Biochemical Test of Streptococcus pneumoniae

Biochemical Test of Streptococcus pneumoniae

Biochemical tests for Streptococcus pneumoniae are laboratory procedures developed to analyze certain biochemical features of this bacterium, assisting in its identification and distinction from other microbes.

What is Streptococcus pneumoniae?

This often known as pneumococcus, is a Gram-positive bacterium commonly seen in the upper respiratory tract of humans. It is a major human pathogen responsible for a variety of illnesses, including pneumonia, meningitis, otitis media (middle ear infection), sinusitis, and bacteremia.

Biochemical Test of Streptococcus pneumoniae

S. pneumoniae causes a significant burden of morbidity and mortality worldwide, especially among young children, the elderly, and people with weaker immune systems. It is a significant cause of bacterial pneumonia, particularly in children under the age of five and those over the age of 65.

Biochemical Test of Streptococcus pneumoniae

1. Catalase Test

Catalase Test

Purpose:

The catalase test identifies the presence of the enzyme catalase, which converts hydrogen peroxide to water and oxygen. It is catalase-negative, which means it doesn’t make it.

Procedure:

A little amount of bacterial colonies is combined with hydrogen peroxide. If bubbles (oxygen generation) are detected, the catalase test is positive.

Result:

The outcome is negative. Streptococcus pneumoniae does not create bubbles, implying a lack of catalase function.

2. Optochin Sensitivity Test

Optochin Sensitivity Test

Purpose:

The optochin sensitivity test distinguishes Streptococcus pneumoniae from other alpha-hemolytic streptococci. S. pneumoniae is sensitive to optochin.

Procedure:

A disk impregnated with optochin (ethylhydrocupreine hydrochloride) is placed on a growth plate containing the bacteria. After incubation, the zone of inhibition surrounding the disk is assessed.

Result:

Positive. It shows a clear zone of inhibition (≥14 mm) around the optochin disk

3. Bile Solubility Test

Purpose:

The bile solubility test measures bacteria’s ability to lyse in the presence of bile salts. It is biliary soluble.

Procedure:

A bacterial colony is suspended in a bile salt solution. Following incubation, the presence of a clear zone around the colony shows bile solubility.

Result:

Positive. its lyses and forms a clear zone surrounding the colony in the presence of bile salts.

4. Hemolysis on Blood Agar

Purpose:

The hemolysis test determines the type of hemolysis (partial or total) caused by bacteria on blood agar plates. It generally exhibits alpha-hemolysis.

Procedure:

Bacterial colonies are streaked onto blood agar plates and then incubated. Alpha-hemolysis is characterized by a greenish tint surrounding the colonies caused by partial hemolysis of red blood cells.

Result:

The result is alpha-hemolysis. It exhibits partial hemolysis, which causes a greenish coloring around colonies.

Other tests:

5. Bile Esculin Test

When Streptococcus pneumoniae encounters bile, it hydrolyzes esculin, causing the medium to turn black.

6. Pyruvate Broth Test

S. pneumoniae ferments pyruvate, generating acid and changing the colour of the medium.

7. Inulin Fermentation Test

Streptococcus pneumoniae ferments inulin, which produces acid and changes the color of the medium.

8. Sugar Fermentation Tests

Streptococcus pneumoniae commonly ferments glucose, with mixed findings for lactose and sucrose fermentation.

When conducted collectively, these biochemical assays provide useful information for accurately identifying and distinguishing Streptococcus pneumoniae from other bacteria.

Frequently Asked Question(FAQ)

What is Streptococcus pneumoniae?

Streptococcus pneumoniae, often known as pneumococcus, is a Gram-positive bacterium commonly seen in the upper respiratory tract of humans. It is a major human pathogen responsible for a variety of illnesses, including pneumonia, meningitis, otitis media (middle ear infection), sinusitis, and bacteremia.

What are the Biochemical Test of Streptococcus pneumoniae?

The Biochemical Test of Streptococcus pneumoniae are:
1. Catalase Test
2. Optochin Sensitivity Test
3. Bile Solubility Test:
4. Hemolysis on Blood Agar
5. Bile Esculin Test
6. Pyruvate Broth Test

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