Serratia Marcescens Under The Microscope🔬

Ever wondered what that pink slimy thing is in your bathroom? I noticed it in the past at one stage in Soju's water fountain. I also see it sometimes around the tap base on the vanity or shower. Even the new toilet bowl when we installed a new toilet. When I first noticed this I was determined to figure out why. I learnt it is a bacteria that is airborne and can survive in water. It loves damp and soapy areas and can easily spread, but it is not harmful. To get rid of them you just have to clean and scrub. I would scrub and use a steamer to get rid of them, but they have recently come back and I have been too lazy to get the steamer out again. But I did scrub today.

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Upon thinking of things to look under the microscope, I thought I might try looking at this pink slime to see what it looks like. I do hope we can see something interesting without having to stain it first. Let us find out.

Just as I thought, we can only see the bacteria when we close the iris diaphragm. Here you can see them moving. It is a little hard to see here, but this bacterium is rod shaped (bacilli).

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Considering this is just a temporary wet mount slide I created, I need to fix the coverslip before I can use the x100 lens to get a closer view of the bacteria. Here I let the wet mount slide dry a little before I seal the edges using a new clear nail polish I purchased which apparently dries in 60 seconds. Now I can use the immersion oil to use the 100x lens.

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Even at 1000x we cannot see the bacteria as easy. Maybe I should of tried using the x16 eyepiece to make it total 1600x magnification, but the image would not be clear still.

In order to see the bacteria better it requires to be fixed to the slide then stained using dye. Usually a Gram Stain is done using crystal violet & safranin dyes. This is a differential stain which helps to differentiate between the cell wall compositions of different types of bacteria. The bacteria could either be Gram Positive (violet colour) or Gram Negative (pink colour). Or a simple stain could be done just so you can see the shape better, such as crystal violet.

For those interested in understanding how Gram Stain is done, the bacteria are first fixed to the slide using heat/flame. It is then dyed with crystal violet dye then rinsed. Iodine (a mordant) is applied then rinsed. This will trap the violet colour depending on the cell wall composition. Alcohol is then applied to perform decolourisation. Those that do not retain the crystal violet dye will lose this colour during this process. A counter stain is completed using safranin dye then rinsed. This dyes the decolourised cells pink.

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I tried to go through my old school photos to see if I had taken a picture of any bacteria I had seen under the microscope. Unfortunately I could not find any. I am sure they are somewhere, or maybe I didn't take any photos of them.