In this article, we are going to discuss the different types of bacteria and provide a list of examples for each. The three main types of bacteria shapes are called coccus, bacillus, and spiral.
The word bacteria is the plural form of bacterium which are microscopic one-celled organisms that live on almost every surface.
They cannot be seen and can be harmful in the case of bacterial infections, but also helpful when it comes to fermentation and decomposition.
Although a lot of bacteria can be harmful to humans, animals, and the surrounding world, some are quite useful. In this article, we will give examples of both the good and the bad that exist.
The bad can cause diseases and infections that can be extremely harmful to live organisms, with some bacteria acting as viruses – meaning that they can only survive when attached to living things.
There are good bacteria though, like bacteria found in the gut that means that you are fit and healthy!
So, if you want to know more about the different types of bacteria there are, then carry on reading.
Definition Of Bacteria
A bacteria is a group of unicellular microorganisms. They have cell walls but lack organelles and an organized nucleus. Some bacteria can cause disease.
Bacteria have a very simple cell structure when compared to other organisms. Their center of control is contained in a single loop of DNA, which contains all of the genetic information.
Additionally, bacteria have an extra circle of genetic material called a plasmid.
They have this rather than a nucleus and it often constraints genes that give the bacterium advantages over other organisms.
Types Of Bacteria
As we mentioned earlier, there are three main shapes of bacteria. These include spherical, rod-like, and spiral shapes. The names for this are coccus, bacillus, and spiral.
Although it seems we only talk of bacteria as a bad thing in the world, for example when it comes to diseases and infection, they can actually be quite beneficial to us as well.
Let us take a look at each different shape of bacteria and discuss their qualities and provide a list of examples.
Sphere-Shaped Bacteria
The first type of bacteria we are going to talk about is bacteria that are sphere-shaped. These bacteria are called coccus, or cocci.
They are either sphere or oval in shape and grow in clusters or chains. Coccus bacteria can cause harm to humans, including bacterial infections such as strep throat (streptococcus pyogenes).
There are also other shapes of bacteria including comma and corkscrew, but we will only be mentioning the three main forms of bacteria today.
Although there are coccus bacteria that are harmful to humans, as we mentioned above, there are some that can be useful to us.
An example of this is the bacteria that make up human skin flora – staphylococcus epidermidis.
Coccus bacteria appear as single cells (coccus), pairs (diplococci), chains (streptococci), clusters of four (tetrads), irregular clusters (staphylococci), and large cuboid clusters (sarcinae).
Below is a list of examples of cocci (sphere-shaped) bacteria:
- Aerococcus Urinae – this type of bacteria causes urinary tract infections and urosepsis.
- Chlamydia Trachomatis – the bacteria that causes the sexually transmitted disease called chlamydia.
- Enterococcus Faecalis – this bacteria causes tooth and intestinal infections.
- Fusobacterium Necrophorum – this bacteria causes Lemierre’s syndrome.
- Fusobacterium Nucleatum – the bacteria that is the cause of periodontal disease.
- Moraxella Catarrhalis – this bacteria causes infections in the eyes, nervous system, and joints.
- Neisseria Gonorrhoeae – the bacteria that causes the sexually transmitted disease known as gonorrhea.
- Neisseria Meningitidis – bacteria causing meningococcal disease.
- Pediococcus acidilactici – this is a helpful gut disease.
- Pediococcus Damnosus – the bacteria that is found in fermented beverages and spoiled food.
Rod-Shaped Bacteria
Rod-shaped bacteria are called bacillus which is the Latin word for ‘’stick’’. This type of bacteria is found primarily in soil and water.
The cell shape of the bacillus is rod-like and can be identified by arrangement, similar to how cocci can be. These arrangements are single cells (bacillus), pairs (diplobacilli), and chains (streptobacilli).
You can also get oval-shaped bacilli which are called coccobacilli. The most common and well-known example of rod-shaped bacteria is E.coli – Escherichia Coli.
Below are some more examples of bacillus bacteria:
- Aeromonas Hydrophila – this is the bacteria that cause traveler’s diarrhea.
- Arcanobacterium Bemolyticum – this bacteria causes pharyngitis and sinusitis.
- Bacillus Anthracis – this bacteria causes anthrax and can be spread from animals to humans.
- Bordetella Pertussis – this bacteria causes whooping cough.
- Capnocytophaga canimorsus – this type of bacteria can cause infections in humans and is transmitted from cats and dogs.
- Chlamydophila Pnuemoniae – this type of bacteria is what causes bacterial pneumonia.
- Chlamydophila psittaci – this bacteria causes psittacosis and pneumonia in humans who’ve been exposed to infected birds.
- Citrobacter freundii – this bacteria is found in healthy intestinal systems, but is also known to cause serious infections when contaminated in other areas of the body.
- Clostridium Botulinum – this bacteria causes botulism.
- Clostridium Difficile – this is the bacteria that causes severe diarrhea and colitis.
- Clostridium Tetani – the bacteria that causes tetanus.
Although a lot of rod-shaped bacteria can make humans very ill, some types can actually help to ripen food. This bacteria include the following:
- Acetobacter Aceti – this bacteria converts ethanol to acetic acid and works in sugar fermentation.
- Bifidobacterium Adolescentis – this is the healthy gut bacteria that are found in babies.
- Gluconobacter oxydans – this bacteria causes rot in both fruit and vegetables.
- Hafnia Alvei – this bacteria is used as a probiotic in dairy supplement products.
- Pseudomonas Fluorescens – the bacteria that cause milk to spoil and coagulate.
The genus Rickettsia is also made up of primarily rod-shaped bacteria. Some can be spherical though, like cocci. This type of bacteria can be transmitted by regional parasites such as lice, ticks, or fleas.
They are unable to live outside of living cells, the same way that viruses behave.
Examples of Rickettsia bacteria include the following:
- Rickettsia Akari – bacteria transmitted by mites and causes rickettsialpox.
- Rickettsia Conorii – bacteria transmitted by ticks that causes spotted fever and tick typhus.
- Rickettsia Felis – bacteria transmitted by fleas that causes spotted fever.
Spiral-Shaped Bacteria
Bacteria that are shaped like spirals are found primarily in standing water. They would usually appear in two forms which are long, rigid spirals (spirilla) and thin, flexible spirals called spirochetes.
This bacteria can be carried by ticks, like Rickettsia bacteria.
Some examples of spiral-shaped bacteria include the following:
- Borrelia Afzelii – the bacteria that causes Lyme disease.
- Borrelia Hermsii – bacteria that cause relapsing fever.
- Campylobacter Coli – the bacteria that causes campylobacteriosis and foodborne illness.
- Helicobacter hepaticus – bacteria found in cases of hepatitis and colorectal cancer.
- Helicobacter Pylori – bacteria that causes stomach ulcers.
- Leptospira Interrogans – the bacteria that causes leptospirosis and Weil’s syndrome.
- Spirillum Minus – bacteria that is believed to cause rat-bite fever.
- Spirillum Volutans – bacteria found in freshwater.
- Treponema Pallidum – bacteria that causes syphilis
- Treponema Carateum – bacteria that causes an African skin disease called pinta.
Mycoplasma Bacteria
Sometimes it can be difficult to identify whether bacteria are spherical, rod-shaped, or spiral because they lack cell walls. These bacteria are referred to as Mycoplasma.
This bacteria is resistant to a lot of antibiotics because they do not have cell walls. They are also the smallest form of bacterial cells that exist.
Some examples of mycoplasma bacteria include the following:
- Mycoplasma Fermentans – the bacteria that cause respiratory and rheumatoid diseases.
- Mycoplasma Gallisepticum – the bacteria that causes chronic respiratory disease in animals and humans, but primarily in birds.
- Mycoplasma Hominis – the bacteria that causes bacterial vaginosis.
- Mycoplasma Genitalium – this bacteria is the cause of urethritis and pelvic inflammatory diseases.
- Mycoplasma Haemofelis – this bacteria causes blood infections in cats.
- Mycoplasma Incognitus – this is the bacteria that breaks down the immune system and can be the cause of both HIV and Parkinson’s disease.
- Mycoplasma Salivarium – the bacteria that is found in healthy mouths and oral flora.
Final Thoughts
So, this article has introduced you to the many different types of bacteria that exist in our world. We have included some examples that hopefully, you find useful and you now know more about bacteria and how they live.
Bacteria are not always a bad thing and can sometimes positively impact us and our surroundings, but they can also be the cause of bacterial infections and diseases that can be very harmful to both humans and animals.
Luckily, there are ways to protect yourself and your surroundings from any harmful bacteria by using anti-bac cleaning products to kill the germs before they can affect you.
There are also other ways you can kill these germs and prevent them from spreading, for example by washing your hands.
There are bacteria all over the world, and just because you cannot see it doesn’t mean it isn’t there.
The three main shapes of bacteria are listed in the above article alongside some of the most prevalent examples.
Hopefully, this has been a useful and insightful article for you and you know now, a lot more about the hidden world of bacteria.
Ever since I was a little girl, I have been fascinated by science. Every holiday I would ask for the newest science kit, and spend weeks learning with it.
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