There are over 30,000 formally named species of bacteria that have been discovered to date. Much like animals, these bacteria fall under the same umbrella category, but are not all the same – there are various types and categories. Each kind of bacteria is classified into a different grouping based on their shape.
The five shapes of bacteria are cocci, bacilli, spirilla, vibrios, and spirochaetes. Cocci and bacilli bacteria are shaped like a sphere and rod respectively. Spirilla and vibrios bacteria are shaped like a spiral and comma respectively, and finally, spirochaetes are shaped liked corkscrews. The shape of each bacteria gives them both advantages and disadvantages when it comes to survival.
Lyme disease is caused by a type of spirochaetes bacteria. But what is a spirochaete, exactly, and is Lyme bacteria gram positive or negative? Let’s find out.
What type of bacteria is Lyme disease?
As mentioned above, Lyme disease bacteria is a type of spirochaete, which means it is shaped like a corkscrew. The bacteria, which is named borrelia burgdorferi, belongs to a specific class of bacteria known as genus borrelia. While there are other bacteria that fall into the same category, they do not all cause the same health issues. For example, the bacteria that causes syphilis is considered to be a spirochaete, but it does not cause Lyme disease.

The spiral-shaped borrelia bacteria is considered to be a microaerophilic two-membrane bacterium, which means that it has two membranes that offer a sort of protection while allowing water and other important molecules through. The membrane is also thought to aid in how viral the bacteria is.
On top of its double membrane and spiral shape, the genome of the borrelia bacteria also contains more plasmids than any other bacteria. Plasmids are the genetic structure that help the bacteria to replicate.
What does gram negative mean in bacteria?
While bacteria are placed in different species and shape categories, they are also designative “gram negative” or “gram positive”. This is another measure scientific researchers can use to differentiate between the bacteria as a way to learn more about how they can infect humans and animals, as well as what good they might do for the body. Because there are both good and bad bacteria, understanding how they function is important.
The gram negative classification is used to identify how certain bacteria show up on something called a gram stain. This technique involves applying a violet-colored dye to the bacteria before decolorizing it and then repeating with a red dye.
What’s the difference between gram positive and negative bacteria?
A gram stain helps to decipher the difference between the structures of types of bacteria. When the cells that are given the violet dye appear red after the gram stain process is finished, they are considered to be gram negative because they do not hold the violet color. If the cells do hold the violet color, they are designated gram positive.
Gram negative bacteria have a layer of thin peptidoglycan (a substance that makes up the cells walls of bacteria). This cell wall is surrounded by an outer membrane that contains a large molecule known as lipopolysaccharide. In gram positive bacteria, this outer membrane is not present. Their structure is maintained only by the layers of peptidoglycan. However, the peptidoglycan in gram positive bacteria is much thicker than what is found on gram negative bacteria.
Simply put, gram negative and gram positive bacteria have different structures, and thus hold the violet dye in a different way after the staining process.
Is borrelia gram positive or negative?
While most bacteria can be split into either gram positive or gram negative categories, Lyme bacteria is a little different. While it is sometimes considered a gram negative bacteria because of its structure, it doesn’t entirely fall into either grouping. Due to this, the borrelia bacteria and others like it are referred to as atypical because during the staining process, they can remain completely colorless. With the absence of any color, researchers cannot give them a gram positive or negative rating.
This can be somewhat confusing, since the borrelia bacteria does contain a structure that scientific researchers would deem to be gram negative; however, it does not fall as neatly into that category as other bacteria.