Questions related to Antibacterial Activity
I need to know the best growing conditions for MRSA and MDR P. aeruginosa.
The incubation time and temperature and the best medium.
Hello, I am going to test different extracts for their antimicrobial activity against MRSA. I made a protocol and I would like it if some of you had any feedback on it.
- Working volume max is 90 uL
- I am going to use an 384 well platte because I am going to test more than 2000 extracts and this is the fastest way.
- Extract is diluted in DMSO
- Needed controls are also tested but not noted in the protocol.
1. Plate the MRSA bacteria on Mannitol Salt Agar containing 5 mg/l methicillin. Incubate 24 hours at 35 °C.
2. Prepare sterile Mueller Hinton Broth and sterile saline.
3. Make the 0,5 McFarland inoculum with the MRSA and sterile saline.
4. Add 35 µL extract + 35 µL MHB + 10 µL inoculum in 1 well.
5. Incubate 24 hours at 35 °C while the growthcurve is being made
Thank you in advance.
Chlorhexidine (Chlorhexidine gluconate, digluconate or chlorhexidine acetate) is an antiseptic that is used in medicine for last 70 years. Is there any experience of Chlorhexidine application to control greenhouse, water, soil contamination by plant pathogens?
I want to study the growth kinetics of bacteria against metal nanoparticles, I have immobilized metal nanoparticles on clay. But I am having difficulty in bacterial growth curve that it is not showing antibacterial properties in the form of nanocomposite. Currently I am using LB and nutrient broth for the study.
Thanks for your help
Chitosan is a natural biopolymer with antibacterial properties and the solution of chitosan is prepared in acetic acid. So, has acetic acid any effect in contributing towards the antibacterial behavior of chitosan?
So far many papers (my literature study) are suggesting that Ultraviolet Radiation on TiO2 induces photocatalytic reaction which makes it give Bactericidal effects on gram positive and gram negative bacteria. Will TiO2 gives bactericidal effect against gram positive and gram negative bacteria without UV irradiation? Kindly suggest me what are gram positive and gram negative bacteria. When a TiO2 based material is implanted into body it does not have the photocatalytic effect inside the body UV light will not pass, then how TiO2 will give Bactericidal effects inside the body?
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.
I am currently looking for a research in PVD coating of medical devices. I am interested on PVD coating of AlTiN for metal cause it has low reflection and is compatible for surgical instrument. I want to doping it with Ag so it has antibacterial effect. But will it make the reflection of material completely change or will it depends on Ag-doping composition?
I am having bacterial strains in the agar plate. I want to extract these strains and store them in glycerol for long-term use. Is there any stepwise procedure for this process?
can I use the spectrophotometer to get the OD for my bacterial suspension before doing a disk diffusion antibacterial test to have a 0.5 McFarland turbidity , and if yes at what wavelength and what value should I get at said wavelength ?
What is the best as chemicals what have antibacterial activity (like silver) for air treatment by tio2 photocatalyist to eliminate different types of bacteria and other air pollutants?
I have some plant samples and I want to check the antiviral activity and Antibacterial Activity. and I want to check it by using bioinformatics.
So I need Suggestions regarding which bioinformatics parameter or software is available that I can use for check by antiviral and Antibacterial activity.
#bioinformatics #antiviral #antibacterial #plants
I want to examine a kind of fruit's extract's antimicrobial effects. At first I want to put it under the UV radiation to prevent the mold or any kind of fungi's and bacteria's growth.
The question is : Does the UV radiation affect on fruit's substances ?
I am performing MIC assays using 96 well plates. I followed the CSLI protocol for standardisation of bacterial cells as follows: Subculture (3 colonies) of 24h bacteria culture into MHB for 3h. I then dilute it with sterile MHB to match the 0.5 Mc.Farland standard and confirm with spectrophotometer at OD600 aiming for an absorbance between 0.08 and 0.13 (They are always between 0.08-0.09). Then, I take 50uL of standardise solution and mix it with 4.95mL of MHB and this is the solution I use for my assay. I take 10ul from the growth control (50ul of Mueller-Hinto Broth + 50uL bacterial solution) and mix them with 9.95mL MHB. Then, I take 100uL of this new solution and plate them in Mueller-Hinton Agar for the colony count.
My colony count of MRSA or MSSA always comes around 20-35 colonies, E. coli and P. aeruginosa always exceede the 50 colonies (around 80-100). What am I doing wrong?
According to the Baier minima, surfaces having critical surface tensions between 20-30 mN/m are considered as foul release surfaces. PDMS or silicone material falls under this range according to literature then why silicone catheter surface allows biofilm formation on to it ?
I did an antibacterial activity of lime peel. I use ethyl acetate as the solvent. The ratio is 1:4. The method of extraction is maceration for 3 days. I stir it everyday. After the 3 days of maceration, next i filter it with whatman filter papers and evaporate it in 40 degree until the extract becomes thicker. I put it in oven 40 degree for 24 hours to make sure all of the solvent has evaporated. The next day i put it in the refrigerator.
I used the extract to test the antibacterial activity with Staphylococcus aureus. I've done it before and it has an inhibition zone, but this time it doesn't have any inhibition zone.. It does have but only a real small inhibition zone (7mm). But according to the journals that I've read, they get like 20-25mm inhibition zone and i wonder what's wrong with my research. I'm still looking the problems, that's why i come here to look for an expert.
Thank you so much
I work with antibacterial surface (copper), we've observed a diminution of activity after some time. We've attributed that to oxidation (to CuII which is known to be less active compared to Cu0 or CuI).
I would like to know if anybody has insight about how I could preferentially have the surface to stay at CuI instead of CuII (would a Cu2O surface be stable?).
We've thought about protecting the surface with an inhibitor (but since the antimicrobial activity comes from the release of Cu+, wouldn't it impear the antimicrobial activity?).
there are ways to get the surface "active" again, by solubilising the copper oxide surface but we would like to keep our surface active as long as possible before having to "reactivate" it.
I have worked recently to investigate the antibiofilm activity of nanoparticles against E. coli.
I have measured the activity via ELIZA using different controls, what is the best method for data presentation in results' section.
There are two interpretive criteria for the results of epidemiological in-vitro anti-bacterial sensitivity studies, namely EUCAST and CLSI. Can I use both in a single study - e.g. using CLSI in an institution and the EUCAST in another institution?
** Kindly note that I'm asking about the mere scientific validity and soundness, regardless of the institution standards.
Has anyone intentionally inoculated their cell culture medium with bacteria and fungi to understand what its bactericidal or growth promoting capabilities are? Using antibiotics in cell culture media is widely accepted as a preventative measure, but this may not be necessary if you have evidence that the medium is already antimicrobial. If you understand your risk points (even if just a select few microorganisms), then you can tailor your prevention measures. Gathering data to see if anyone has also asked this question and has experience and insight through testing, keeping in mind the media formulations for each application may be very unique.
I am doing surface modification of polymer films using plasma in order to improve anti bacterial property.
Thickness of polymer film is 60 micron to 1 mm for different polymers.
I want to test it against E-Coli species.
What are the testing methods suitable to such substrates?
This work is in the direction of developing antimicrobial catheter surfaces.
Thank you in advance.
With kind regards,
Most of the times we dissove extracts from plants or other sources with Acetone or DMSO. Observations show that when relatively non-polar solvents (n-Hexane, Pet Ether, DCM etc) were used during extractions, then the extracts will dissolve best in Acetone or 10%DMSO.
However, during preparations of working solutions and further dilutions on Microtitre plates, the solubility of these extracts decreases and precipitates can be observed upon centrifugation. These precipitates are compounds which dissolved in Acetone or 10%DMSO but they can not stay in solution as the compositions of these solvents get lower. (Maybe they have antimicrobial potentials)
On the other hand, conventional antibacterial agents which are water insoluble are usually solubilized through Synthetic and Formulation approaches eg. Forming their salts. This is not so possible with crude extracts.
If gold standard MIC testing methods such as Broth Microdilution assays are mostly using water based media eg. MHB, what reliable options do we have to zoom in probably potential antimicrobial combounds present in nature but insoluble in water?
Any similar or different encounters?
Hi, I want to check the antibacterial activity of AgNPs. I dissolve AgNPs in a DI water and sonicate it, after that I use well diffusion method to check the anibacterial activity. But AgNPs show no biological activity. Should I use another solvent?
Hi, I am new to bacterial studies, so I have some questions I'd love some input on!
In bacterial studies, I know that zone of inhibition (ZOI) can be used when plating an antibacterial substance, and is often simply reported as a diameter where no bacteria visibly grow. Is it possible that this zone contains alive but non-culturable cells? (Also, given ZOI is just related to the diffusion of the antibacterial substance from the disk, why is it that diameter is considered the 'strength' of the substance and not just its mobility?)
In a similar vein, minimum inhibitory concentration (MIC) is just the minimum amount that prevents further growth, but the cells may either be dead or alive but non culturable, correct? If that's the case, are the MIC and ZOI relatively comparable, since neither differentiate between dead or non-culturable? And if they are comparable, can that comparison be defined quantitatively?
Thanks in advance!
the peptide which i have tested is about 100aa(hepsidin+ hydrophobin) and i haven't seen any inhibition zone, can it difuse through the muller hinton agar?
I want to do MIC and MBC test on streptococcus mutans, i have muller Hinton ,and BHI medium, is there any way that i can do this with out using blood?
the problem is I cant find blood in my university.
The compound Drosophilin A is known to have antibacterial and antifungal activity (Anchel et al. 1955; Anchel 1952; Kavanagh et al. 1952). Its methylated analog, Drosophilin A methyl ether, also a fungal metabolite (Teunissen 1999), has no reported -as far as i know- any biological activity.
- DA IUPAC Standard InChIKey: XIWJLPHQDBDOAN-UHFFFAOYSA-N
- DAME IUPAC Standard InChIKey: HICARXIPJINIRA-UHFFFAOYSA-N
- Anchel 1952: bit.ly/2DpFB2U
- Kavanagh et al. 1955: bit.ly/2FBypU7
- Anchel et al. 1955: bit.ly/2PuxBVA
- Teunissen 1999: bit.ly/2FpkC2M
Chemical structures from NIST Chemistry WebBook, SRD 69
The above question is for efflux pump inhibitors with or without antibacterial activity
how will the above choice hold good for biofilm inhibition??
What differences between Kirby-Bauer test and disk diffusion test? is it the same thing? Both of them use filter paper impregnated with a standard of sample extracted, then placed onto an agar plate that was previously inoculated with the test microbe. These method was found to be a simple, cheap and reproducible practical method.
I need some papers( both research + review) where plant extracts been used both for both antibacterial and antibifilm candidate.
Secondly, any database of secondary metabolites having antibacterial activities..
Thanks for your co-operation
In Disc diffusion susceptibility test, on sterile nutrient agar plate broth culture of the test bacteria was swabbed and dried, and 4 sterilized discs, each of 6 mm diameter (prepared in the laboratory from Whatman’s No. 1 filter paper), were placed on 4 different sectors and marked. Thereafter, the discs were soaked with four different concentrations: 20, 35, 50 and 65 μl/disc of ethanolic Bakul Leaf Extracts.
After incubation, ZDIs values obtained around each of the discs were measured. But, clarity of inhibition area lost due to chlorophyll like contents present on the leaf extracts as green tint. In that case, What will be the clarity enhancer procedure without hampering the experimental actuality ?
The next stage of my project requires growing single species biofilms in 96 well microtitre trays by placing PCR plates with the 'pegs' sitting in the bacteria culture to grow biofilms on them, as described in this paper: " Antibacterial Activity of Blue Light against Nosocomial Wound Pathogens Growing Planktonically and as Mature Biofilms" by Halstead et al.
However previous groups have struiggled due to the coned shape of the pegs, are there any with flatter bases and/or more cylindrical rather than conical pegs?
i want to specifically assess the activity of the extract against cough-causing organisms.
I have 100 mg of peptide antibiotic i.e colistin. Potency is >15000 U/mg and solubility is in water (50 mg/ml according to manufacturer's instructions). As potency is given in units, so converting (via online conversion calculators) it into micrograms, it is 1U=731.7 ug in case of colistin. As W=C*V/P formula does not apply on peptide antibiotics. So, how should the stock solution be made if my final testing concentration is 128 mg/L but first I need to make 20 X of this concentration. (128 mg/L would be the concentration in 150 ul volume). I'll appreciate if anyone can help in this.
I have a non polar compound (curcumin analogue) that insoluble to water, but soluble in pure DMSO. So, for antibacterial test purpose, I tried to dissolve it in DMSO 100% then add with aquades until the DMSO concentration is 10%, but it still insoluble, so I add 4 drops of tween 20. Is it okay to use that method to dissolve my compound in antibacterial activity test? Or what should I do with my compound in order to dissolve it?
I am intending to perform antibiotic susceptibility assay on cultures of Staphylococcus aureus by broth microdilution method, using resazurin sodium dye as a marker of cellular viability. For this purpose which media should be preferred? I have some references suggesting the use of Mueller-Hinton broth. Need expert opinion on this.
I am working with some fern antimicrobial properties and I would like to know the range of the best concentrations that I can prepare my plant extracts before I can be sure they have performed best and can compete with conventional drugs for such microbial conditions.
Actually, I have extracted antimicrobial agents by solvent extraction with ethyl acetate. Now, I want to know that does ethyl acetate alone has any antimicrobial activity or not?
What I have observed that Ethyl acetate extract has antimicrobial activity, now actually, I want to confirm that does ethyl acetate (organic solvent) has the antimicrobial activity or not?
How do nanoparticles act on Candida albicans? Like for gram positive bacteria, the nanoparticles penetrate the cell wall and kill the bacterial cells. Is the same mechanism followed by nanoparticles while acting on fungus like C. albicans?
In the commercial antimicrobial discs, some of the discs the company provide different concentrations. Does it matter? Since this is not a quantitative method, it should be fine with whatever concentrations, right?
I am working on the screening of marine natural products with potent antifouling activity. I want to test the initial crude extract by coating the same on metal or glass panel to expose in seawater. What kind of “BINDER/ADDITIVE/GLUE” will be used to coat the crude extract on metal panels to test initial antifouling ability?
So when using MIC we are basing our numbers established on a bacterial concentration. For instance we say the mic of citric acid for salmonella is 1000ppm. We did the test at a starting bacterial concentration of 10^5
We measured final results through absorvance and calculate the percentage of growth inhibition that happened.
If we have different bacterial concentrations can we infer the value of the mic based on the absorvance values?
I mean for a bacterial concentration of 10^5 the mic was 1000ppm what would the mic be if the bacterial concentration would be 10^7?
The compounds are metal complexes wherein a Nickel compound has shown effective antimicrobial activity against MRSA strain, Vanadium compound has shown antidiabetic activity and copper compound, a very good anticancer activity.
I need to know if performing DPPH assay for determining the antioxidant activity add on or give an extra proof for the above said activities?
I am currently researching about the antibacterial capability of certain proteins and protein hydrolizates against microbial cultures. We do not have any reference about the protein concentration of my matrix that could have antibacterial activity. Anyone could reccomend me what is the best dilution strategy for the determination of MIC from unknown proteins and protein hydrolizates?
As written in the title, I would like to load zeolite onto a sterile paper disc for testing its antibacterial activity using the technique known as Zone of Inhibition. Can I redisperse Zeolite in a solvent, for instance, dichloromethane, and then directly drop the suspension onto the paper?
Like I have more than 100 papers on silver nanoparticles and I have not seen ames assay, invitro DNA damaging and hemolysis potential of synthesized nanoparticles and their starting material. Even if you are using green material there are chances of cytotoxicity... Then why are not they checking?
comment from your knowledge and experience!
I am working on a study to evaluate the antibiofilm activity of compounds already injected in polypropylene, but I do not know what to compare their activity, do you know some material or surface that can use as a reference antibiofilm?
thank you very much
I will be glad to receive a listing of all the scientifically appropriate experiments to conduct in order to indicate the anti-microbial activity of plant extracts. This includes experiment from extractions to sensitivity tests.
I tested for the presence of an anti-bacterial activity of a sample against E. coli using disk diffusion assay.
Two different concentrations i.e., 2 mg/ml and 4 mg/ml were used and found to exhibit anti-bacterial activity as was evident from a circular zone.
PROBLEM: Around the circular zone, few colonies during the initial hours around the zone appeared and later no colonies showed up.
I hypothesized that the sample inhibits the bacteria lately which is why bacteria could grow in that inhibitory zone.
If I have to test this what are the experiments can I perform to come to the conclusion ?
Your suggestions and solutions are highly awaited.
I have attached the image of my Bacterial plate.
I have synthesized silver nanoparticles by using bacterial extracellular components as the reducing agent. After confirming the presence of AgNPs in our samples I'v tested the resulted colloid in bacteria but I didn't get any bactericidal action. any help with this issue please?
I am planning to isolate marine actinomycetes from a specific area and identify them and their secondary metabolites.
Can somebody answer how to study antibacterial studies (practically) of some polymer blends in labs. what are the things required , and how to set experiments. I will be grateful if u can spend some time for me to explain.
Evaluating the antibacterial activity of cassava leaves and roots in Sri Lanka.
Upon sample collection, the leaves and roots were washed and sun-dried after which they were extracted with methanol. The extracts were concentrated to give crude semi-solid extracts. These were then resuspended in distilled water to give a initial concentration of 1mg/ml which was further diluted to 0.75, 0.5 and 0.25mg/ml.
Disk diffusion assay was chosen to test for the antibacterial activity against S. areus and E.coli. Gentamicin and distilled water were used as positive and negative controls respectively.
Since no zones of inhibition was seen except at the PC, considering the concentrations to be too low, further test was carried out with concentrations of 200 and 100mg/ml. However, these also did not give any zone of inhibition except at the PC.
Thus, as another attempt, fresh samples were again collected, crushed with mortar and pestle and homogenized with distilled water, they were then centrifuged and disk diffusion assay for both the supernatant and the pellet was carried out against S. areus. However, this too did not give any zone of inhibition though at its maximum concentration.
Considering this could be due to less volume that was impregnated in the discs, well diffusion was opted. However, this too did not give any zones of inhibition.
Since there are articles from other countries like Sudan, Malaysia, Africa, India and Thailand giving positive results, can I conclude that the cassava obtained from Sri Lanka does not have any antibacterial activity or is there any other attempt I can go for?
i want determine antibiotic susceptibility of biofilm-state bacteria to compare with planktonic-state bacteria. i searched some papers and met some description like MBEC, "MBEC" is the same meaning with "MİC of biofilm cells". and is there any method for Escherichia coli.
I have antimicrobial activity in the nutrient and L.B broth but when i try to extract it with different organic solvents like Ethyl acetate, butanol, n-Hexane, Chloroform etc, there is no activity in the extract and the activity also losses from the broth. Please guide me what to do in this case.
I wanted to check the antimicrobial property of my plant extract. Just to check the same I did disc diffusion assay for the concentrated plant extract using Nutrient Agar medium and E.coli culture. After incubation for 24 hours, the zone obtained was transluscent immediately after the disc followed by a transperant. When I checked with the images on google, the pattern was similar to anti quoram sensing property assay (qualitative). So, I donot know whether I have got the zone of inhibition for the growth or anything else is there. I am attaching the picture of the analysis. Please help me to analyse the same
I need a protocol (without automatization) in order to do antibacterial effect of nat products in vivo with C. elegans model. Thanks
Tea Tree oil (TTO) is available in many brands by several famous companies with the promise that it cures most of the skin ailments like Acne and Psoriasis because of its antibacterial and antifungal activity. Australia is the biggest producer of TTO. It is claimed to be active against MRSA a deadly pathogen. Besides, it has been incorporated in products as antimicrobial laundry freshener, antidandruff shampoos, acne face wash, natural deodorant and household cleaners.
Our study on 550 strains of bacteria causing topical infections, Candida albicans for comparing TTO with 8 topical antibiotics (polymyxin B sulfate, gentamicin, nitrofurantoin, tetracycline, chloramphenicol, cotrimoxazole, ciprofloxacin, and novobiocin) revealed that gentamicin was the most effective antibiotic followed by chloramphenicol, ciprofloxacin, nitrofurantoin and polymyxin B inhibiting 87.1%, 84.8%, 76.8%, 75% and 72.8% strains, respectively. Tea tree oil (at 1 μL/ mL) could inhibit the growth of 20.5% strains. Only 10% of multiple drug resistant (MDR) were sensitive to TTO. Though TTO is a broad-spectrum antimicrobial active on 26 out of 44 genera of bacteria is a less promising antimicrobial than antibiotics on MDR strains. The TTO is to be said very effective against staphylococci but this study revealed that in vitro only 12% staphylococci were sensitive to TTO. It is claimed that 5% TTO formulations are highly effective, no doubt in vitro 5% TTO can kill many of the bacteria but when applied to skin and bacteria causing infection are hiding a little deeper in the skin and at that site how much concentration of TTO reaches and in that concentration, how toxic is TTO to host cells?
We have observed some synergy between herbal antimicrobials and antibiotics. It may be due to inhibition of efflux pump by herbal antimicrobials or due to some other kind of interaction.
How good this combination can be exploited clinically.
A nano-compound was synthesized by degrading the polymer and combining it with transition metal. The solubility of resulting compound is very less. Now I am planning disc diffusion method for determining the antibacterial activity of this compound. For this, the compound should be completely soluble.
Can you please suggest how I should solubilize this compound or is it possible to determine the antibacterial activity with partially soluble compound or is there some other method for this?
a mixture contains 45mL of HBSS and 5mL of anti-anti and is filtered, and then stored at 4 degrees for about 6 months. It doesn't show any visible contamination, but freezes instead. What does it mean?
Hello every one
I made the synthesis of some new compounds and I want to evaluate their biological activities such as anticancer, antifungal and antibacterial activity.
The question that arises here, if these compounds do not degrade in the biological medium (human tissue, fungal, bacterium) that pass before reaching their target?
So, I would like to know if there is a scientific program that can predict this property (stability of a molecule in a biological medium).
I am trying well diffusion method but my samples doesn't show antibacterial activities no zone is formed. what could be possible reasons?
is there any modification for sample to show activity?