Alpha Hemolysis vs. Beta Hemolysis

Main Difference

The main difference between Alpha Hemolysis and Beta Hemolysis is that Alpha Hemolysis is associated with partial hemolysis and related to the reduction of hemoglobin levels in red blood cells, whereas Beta Hemolysis is associated with the complete hemolysis of red blood cells that usually present around the colony.

Difference Between Alpha Hemolysis and Beta Hemolysis

Comparison Chart

Alpha Hemolysis vs. Beta Hemolysis

Alpha hemolysis usually states about the partial hemolysis of red blood cells and greenish staining, immediately surround the colonies some streptococci present on the blood agar plates; on the other hand, beta hemolysis states about the complete breakdown of red blood cells illustrated by the perfect zone which usually surrounds the colony of bacteria present in the blood agar plates.

Partial hemolysis or green hemolysis are some other names of alpha hemolysis; on the contrary, complete hemolysis is also known as beta hemolysis. Alpha hemolysis is referred to as the type which is the partial hemolysis of red blood cells; on the flip side, beta hemolysis is referred to as the type which is the complete hemolysis of red blood cells.

Alpha hemolysis is generally caused by the hydrogen peroxide, which is formed by the bacterium, whereas beta hemolysis is normally caused by the by-products of toxic substances that always destroy the red blood cells. In the process of alpha hemolysis, the hydrogen peroxide dissolves hemoglobin (red) into methemoglobin (green), while beta hemolysis, beta hemolysis, completely ruptures all the red blood cells.

In alpha hemolysis, the red blood cells remain intact; on the other hand, in beta hemolysis, the red blood cells are broken down. Alpha hemolysis forms greenish-black regions; on the other hand, beta hemolysis forms clear and perfect zones.

The width of the zone in alpha hemolysis is 1-2 mm; on the contrary, the width of the zone in beta hemolysis is 2-4 mm. Some types of streptococcus of alpha hemolysis are Streptococcus pneumonia and Streptococcus viridian’s, whereas only Streptococcus pyogenes go through into beta hemolysis. The species which undergo alpha hemolysis are located in the oral cavity, while the species which undergo beta hemolysis are located in the throat.

What is Alpha Hemolysis?

Alpha hemolysis is known as the partial hemolysis of red blood cells forming the greenish discoloration, which is present around the bacterial colony in the blood agar plates. Alpha hemolysis is also known as the partial hemolysis or green hemolysis.

Alpha hemolysis is caused by several Streptococcus species such as Streptococcus pneumonia, Streptococcus mitis, Streptococcus mutans, Streptococcus salivarius, and Streptococcus viridians. Alpha hemolysis is considered as the type of partial hemolysis in which the iron molecules present in the hemoglobin are dissolved by hydrogen peroxide, which is produced by the bacterium.

The partial hemolysis gives greenish color to the surrounding of the colony of the bacteria because hemoglobin (red) is converted into methemoglobin (green). Alpha hemolysis is the incomplete break down of the red blood cells, and these red blood cells remain intact during the contagion in the body.

The process of alpha hemolysis is usually catalyzed by the hemolytic bacterial enzyme known as alpha-hemolysin. The prolonged incubation in alpha hemolysis allows the formation of clear areas. Alpha hemolysis is used as an indicative feature during the credentials of the bacterial strain. The species which undergo alpha hemolysis are located in the oral cavity.

What is Beta Hemolysis?

Beta hemolysis is known as the complete breakdown and destruction of red blood cells. Beta hemolysis is also known as the complete hemolysis. Beta hemolysis forms a clear area around the bacterial colony in the blood agar plate.

Beta hemolysis always involved in the red blood cell’s true or complete hemolysis. The complete breakdown of red blood cells is caused by the by-products of toxic substances.

The hemolysin Streptolysin O is produced by the Streptococcus pyogenes, and it is only active in the low oxygen conditions. On the agar plate, the anaerobic compartments are produced by piercing an injecting ring vertically into the agar, after flashing the plate.

The oxygen-stable hemolysin Streptolysin S is produced by some Streptococcus pyogenes. Some reactions of beta hemolysis are considered very delicate, and some of these weak hemolysis reactions produce in Streptococcus agalactiae or Listeria monocytogenes.

The bacterial hemolytic enzymes destroyed the cell membranes of the red blood cells. Hence, molecules of hemoglobin released into the blood plasma of the body. The bacterial enzyme known as beta-hemolysin is the cause of the occurrence of beta hemolysis and that bacteria are known as beta-hemolytic bacteria.

The species which undergo beta hemolysis are located in the throat. As beta hemolysis completely breakdown the red blood cells, so clear zones are started to visible around the bacterial colonies.

Conclusion

The above discussion concludes that both types of hemolysis alpha and beta occur by the infection of the different Streptococcus species, and both are having differences. Alpha hemolysis is a form of partial hemolysis and forms zones of green color, whereas beta hemolysis is a type of complete hemolysis and forms clear zones.