Haemolysis Of Streptococci And Its Types With Examples

The field of science that surrounds the study of the human body is as complex as the life form it is trying to understand.

Whether you’re a researcher or even just an amateur science enthusiast, there are so many specific fields of biology, chemistry, and microbiology that experts and academics can spend their entire lives researching a single topic in a single field, and still have an endless ocean of knowledge to continue exploring.

Still, that doesn’t mean that great headway hasn’t been made in understanding how our biological machines function and operate. Far from it. We now know more about humans than we have ever known.

And understanding that can even be a headache for a newbie looking into research on human biology.

Haemolysis Of Streptococci And Its Types With Examples

Take, for example, our knowledge of how blood and red blood cells break down in our bodies. Also known as Hemolysis.

Just this single field has given us an incredible amount of information to piece together and learn about, especially the many other types of microorganisms that we have come to learn are linked to this simple, yet vital bodily function.

It certainly makes learning more of a hassle!

Well, hassle no more, because we have compiled all the information you’ll need to get to grips with the basics of this particular subject.

We’re going to cover the basics of hemolysis, as well as several types of bacteria from the genus Streptococcus, what distinguishes them from each other, as well as a few examples of each type.

A Brief Introduction To Haemolysis

Before we begin discussing how Streptococcus bacteria affect the process of hemolysis, we’ll briefly cover what exactly hemolysis is first.

As we mentioned briefly in the introduction, hemolysis is effectively the process of when red blood cells break down inside the body. Red blood cells provide a vital service to the body, delivering oxygen around the body.

Substances that can start this process, both with negative and positive consequences and in both the human body, as well as in microbiological studies, are known as hemolysin and were first identified in the early 20th century. 

Many hemolysins can be found in the family of bacteria that we are about to discuss: Streptococcus.

What Are Streptococci?

The Genus Streptococcus covers a wide array of many different species of spherical bacteria, whose purposes and properties vary wildly depending on the species.

The most famous examples of this genus are widely known pathogens, being the causes of many familiar illnesses ranging from relatively harmless or treatable conditions such as Strep Throat to more serious bacterial infections such as pink eye or meningitis, which can cause dangerous amounts of inflammation without the proper treatment.

However, Streptococci are a massive collection of different species, many of which are completely harmless. Many species of Streptococci are vital to the process of hemolysis.

Many species are classified by the exact hemolytic properties that they have on red blood cells.

These classifications were first introduced in 1919, based on their reactions to hemolytic cultures in blood agar tests, and are broadly separated into three groups: Alpha, Beta, and gamma.

Types Of Streptococci

Types Of Streptococci


Alpha-hemolytic is a hemolytic agent that, when tested and placed in a blood agar medium plate, will turn the solution or medium a faint green color across where the bacteria culture has been placed and exposed to red blood cells.

The partial change in appearance and color signifies that this is a partial hemolytic agent.

This means that, although this bacteria has a transformative effect on the hemoglobin molecules within a red blood cell, the cell membrane is left largely intact.

Under a microscope, it is even possible to see that alpha-hemolytic form pairs or chains, helping to identify them when observed.

Some famous examples of this type of hemolytic include pneumococcus, (also known as Streptococcus pneumoniae), which is a leading cause of bacterial-caused pneumonia.


Beta-hemolytic bacteria can be considered a complete hemolytic agent, as this bacteria, when placed in a blood agar plate, will cause red blood cells to completely break down when they interact with this species of bacteria, leaving a very clear and colorless make in an agar try when this culture is applied.

It is inactive until it reacts to the oxygen-rich hemoglobin in a red blood cell, causing complete lysis to occur (total breakdown of the red blood cell, as we just mentioned).

This group of hemolytic includes some well-known species of Streptococcus, including S. pharyngitis, strep throat or tonsillitis, as well as rheumatic fever.


This group of bacteria is considered non-hemolytic by scientists and researchers.

When a culture of bacteria from this classification is applied to an agar plate prepared for testing, there is very little to no reaction from red blood cells.

At most, slight browning of the agar plate might be observed, as the blood interacts with the laboratory conditions it is in an increase in carbon dioxide, for example).

There are very few if any pathogens in this group. Some examples of this group would include bacteria such as Enterococcus faecalis.

Final Thoughts

As you can see, observing hemolysis can be a vital area of study for finding bacterial infections in the human body. Hopefully, now, you also understand the human body a little better.

Jennifer Dawkins