antimicrobial activity. However, CAT and antimicrobial activities were positively correlated. Therefore, CAT could be successfully used as a possible marker of the antimicrobial activity of honeys against Staphylococcus aureus. Furthermore, a linear regression model has been fitted to explain the antimicrobial activity from CAT and GOx activity and H2O2 concentration. Although H2O2 is one of the compounds involved in honey's antibacterial activity, this capacity also strongly depends on other honey components (such as low water activity, acidity, osmolarity, and phenolic compounds). The very high anti-Staphylococcus aureus activity exhibited by all samples could be interesting for commercial honey-based formulations also helping to promote local beekeeping.

Antibacterial activity of the black soldier fly (Hermetia illucens) larva protein hydrolysates against some pathogenic bacterial strains on freshwater fish

The study was carried out to determine the antibacterial activity of protein hydrolysates from black soldier fly (Hermetia illucens) larva (PHBSF) on some pathogenic bacteria including E. ictaluri, A. hydrophila, A. verroni, and S. agalactiae on freshwater fish. The results showed that the tested bacteria were highly sensitive with significant difference (P &lt; 0.05) in diameter clear zone compared to the negative control at the tested concentrations of 20, 35, and 70 mg/100 µL. Particularlly, E. ictaluri was sensitive at all three test concentrations with the diameter of clear zones following 14.0 ± 1.0, 18.7 ± 0.7, and 20.7 ± 0.7 mm, respectively. A. veronii and S. agalactiae were sensitive at concentrations of 35 and 70 mg/100 µL, and A. hydrophila with a clear zone diameter of 14.3 ± 0.3 mm at the concentration of 70 mg/100 µL. The PHBSF was able to kill A. veronii and S. agalactiae with MIC (minimum inhibitory concentration) = MBC (minimum bactericidal concentration) = 44 mg/mL, while E. ictaluri and A. hydrophila were inhibited at MIC 44 mg/mL, and MBC was 88 mg/mL. These results indicated that PHBSF could be potentially used to prevent fish diseases caused by E. ictaluri, A. hydrophila, A. verroni, and S. agalactiae.