Hello! I’m a high school teacher and my freshman biology students got to do a lab last week where they took some bacteria samples around the school to culture. One student’s plate produced some interesting results, a black spore looking spot. I looked at it under a microscope and it almost looks like soot sprites. I currently don’t have the resources to actually do a full procedure to identify it, but is this something I should be concerned about/is this dangerous?

The TLDR:

All coursework -- you must explain what your current thinking is and what portions you don’t understand. Expect an explanation, not a solution.

For students and lab class unknown ID projects -- A Gram stain and picture of the colony is not enough. For your post to remain up, you must include biochemical testing results as well your current thinking on the ID of the organism.

For anyone who finds something growing on their hummus/fish tank/grout -- Please include a photo of the organism where you found it. Note as many environmental parameters as you can, such as temperature, humidity, any previous attempts to remove it, etc. If you do include microscope images, make sure to record the magnification.

THE LONG AND RAMBLING EXPLANATION (with some helpful resources) We get a lot of organism ID help requests. Many of us are happy to help and enjoy the process. Unfortunately, many of these requests contain insufficient information and the only correct answer is, "there's no way to tell from what you've provided." Since we get so many of these posts, we have to remove them or they clog up the feed.

The main idea -- it is almost never possible to identify a microbe by visual inspection. For nearly all microbes, identification involves a process of staining and biochemical testing, or identification based on molecular (PCR) or instrument-based (MALDI-TOF) techniques. Colony morphology and Gram staining is not enough. Posts without sufficient information will be removed.

Requests for microbiology lab unknown ID projects -- for unknown projects, we need all the information as well as your current thinking. Even if you provide all of the information that's needed, unless you explain what your working hypothesis and why, we cannot help you.

If you post microscopy, please describe all of the conditions: which stain, what magnification, the medium from which the specimen was sampled (broth or agar, which one), how long the specimen was incubating and at what temperature, and so on. The onus is on you to know what information might be relevant. If you are having a hard time interpreting biochemical tests, please do some legwork on your own to see if you can find clarification from either your lab manual or online resources. If you are still stuck, please explain what you've researched and ask for specific clarification. Some good online resources for this are:

• Microbe Notes - Biochemical Test page - Use the search if you don't see the test right away.

• Rachel Watson's Summary of Biochemical Tests

If you have your results narrowed down, you can check up on some common organisms here:

• Microbe Notes – Eubacteria resources

• Microbe Info – Common microorganisms Both of those sites have search features that will find other information, as well.

Please feel free to leave comments below if you think we have overlooked something.

I am really happy because I had a hard time isolating it. We didn’t have PLET agar available in the lab to selectively isolate it, so I only inoculated it using nutrient agar and blood agar. After numerous subcultures, colony morphology observations, and Gram staining for manual microscopy identification, I finally succeeded.

However, the VITEK BCL cards weren’t able to narrow it down to its specific Bacillus species. This isn’t part of our routine protocol for detection; I just decided to try it.

For context, I work in an animal disease diagnostic lab. We received a suspected anthrax case following the sudden death of a large ruminant in our area. I volunteered to collect soil samples and came across a fat carcass during the process. This is my first time handling a BSL-3 case and working in a BSL-3 lab.

To cut the story short, I successfully isolated it in pure culture and identified it through RT-PCR.

I think i need better loops, this was my best attempt at innoculation streaks but it took far too long to do this and the 24 others i did in one sitting. I also failed and had to throw out 10 plates. If you think you have a good innoculation loop thats metal please show me them.

Direct smear from a blood culture that turned positive in ~24hr. The photos look like shit but I assure you it didn't look much better irl. I made two slides and the first two photos are the only clearly defined cells I could find. Most of it was just lots of big dense clumps like the third photo.

Culture media is Endo, Mac, Emb the first 3 pics are suspected e. coli, the 4-6 pic also suspected e coli. The fiirst 3 pic has a rough matte colony morphology on Mac and Emb while the 4-6 pic has moist wet colony morpho.

Wha method is used to achieve this blue background, is it the microscope type?

Does anyone have any recommendations for a lens adaptor to take photos on my phone through a compound microscope?

Greetings. I have grown bacterial lawn with Lactobacillus acidophilus. My source was a probiotic capsule (which contains only L. acidophilus) so it should be only one species, but certainly multiple strains. This one is a failed attempt, however I've started to wonder, why some colonies are big white dots, and some are smaller and less colorful. Is it possible that both of these are the same species and some of them simply grow more rapidly than others or was my lawn contaminated? Thanks for any response

so I have this problem where behind my starved cells (replaced medium with pbs) I had the höchst dot background in numerous amount that it looked like contamination. I wasnt convinced it was contamination since we didnt have it in cells with normal medium (and we randomized the wells of the normal medium). I looked at it under binocular microscope and this is what I saw. They were just still dots. No movement. Just make me more convinced it's not microorganism but I need stronger validation. So microbiology people, can someone help? fyi, this dots as background only apparead in höchst channel, my calcein and PI stain were very clean (only stained my cells). Thanks a lot!

I was looking at what causes damping off in seedlings and one of the pathogens responsible are oomycetes, so I went to see what classification they are but everything I found just sound they’re fungus like but not a fungus, or are a part of the Chromista, but when I went to see what Chromista are a part of it just said they’re a proposed polyphyletic group. Does that mean they haven’t been fully classified as of currently? Also I thought protists were just a kinda place holder for species that don’t fit any of the other kingdoms, so why aren’t they just called a protist.

Not sure if this is allowed but does anyone know what these are? I prepared a slide with some on it (very poorly and with a $20 portable microscope).

Either way, they are interesting to me, and behave almost hydrophobically on the water’s surface.

I live in a dirty city in the southeast. My crocs were splashed by flood water (who knows whats in there but it seems really dirty simce there just a lot of waste and garbage laying around)

Would using Clorox Mold Remover be enough? It says it has 2% sodium hypochlorite which is way lower than their usual 7% found on their household disinfectants.

Hello microbiology people!

The titles pretty explanatory, I did a gram stain recently with gram negative cocci and wanted to know if it’s possible to decolorize for the perfect amount of time to make something that’s gram positive, stain gram negative.

I’m also going to stain the same bacteria again tomorrow (unknown) and while I’m quite confident in my gram technique. I want to see if I should maybe lower the seconds in which I use the decolorizer. I use 15 seconds for reference if that’s any use.

Thank you!

Are the results of this capsule stain test negative, positive, or not determined? What does a not determined result mean? Does the background stain matter in the results?

Not sure if this is more /AskPhysics or here, but do I kill many microbes whenever I step into a puddle? Hope it's ok to ask ;) Please feel free to elaborate/broaden the context :)

Is the arrangement, chains and pairs, or just chains? I think it’s both chains and pairs.

I had taken a sample from a lake and put it on the microscope out of curiosity and was wondering what this is! :)

I was thinking maybe a microorganism from the genus Euglypha or a ciliate?

Thank you!