Antibacterials - Science topic

I need to prepare a stock of 10 mg / ml erythromycin to check the mic value. I am trying to dissolve 0.1g/10 ml of water but i can't dissolve erythromycin in water.

How can i prepare 10 mg/ml stock solution? Do i need to use a solvent that does not have an antibacterial effect other than water?

I am reaching out to inquire if anyone could recommend a laboratory or research institution that conducts antibacterial testing of textile products, specifically evaluating their effectiveness against Clostridioides difficile, including its spores.

If you are aware of any such facilities or have experience in this area, I would greatly appreciate your guidance or contact information for relevant institutions.

I'm exploring materials that can improve both the durability and antibacterial functionality of electrospun nanofibers, particularly for use in medical applications like wound dressings or air filtration. I'm interested in insights or recent findings on materials with enhanced stability in physiological environments that also maintain long-term antibacterial activity.

Hello everyone!

It has been reported in literature that chitosan has antibacterial properties. I have chitosan available of low and medium molecular weight and I checked their antibacterial activity but there wasn't any. Can you please advice/suggest on this ?

I want to prepare an aqueous solution of Reserpine to test it's MIC. I've tried to use 8% DMSO as the solvent (which will give me final conc. of 2% DMSO during the assay) but Reserpine precipitates (I dissolved 40mg).

I was able to obtain a solution when using 0.5% v/v acetic acid as the solvent (this gives me 0.125% acetic acid during assay). Some of the bacterial samples are showing growth retardation at this conc. of acetic acid.

I purchased Reserpine from Sigma-Aldrich. So, I don't understand why I am failing to dissolve it in DMSO/Water.

Can anybody suggest me a solvent system which is compatible with Cation Adjusted Mueller Hinton Agar and will not give any antibacterial activity?

Dear community

most of phenolic compound is active as antibacterial compound but my compound is not , why ?

Hello everyone, I prepared Biogenic Chitosan nanoparticles after drying I tried to make a solution but, I surprised that the Chitosan nanoparticles didn't solute in acetic acid, how can I solve this problem?

Apparently the lack of tyrosinase:

"Inhibition of tyrosinase can reduce the production of melanin and achieve skin whitening, effectively solving pigmentation (Lall and Kishore, 2014). Therefore, the development of antioxidants, tyrosinase inhibitors, and elastase inhibitors play important roles in solving skin aging and pigmentation" ( https://www.google.com/url?q=https://www.sciencedirect.com/science/article/abs/pii/S0926669020309766&sa=U&ved=2ahUKEwjE4pTd0KyHAxUzHEQIHTzCCpIQFnoECAEQAw&usg=AOvVaw0gD_VQbHW1t1Go0zkPQyIW ).

Ming-Xiang Li, Jing Xie, Xue Bai, Zhi-Zhi Du,

Anti-aging potential, anti-tyrosinase and antibacterial activities of extracts and compounds isolated from Rosa chinensis cv. ‘JinBian’,

Industrial Crops and Products,

Volume 159,

2021,

113059,

ISSN 0926-6690,

https://doi.org/10.1016/j.indcrop.2020.113059.

(https://www.sciencedirect.com/science/article/pii/S0926669020309766)

Abstract: Rosa chinensis cv. ‘JinBian’, a cultivar of Rosa chinensis Jacq., is one of major raw material of rose tea and possesses sufficient plant resources in China. However, the studies on the chemical constituents and cosmetic activities of R. chinensis cv. ‘JinBian’ are almost blank. The main purpose of this study was to evaluate the anti-aging, skin-whitening, and antibacterial potentials of extracts and chemical constituents of the flower by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, elastase inhibition, anti-tyrosinase, and antibacterial assays. Bioassay results suggested both 95 % and 65 % ethanol extracts possessed significant antioxidant, elastase inhibition, and anti-tyrosinase activities. The combined active extract was studied with bioassay-guided fractionation to give a new compound, kaempferol 3-O-α-l-rhamnopyranosyl (1→6)-(2”,3”-O-digalloyl)-β-d-glucopyranoside (1) and fourteen known compounds (2–15). All compounds were firstly isolated from this species and subjected to the above mentioned bioassays. Ten compounds exhibited antioxidant activities with DPPH radical scavenging rate from 63.40 %–94.04 % under the concentration of 100 μg/mL. The antioxidant activities of 1, 2-phenylethyl 1-O-β-d-(6'-O-galloyl)-glucopyranoside (12), vomifoliol (14), and 4, 4'-dimethoxy-3'-hydroxy-7, 9': 7', 9-diepoxylignan-3-O-β-d-glucopyranoside (15) were firstly found with DPPH radical scavenging rate of 83.24 %, 91.10 %, 63.40 %, and 77.75 %, respectively. The moderate elastase inhibitory activities of 12, ethyl gallate (13), and 15 were firstly found with the inhibitory rate of 43.69 %, 43.25 %, and 35.34 % at the concentration of 100 μg/mL. Multiflorin B (3), 12, and 13 showed strong tyrosinase inhibitory activities with the inhibition rate at 43.83 %–55.80 %, comparing with the positive control, α-arbutin (22.15 %). In addition, 1 showed significant antibacterial activity against Staphylococcus aureus with the MIC50 of 8.51 ± 0.26 μg/mL. Compounds 2–4 and 12–14 showed moderate antibacterial activities against S. aureus. Compounds 6 and 13 also exhibited moderate inhibitory effects against Klebsiella pneumoniae. Above results manifested that R. chinensis cv. ‘JinBian’ possessed potential application values in the development of natural anti-aging, skin-whitening and antibacterial products.

Keywords: Rosa chinensis cv. ‘JinBian’; Antioxidant; Elastase inhibitory activity; Tyrosinase inhibitory activity; Antibacterial activity; Cosmetic potential

Would anyone be interested in collaborating on research focused on the antioxidant and antibacterial activity of medicinal plants?

The diffusion pattern of extract in the well is not showing uniform inhibition zone

hi everyone

I have synthesized ZnO nanoparticles with different morphologies but I have problem with keeping them dispersed in well diffusion antibacterial method.

the results are unreliable because of settling down at the bottom of wells and unclear zone of inhibition.

what protocols should I use?

Hi

I have synthesized cerium oxide nanoparticles but they are not showing antibacterial activity at low dose, even at 10 mg/mL concentration there's minute antibacterial activity. Although there is antibacterial activity reported in literature.

Thanks for your suggestion.

The broth dilution assay method was used to find antibacterial efficacy of drug loaded mesoporous silica and free drug in same con.c. is it possible to observe that drug-loaded mesoporous silica has a higher value MIC than free drug MIC against the same bacterial strains s.aureas. The MIC of drug-loaded mesoporous silica stay same for upto long period of times up to months with high accuracy while the MIC of free drug in the same amount gives 4 and times higher value and further decline from the next day of experiment as the drug become settle down and come out of solution. Commonly nanoparticles should increase the antibacterial effect of antibiotic. 1) Kindly give your suggestions what could be the possible reasons 2) what could be its justification 3) also suggest any authentic similar recent studies 4) is it . The release from nanoparticle was 69 to 73% initial burst release then sustained release. The drug is rifampicin derivative. the particle size of drug loaded silica was around 198-230 nm.

Our plant extract samples have shown good results in MIC estimation proving that the compound is antibacterial. But on disk diffusion no proper result was seen. What could be the possible reason or cause?

I have a compound that is low molecular weight, antibacterial in nature, and shows absorbance in UV light on a TLC. So how would I characterize it in nature? For example, is it a peptide? or a phenolic compound or something else. Please give me suggestions regarding this.

I would like to perform the antimicrobial activity for the phenolic compounds of plant extract , which methods is more convenient?

Hi everyone,

When evaluating the antibacterial activity of antibacterial agents, there are two methods commonly mentioned in the research articles, which are agar well diffusion and disc diffusion. I do not know which one to use, as well as the specific conditions for each. Any advice is welcome. Thank you.

We would like to remove our manuscript from your cite because of dublication.

How do you confirm the antibacterial activity is due to phytoconstituents and not due to solvent residues?

How grain size effects the antibacterial properties?

Why in some articles where the antibacterial properties of silver and copper nanoparticles have been compared, in some of them, silver have higher antibacterial properties and in others copper?

we are analyzing activity of an endolysin which has N-terminal domain involved in antibacterial activity. The recombinant protein is not showing activity, and we are wondering that whether His-tag can interfere with its activity, keeping in view the fact that it is also attached at N-terminal of the protein

Please needs to explain: The relationship between the great inhibitory zone (in antibacterial activity) and the lowest or greatest MIC, Why? Thanks

I am working on the biosynthesis of silver nanoparticles, before that I want to Phytochemical screening the particular plants, for analyzed the antibacterial compounds, which technique is suitable for for analysis, I mention the Thin layer chromatography (TLC) and Gas chromatography–mass spectrometry (GC-MS) techniques in my research proposal.

Hi and Hello, I'm currently researching on the effect of plant extract on attachment and biofilm formation of dental plaque-causing bacteria. There are a few questions which confusing sometimes. Hopefully I able to get a clearer explanation regarding this question:

1. Does antibacterial activity reflect the antiadherence properties of the bacteria

2. What is the main difference between the antibacterial and antiadherence

3. Let say if bacterial able to attach to the non-shedding surface but growth is inhibited by the plant extract, does this mean that the extract does not promote antiadhereance activity.

Antibakteriyel aktiviteye sahip bir ekstraktın antibiyofilm aktivitesine sahip olduğunu ve biyofilm oluşumunu azalttığını söyleyebilmek için bulunan değerin MIC değerinden düşük olması gerekir mi? MIC değerinden yüksek ise nasıl yorumlanır?

In order to say that an extract with antibacterial activity has antibiofilm activity and reduces biofilm formation, does the value found have to be lower than the MIC value? If it is higher than the MIC value, how is it interpreted?

I've been synthesizing AgNP for antibacterial effects by mixing AgNO3 & sodium citrate.

After making AgNP I measured the size using DLS, the size of AgNP is about 200~400 nm.

For my experiment I expected that the size is under 100 nm, so I need to make it smaller.

So, is there any method to make it smaller?

(I heard that hydrothermal reactor can reduce the size, but I can't find any reference about reducing the AgNP size by using this)

I want to dissolved my ethanol extract with ethanol to make different concentration for antibacterial test. Or is there another solvent that can be use for dissolving plant extract? And why is it better choice?

I'm doing antibacterial activity assay on several compounds. The problem arose when my compounds only dissolved in 100 % DMSO. I worried if DMSO will affect the diameter of inhibition zone. Would you like to inform or suggest me, what should i do ? Thanks

How would you determine its effectiveness and what are the factors that might affect its effectiveness?

How to monitor the activity of the extract if solvent also has antibacterial effect

For my research paper, I will be studying on the antibacterial, antioxidant, and antitumor activities of the plant species shown in the photo. However, I am not sure of its full scientific name. It was collected in Pandan, Antique Province, Philippines. It has a local name of "libut" and is known as a medicinal plant for headaches and toothaches. Thank you very much in advance.

I am not the author of Functional Titanium Substrates Synergetic Photothermal Therapy for Enhanced Antibacterial and Osteogenic Performance via Immunity Regulation. Who can help me to delete this technically? Thank you!

I used polyarginine to make composite material antibacterial, the first time it was effective, the effect disappeared after repeated, is it because the performance of polyarginine disappeared after water absorption

I have found a Bacillus isolate that showed antimicrobial activity against gram positive and negative ATCC test strain. I have done the test three times where showed same activity against test strains but a few days later it didn’t show activity against the test strains

I want to study the delivery of antibacterial nanoparticles on bacteria gotten from tooth cavities. I have an understanding for in vitro and in vivo studies but I don't really know how to go about an ex vivo study. I will be grateful if aided in this aspect. Thank you

Pure HA normally show s negative effect on antibacterial study. At the same time, can we say that the sample has non toxic property?

Dear biologists,

I would like to know why should we consider gentamicin as a reference molecule to compare the antimicrobial effect of essential oils?

Actually i used plant extract to determine whether there is antibacterial activity or not.

I have performed antibacterial activity using well plate method, measured the zone of inhibitions at 6 different concentrations, and need to calculate the %ZOI and %RSD to determine ic50.. can someone please guide me?

I really appreciate any help you can provide.

I have synthesized silver nanoparticles from leaf extract of a plant (green synthesized silver nanoparticles). I have tested its antimicrobial activity for E.coli. But, zone of inhibition was not recorded. What could be the reason ?

I did extraction of plant and i got crude extraction for petroleum ether, Chloroform, and methanol and I want to check the antibacterial activity for these three extractions. should I prepare different concentrations of solution that used for extraction for checking in a same solvent that I used for extraction or there is another solvent less toxic for that?

My topic is related to antimicrobials, and after testing intracellular ATP levels I found that intracellular ATP is increased at antimicrobial concentrations. In most studies, intracellular ATP levels are decreased after drug treatment and may be related to cell membrane disruption and drug-induced apoptosis. However, I did not find any explanation for the increase of intracellular ATP and the antibacterial mechanism. Can anyone answer my question?

I need to confirm that the antibacterial activity of the lactic acid bacterial strains is by bacteriocins(the antibacterial peptides). Are there any biochemical tests to confirm it?

I just did an antibacterial diffusion test of some plant extract. The result shows no inhibition zone at 100% concentration, but there are some inhibition zones at 50%. Is this a credible result? Is there a theory about this? Is the extract too viscous to diffuse? What should I do?

I need plant extract for use it against S. aureas.

I want to perform antibacterial studies further

We are working with pathogenic bacteria. From the literature we can access to know molecules with potential antibacterial activity, clinical trials, but we are interested in the already approved antibiotics (wide spectrum, and specific for several pathogens). Do you know a database, or a specific mechanism to ask directly at FDA?

Should the size of diameter of the well diffusion be included or to be subtracted from the result in measuring the zone of inhibition?

I have prepared the nanocomposite membranes and I want to evaluate their antibacterial activity. I used nutrient broth and luria broth but the growth was observed in control as well as sample. But In literature PBS is used instead the nutrient broth and growth is inhibited in the sample but not in control. Kindly guide me about the media.

Thank you so much

I am struggling with the antibacterial activity trend of my hot-water extract (obtained from a mushroom). It inhibits the tested bacteria at very low concentrations but significantly stimulates the growth of the bacteria at high concentrations. This trend is the same with any bacterial species being tested. Can anyone please help me understand why this might happen?

- I have used GC-MS to explore the oil components of plants and uncover their antibacterial activity.

- I have shown the results in the table including (Retention time, compound name, molecular formula, and relative content).

- My question is what is the IK of the identified compound should I add to the table, and how it could be calculated??

I know there are several methods for testing antibacterial activity, such as diffusion methods like as agar well diffusion. However, I have an oil extract that will not diffuse into the plates, and I have tried diluting it with other emulsifiers such as tween 80 and DMSO with no success. Do you have any recommendations for what I should do next?

I have an urgent inquiry, I hope someone can help.

For my dessertation Im testing the antibacterial properties of a material on s.aureus bacteria,

In the current experiment, Im using the microplate reader to estimate the concentration of bacteria at OD=600.

I have different samples, some are with the material + the bacteria (100 ul each, total 200 ul), and some other samples are bacteria by itself (100 ul).

My question is how to convert the absorbance readings to concentration while taking into account the volume differences?

Now that I have different ODs, and I have different samples with different sample volume (some are 100 ul, some 200).

After I do the path length correction (which is 0.29 for 100ul, and 0.56 for 200ul) is that it? Can I compare them together?

Or do I still need to multiply those values at 100 ul by 2 to be able to compare them to those at 200 ul?

Also, what do I really get by dividing the absorbance by path length? Is it the concentration? and in what unit?

How can I convert that to bacterial cells/ml?

It’s a bit confusing to me, kindly advice?

I am now engaged in research, the purpose of which is to investigate the antibacterial and antifungal activities of two short peptides that were derived from tobacco and have a length of 150 bp. For this purpose, I am utilizing BL21 and Rossetta DE3 as my E. coli strains. Which concentration should I use to make the zone of inhibition on my Mueller-Hinton agar and LB culture plates broader?

I have conducted an antibacterial assay using the disk diffusion method for aqueous plant extract and gold nanoparticles synthesized using the same plant extract. The result turned out there was a very small inhibition zone portrayed by the nanoparticles, and sometimes it was no antibacterial activity at all. (no clear zone observed). But, when I tested the aqueous plant extract itself, there are promising inhibition zone observed. Theoretically, the green synthesized nanoparticles should have good antibacterial properties as mentioned by many previous researchers. FYI, the bacteria used was Vibrio parahaemolyticus. Does it mean that plant extract is not suitable to react with the gold precursor to exhibit antibacterial properties??

I have quaternized the polymer to confer/enhance the antibacterial properties of the biomaterial. I need help whether increasing the amount or degree of quaternization of the polymer has better effect of antibacterial properties. I have achieved 6.5% of degree of substitution. Is this enough or do I need to increase this?

Hello

The extraction was done by maceration method and kept at room temperature, but the antibacterial results were negative.

1. I need to immobilize microbes, how can I understand that hydroxyapatite chemical is antibacterial?

Although the material I used in the first week of my study showed an antibacterial effect, it did not show an antibacterial effect when I repeated the experiment 3 weeks later.

In antibacterial sensitivity assay, can a lower concentrations of a tested compound give a larger zone of inhibition than the larger concentrations of that compound?

As we all know using Cu, Ag, Ti etc given antibacterial properties. Is there any special metal which can give better then the above

Hi,

We need co-author for performing bio-imaging ( live cell imaging, cyto-toxicity, antibacterial, anti fungal activity study) study. If anybody interested please inbox me.

Hello al

Please i want to manually prepare antibiotic disk for disk diffusion method for an antibacterial plus enzyme inhibitor ( as amoxiclave for example)

My question is that how disk can be prepared? First mix the fractions then put on the disk or individually?

Thanks in advance

If the end application is antibacterial ,does the stabilizing agent used has any role to play?

Silver nanoparticles are prepared commercially in solid form, but i want to make the solution for antibacterial properties through MIC 96 well plates

Our goal is to encapsulate Essential Oil nanoparticles with antibacterial properties to make the application on textiles (fibers).

I would like to know how to interpretate the relationship between energy gap ∆E, calculated by DFT methods, and results of antibacteriel activity using disk diffusion methods of two compounds (comparative study)

I have synthesized Selenium nanoparticles using a plant source. After drying them in Petri plates , these nanoparticles were scraped out. Because of that some of them are found as large thin sheets. It was found to be difficult to reduce their size and also they are not properly suspended in distilled water for antibacterial studies. Is there any solution for these?

Mono- species biofilm such as E.faecalis

Dual - species biofilm such as E.faecalis & S.mutans

What is better for intracanal medicamments antibacterial experiment?

Although it is often said that plant- or mushroom-extracted compounds display their antibacterial activity through a dose-dependent manner, sometimes I observe that it is not practically always the case. Sometimes, an extract show potent antibacterial activity at lower doses, while it is ineffective at high doses. Any suggestion or postulation is welcome!

protein extraction for antibacterial activity

Which methods are best for determining the inhibition zone for bacteria? agar well diffusion method or disk diffusion methods.

I have got following results can you please tell me my result are fine or not if not what I should do to improve my result. Moreover, I haven't seen inhibition zone in that experiment. 10-6 I have got 160 colony calculated as 0.062 is it correct calculation??

There are so many antibacterial NPs available ranging from organic , inorganic to carbon and MXenes. I am planning to do an anti-biofilm study against oral polymicrobial biofilms. I am confused which nanoparticles should I choose from the available options.

I am trying to get the antibacterial activity of the fruit bark extracts. Please if you have any suggestion, kindly drop it.

I have performed antibacterial screening of new compounds (tried different combinations in different concentrations) against oral pathogens, and I got good activity against oral pathogens. Should I select these combinations with good antibacterial activity for my oral care gel formulation?

For Example.

compound A + compound B + compound C = 1ug/ml + 2ug/ml + 1ug/ml

The above combination gives a good antibacterial effect.

Can I consider this combination (with respective concentrations) for my oral care gel formulation?

I have prepared the silver nanoparticles via chemical reduction method using NaBH4. Upon turning yellow color of the solution I stopped the reaction. I got UV vis peak of nanoparticle solution at 400 nm.

But when I centrifuged the solution the pellet is so small that unable to use it for antibacterial activity. I want to ask whether I can use the AgNPs solution for MIC by diluting it with D.W. or pellet is necessary?

Also which medium will be suitable for the growth curve? either nutrient broth or PBS?

I will be grateful for your help.

Antibacterial activity was performed against gram positive and gram negative bacteria using 0.05M HCl as control. in gram positive bacteria control has not shown any significant activity whereas it has shown slight activity against gram negative bacteria . Pls suggest me how can i Calculate the % of inhibition in this case