Questions related to Bacteriology
We are currently using densitometers from biomerieux to prepare bacterial suspensions. We are wondering if there are any tubes with sterile NaCl solution available on the market other than biomerieux ampules that fit this type of densitometer?
What kind of tubes are you using?
We often use hundreds of them and we feel it is just a waste of money, we were looking for other glass ampules or tubes that are flat-bottomed and not too high so for example you can withdraw some of the suspension with an automatic pipette as well but we can't find anything...
I would appreciate any kind of advice on this!
I'm trying to figure out the colony morphology characteristics that one should be skeptical of when deciding whether two colony types on the same plate represent morphologic variations of a single genetic organism or two distinct genotypes when mixed culture is a possibility.
I know that colony size is one, as "Relative colony size is driven by the location of adjacent competitors" *
Another one is colony color, as shown in the figures.
What about other characteristics: Form, margin, elevation, etc?
*Chacón, J.M., Möbius, W. & Harcombe, W.R. The spatial and metabolic basis of colony size variation. ISME J 12, 669–680 (2018). https://doi.org/10.1038/s41396-017-0038-0
What is the difference between the following three bacteria in terms of bacteriological tests?: Achromobacter spanius, Achromobacter deleyi and Achromobacter kerstersii?
I have a sequence of 16s which 100% Mach to this three bacteria ; how can I find which is my bacteria by bacteriological tests?
We are working on Biofilm and Quorum sensing genes of E.coli, we suggest some of reasons maybe:- Contamination, Annealing Temperature, Melting Temperature, DNA Extraction mistakes in the Techniques, we identified them by biochemical tests to be sure the isolates are E.coli, but now we are collecting samples from the beginning and doing the procedure again
Hydrogeochemical and bacteriological investigation of groundwater in Agbor area, northern Nigeria
Hydrogeochemical and bacteriological investigation of groundwater in Agbor area, southern Nigeria
So, when I tried to id a Gram (-) bacilli from clinical spicmens. I tested oxidase disc test and sometimes, I ended up seeing oxidase positive and lactose ferment speices in many specimens. Most of the clinical specimens came from wound infection of pediatric and orthopedic patients. Does anyone encounter similar situations?
It is more often than not does negligence cause the immediate risks to our laboratory personnel and to our surroundings, needless to say, how can we reduce these clerical and technical errors to prevent any more trouble?
Handling bacterial specimens provides a higher risk for cross-contamination, and there are different methods to avoid it. What are the most effective to date that is used commonly by laboratories?
Keywords: Bacteriology, Clinical Laboratory, Cross-contamination
I have a two part question.
Why when it comes to bacteriological testing for a clinical sample, here blood, it is crucial to get the adequate volume of blood from the patient and not a smaller amount? Why is it important?
And why when it comes to infants and children, a smaller volume of blood is required for a bacteriological test than for a adult? (But other than it's a small baby or infant and we can't take lots of blood.)
Some Streptococcus groups are beta-hemolutic on blood agar, is it because of toxins? What toxins exactly causes the beta-hemolysis?
If it is then how are these toxins affected by the presence of oxygen and how it is regulated? Since they can be facultative anaerobes.
Thanks in advance.
We get dead animals for necropsy frequently. Sometimes, the carcasses are frozen. We thaw the frozen carcass to conduct the necropsy.
For bacteriological culture, can I use frozen (at -8°C or -20°C for 2-4 days) tissue or carcass at necropsy (lung, liver, stomach, intestine, kidney)?
What can be the problem if frozen–thawed tissues are used for bacterial culture?
Can I consider the culture positive or negative result dependable?
Can anyone give me a reference regarding this issue for further study?
I have an extract that is more effective at lower concentrations against tested strains of bacteria. I have done some research and some says it might be to do thickness of the extract that doesn't allow it to diffuse into the plate equally. but to the naked eye it doest seem that way.
Any suggestions would be greatly appreciate it.
Despite being a gram positive bacteria, Clostridium tetani can produce a greenish fluorescence color on MacConkey medium containing neutral red indicator, why is that?
Blood can be the most common type of clinical samples when it comes to bacteriological tests, diagnosis, culturing..etc from a clinical point of view, why is that?
The obvious answer seems to be YES! But a reviewer asked me to find a reference. Anybody knows of any work that compared the EPS of biofilms and colonies?
Or maybe I'm missing something and EPS is a biofilm-only feature that doesn't exist in regular colonies?
If it helps, we're talking about Enterobacteriaceae species like E. coli, K. pneumoniae and P. mirabilis
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?
I want to start my Phd, I am interested in medical bacteriology and molecular biology.
I am interested in infectious diseases, antibiotic resistance, and vaccine development
can you advise me on the most important topics to connect the two fields?
Dear academic colleagues!
Sorry for my ignorance in the field of bacteriology!
I need to know if S. mutans and sobrinus are oxidasse (cytochrome) +ve or-ve? Some internet sites reports that S. mutans is -ve, others +ve. Regarding S. sobrinus litle is written.
I believe that a lot of you can easely answer this question.
I know that we should use API 20 NE for the identification of pseudomonas aeruginosa, but I don't have API 20 NE strips in the lab.
Calling SEM experts and those with SEM in bacteriology. We ran an air dried layer of LB cultured bacteria over the SEM stub. This is like some canalicules being witnessed. can this be bacteria. ON LB agar, we see swarming effect of this bacteria. Please help?
If I want to transport the sterilized laboratory glassware and bacterial culture in petridshes from one lab to another lab of a short distance then what will be the complete best strategy to avoid the contamination??
Hi expert out there!
I'm using crystal violet staining to determine gram +ve and -ve bacteria, which is a very traditional method, but at the same time, I noticed that crystal violet also can use for cell viability tests. It seems that the sample that I'm going to use involves cells too, so my question is how can I minimize the chance for the cell to get stained but instead only the bacteria (ie increase the decolorization time will help?)?
Thanks in advance!
I'm looking for an alternative for bacteria-bacteria interaction. I'm using transwell to study interaction between 2 bacteria, but I have a lot of contamination problem. I've been looking for dialysis protocol but I don't know if it's a good idea. Any clue?
I am looking for the protocol to calculate MIC and MBC by broth microdilution method but I am unable to get a suitable protocol. In papers, they have given the reference of CLSI but when I am opening the reference, sample copy is being displayed which is not having the methodology. Can somebody provide me the detailed protocol for MIC and MBC calculation or share the link of CLSI which is having the complete protocol.
Bacteriology pollutant is commonly observed in river because it is open to the atmosphere and subjected to pollute, despite wastewater effluents in to the river. Chlorine commonly uses for removing bacteria and pathogens contaminants in water, but it has some side effects on human health. Which methods of treatment should be used instead of chlorine without negative impacts?
How can I know the stationary phase of growth of several bacteria?
We are aiming to collect exoproteome of several bacteria. We know that the ideal time to collect exoproteome is during the stationary phase of a particular bacteria. Perhaps we have many bacteria and there is very limited literature on few bacterial stationary phase. Further the information is not available for many bacteria. Could someone suggest us any manual or a paper which describes stationary phase of these bacteria.
I want to predict operons on entire bacterial genomes (already annotated). I used to use operon-mapper ( https://academic.oup.com/bioinformatics/article/34/23/4118/5040321), which is great but it has been "under maintenance" for weeks now and I really need one now.
MicrobesOnline doesn't support private genome hosting anymore and I think that the DOOR website is now down.
If you know any other tool, online or not, that would allow the genome-wide prediction of operons in complete, annotated bacterial genomes, that would be of great help to me.
There are a few reports about possible genetic control of tissue specificity of Xanthomonas spp:
Bogdanove AJ, Koebnik R, Lu H, Furutani A, Angiuoli SV, Patil PB, Van Sluys MA, Ryan RP, Meyer DF, Han SW, Aparna G. Two new complete genome sequences offer insight into host and tissue specificity of plant pathogenic Xanthomonas spp. Journal of Bacteriology. 2011 Oct 1;193(19):5450-64.
Lu H, Patil P, Van Sluys MA, White FF, Ryan RP, Dow JM, Rabinowicz P, Salzberg SL, Leach JE, Sonti R, Brendel V. Acquisition and evolution of plant pathogenesis–associated gene clusters and candidate determinants of tissue-specificity in Xanthomonas. PLoS One. 2008 Nov 27;3(11):e3828.
Is there any certain gene confirmed as regulator of tissue-specific reaction of xanthomonads?
The efficacy of antibiotic therapy for Helicobacter pylori is highly variable in the world. It depends on bacteriological, environmental and host factors. First- line antibiotic drug-resistance is increasingly seen in some regions of the world. Every time the introduction of new therapeutic schemas are necessary for overcome this problem. According to your personal experience what is the best antibiotic therapy schema in you practice and what is your protocol for confirming eradication? Best regards to everybody
We shall collect biopsies from skin/hoof of animals for bacteriological microbiome analysis. We need suggestions on DNA extraction kit that may be used for this. We prefer to keep the biopsies in a DNA stabilizing reagent (RNAlater), so the kit have to be able to deal with that? If not, we need suggestions on alternatvie storing of biopsies before extraction - as transfering them directly onto ice is not possible.
Trying to make Terrific broth. i make total 100ml of TB. 90ml TB and 10ml TB salts. Autoclave separately and cool down below 50 degrees. and add TB salts . But every time i add TB salts the entire media gets extremely turbid. even if i add 1 ml of TB salts same thing happens....what could be the reason??
my data comprises of both physical, chemical and bacteriological data
Fe-BABE conjugation can be used to find out the DNA binding region to the enzymes but Fe-BABE conjugation is a tedious process (mostly because of construction of single cysteine derivatives).
Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. They can be found in yogurt and other fermented foods, dietary supplements, and beauty products.
what is your suggestion about an appropriate and trending titles for Medical bacteriology Ph.D. seminar?
I'm working with both facultative anaerobes and obligate aerobes. I was wondering do SIM and/or MIU tests work if the bacteria are aerobic? If not what tests should I do in order to find out whether my bacteria are motile? Hanging drop method doesn't work for me, I've also tried simple wet mound method with some dye to help visualization.
I propose to determine factors influencing bacteriological and clinical cure in dairy cows with clinical mastitis after treatment with antibiotics. I propose to follow clinically healthy (i.e. without clinical mastitis) lactating cows for the development of new clinical mastitis and also for cure (Bacteriological and clinical cure) of the affected animals after treatment. But there is no any comparison group, i.e. no control group or treatment group (as the antibiotics are also factors to be studied with respective to their type, dosage and others). In addition with this, it is new to be conducted in my country (Ethiopia) which is seems to me difficult to take the previous proportions conducted in developed countries as a proportion estimate in my study due to management or other facilities difference. So my questions are:
1. How do I determine the sample size?
2. Could I use the 50% proportion as proportion estimate in this case?
This is my first time working with thioglycollate broth and based on everything I've found I am not a 100% sure what this type of growth represents. I can see a growth on the top, then a line of no growth and then dispersed growth almost to the bottom of the tube. Would this be typed as facultative anaerobic bacteria?
I have two strains from a single patient. Both have been confirmed as Ps. aeruginosa by PCR. One of them produces a dense brown pigment but the other produces no pigment....has anyone come across this before?
This is a carbohydrate fermentation test I did with several bacterial species. I used Phenol Red as an indicator and added 1% of different carbohydrate in each tube. This is after 23 hours incubation at 25 degrees Celcius. We incubate at this temperature, as my bacteria grow better at this temp. Some of the samples turned out like this. I don't really know how to interpret these? Can anyone help?
Microbial biofilm is the formation of sticky adhesion layer attached to the surfaces of animate or inanimate objects
Can someone give me a reference where I can find the definition of log reduction of bacteria (due to UV-C irradiation) in terms of disinfection? In other words, how much log reduction is required for disinfection?
A group of bacteria (containing several taxa/genera), with ability to degrade a contaminant under specific conditions (pH, temperature), was screened from soil (environmental sample) through sequential transfers and sub-culturing in liquid growth medium. What should I say it, a mixed culture or consortium?
I want +carry out some susceptibility tests of different bacterial species and was wondering if you could substitute the beef-infusion by meat extract. Or if the two things are the same anyway? What´s the difference between meat-extract and meat-infusion (as the second is an aqueous extract)?
I am really confused!!
Gram-positive or Gram-negative bacteria, which one has a higher surface negative charge? why?
I have been growing E. coli host in SM6 medium for fermentation. During the run, I did microscopy and found long filamentous rods, which are Gram negative. I have started searching literature for morphological changes in E. coli due to stress. The antibiotic marker I use is tetracycline.
I'd really appreciate some help here...
i need good topics from general microbiology, virology, bacteriology, mycology, microbial food toxicity, any topics on public health. i would prefer the topics to suit developing countries. thanks in advance
Benzalkonium chloride (BKC) is Quaternary ammonium compound(disinfectant) and cationic surafctant...used in pharmaceutical industry so we want to test Bacterial endotoxin in (BKC). We did LAL method(limit:2.5 EU/ml, Lysate sensitivity 0.03) but didnt get positive control(No gel formation) and also check by Kinetic chromogenic method but not get the results as BKC have strong disinfectant property.Tween 80 and Lecithin neutralizes this activity so can we use that in LAL method( In dilutions or wherever applicable) and how?
I have tested several media for investigating P-solubilization of Bacillus isolates but none has produced any results yet. I have tried Glucose yeast Agar (GYA) with following incgredients
Glucose (10 g), Yeast extract (2g), Agar (15g). After autoclaving I added the K2HPO4 and CaCl2 (10% solution of each) and poured the media.
I spot inoculated the isolates but didnt see anything even after 7 days.
Then I tested Pikovskaya/s medium with following recipe
Yeast Extract 0.50g
Calcium Phosphate (instead I used Calcium phosphate monobasic) 5.00g
Ammonium Sulphate 0.50g
Potassium Chloride 0.20g
Magnesium Sulphate 0.10g
Manganese Sulphate 0.0001g
Ferrous Sulphate 0.0001g
Even then I could nt see any halo zone.
I have also used NBRIP-BPB medium (Glucose, 10g; Ca phosphate monobasic, 5g; MgCl2.6H2O, 5g; MgSO4.7H2O, 0.25g; KCl, 0.2g; Ammonium sulphate, 0.1g; Bromophenol blue, 0.025 g; Agar 15g). For NBRIP-BPB medium I adjusted pH to 7 with 10N NaOH but precipitates appeared in the media.
Can anyone let me know where is the problem in my methodology?
For the screening of microplastic biodegradation, i make a culture of bacteria on mineral salt agar(bacteriological agar) with microplastic as the sole carbone source. But in the negatif control (the same medium without carbone source) there is a developpement of some colonies. I can not understand how this bacteria can multiplied without carbone source.
Unsuccessful experiment with ruthenium red
To distinguish between EPS-producing (S. thermophilus) and nonproducing (E. coli) cells, M17 agar medium containing 0.08% ruthenium red and ruthenium red milk plates (RRM) (consisted of 0.5% yeast extract, 10% skim milk powder, 1% sucrose, 1.5% agar and 0.08 g L- of ruthenium red) were used. After incubation at 37 ºC for 24 h and 48 h, every strain gave whitish (maybe pale pinkish) colonies. It was unclear.
Stock solution: 0.0877 g of ruthenium red [Ruthenium(III) chloride oxide, Alfa Aesar] in 8.77 ml distilled water was sterilized.
0.8 ml ruthenium red stock was added to 100 ml molten M17 and 100 ml molten RRM agar just prior to pouring it into petri plates. What could be wrong with that?
I have read and heard of many studies discussing dangers of raw food diets for cats, but less on the evidence of their impact on the health of cats.
Surely a diet closer to a cats natrual wild diet is preferrable to highly processed and cooked foods, including a high amount of vegetables and grains? If they hunt and eat live prey then why is raw feeding a problem? Is it because it it produced commercially and manufacturing practices can introduce pathogens? Also, would different companies not also have better or worse practices that contribute to a less infected product?
I would love to see more brands tested and more replicates found, and more research done on the presence of pathogenic bacteria in cats as a direct result of their diet, raw or no.
Water bacteriology analytical laboratories need to use control organisms (negative - and positive+), to get ISO 17025 accreditation. For this purpose, E coli can be used as total coliform (+) as well as E Coli (+) . As most of the E coli strains are non-pathogenic and can be used safely.
Pseudomonas aeruginosa is used as total coliform (-) and E. coli (-) while, Klebsiella pneumoniae is used for total coliform (+) and E.coli (-)
As Pseudomonas aeruginosa and Klebsiella pneumonia are pathogens, to avoid risk of infections in water analysis laboratories, to use as control organisms, can any expert Microbiologist recommend non-pathogenic strains of these organism or any other alternative non-pathogenic organisms suitable as control bacteria?
Hi, I made 40% urea broth medium(Biolife Italiana) to find out the presece of helicobacter pylori in gastric biopsy but this medium responds very slowly for positive biopsy (about 2 hours) while this medium has been tested with pure proteus mirabilis bacteria and give a very fast reaction for a few seconds. My question is why this medium don't work quickly on the biopsy sample and what is needed for a rapid reaction?
For the clear plaques, I can understand it's a complete lysis, no bacteria are growing in that aera any more. But how to explain the turbid plaques? Is it the phage lysed some of the bacteria, but the rest got resistant to the phage, which led to a incomplete lysis? And how about the halo plaques?
And why the plaques have certain size, but cannot enlarge limitless?
Bergeys manual of systematic bacteriology shows a table in which there is a - sign in front of urease hydrolysis , for bacillus subtilis and bacillus cohnii. I want to ask does that mean these bacteria are non-ureolytic?
The modern system of classification is based on evolutionary relationships among organisms – that is, on the organisms’ phylogeny. Classification systems based on phylogeny organize species or other groups in ways that reflect our understanding of how they evolved from their common ancestors.
Some companies claims they have bacterial concentration to the tune of
1 x 10^11. But in our culture technique we could maximum culture 1 x 10^9 which is (1 billion cfu/ml)
Mannitol Salt Agar is the most common technique used to differentiate CoPS from CoNS. But I am curious to know any other techniques or media which can be used to differentiate CoPS from CoNS on an agar plate. Kindly suggest.
Acc to a new classification given by Spatafora et al. (2016) mycorrhiza have been placed in zygomycetes as a sub-phylum- Glomeromycotina (C. Walker & A. Schüßler) Spatafora & Stajich, subphylum and stat. nov...How acceptable is that? Or we still refer to the classification of Glomeromycota as a separate phylum?
A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data. Mycologia,108(5), 2016, pp. 1028–1046. DOI: 10.3852/16-042#
I want to study genetic diversity of Uropathogenic E. coli .I DNA extraction methods for E.coli by boiling.but i don't band in elektroforez.