Biochemical Tests for Streptococcus pyogenes | Bacteriology Notes

BIOCHEMICAL TESTS FOR STREPTOCOCCUS PYOGENES

There are so many biochemical reactions for the well known causative agent of Pyogenic infection i.e. the Streptococcus pyogenes but a few reactions are most commonly used and are medically important for distinguishing pathogenic strains of Streptococcus pyogenes from other non- pathogenic strains of S. pyogenes as well as from other species of Streptococcus which are as follows:



Beta hemolysis on Blood agar

Beta hemolysis and growth on PNF medium

Beta hemolysis and Growth on Crystal Violet Blood Agar (CVBA)

Catalase Negative

Insoluble in 10% Bile (differentiate S. pyogenes from S. pneumoniae)

PYR hydrolysis

pyr test - streptococcus pyr test - pyr test for streptococcus - streptococci pyr test
POSITIVE & NEGATIVE PYR TEST (STREPTOCOCCUS PYOGENES IS PYR POSITIVE)

Unable to ferment Ribose (differentiate S. pyogenes from other Streptococci)

Pyrase production

Sensitive to Bacitracin (differentiate S. pyogenes from other Hemolytic Streptococci)

Below is the list of various other biochemical tests for Streptococcus pyogenes which have great importance in research and for knowledge but are not routinely employed:





TESTSRESULTS
Coagulase-VE (NEGATIVE)
Catalase-VE (NEGATIVE)
Hyalurodinase+VE (POSITIVE)
Neuraminidase+VE (POSITIVE)
Acetoin production-VE (NEGATIVE)
Indole-VE (NEGATIVE)
MR (Methyl Red)+VE (POSITIVE)
VP (Voges Proskauer)-VE (NEGATIVE)
Alkaline Phosphatase+VE (POSITIVE)
PYR+VE (POSITIVE)
Urease-VE (NEGATIVE)
DNase+VE (POSITIVE)
Oxidase-VE (NEGATIVE)

Streptococcus pyogenes and other species of Streptococci ferment various sugars producing acid without gas.

But these sugar fermentation tests are of no diagnostic value in routine laboratory tests except Ribose fermentation test which is of great importance in differentiating Streptococcus pyogenes, which is Ribose Negative, from other Pathogenic & non-pathogenic Streptococci especially from Streptococcus equisimilis.

The other sugar fermentation tests which are described below are of great importance in research work.

SUGARSRESULTS
Fructose+VE (POSITIVE)
Galactose+VE (POSITIVE)
Glucose+VE (POSITIVE)
Lactose+VE (POSITIVE)
Maltose+VE (POSITIVE)
Sucrose+VE (POSITIVE)
Trehalose+VE (POSITIVE)
Arabitol-VE (NEGATIVE)
Arabinose-VE (NEGATIVE)
Dulcitol-VE (NEGATIVE)
Erythritol-VE (NEGATIVE)
Hippurate-VE (NEGATIVE)
Mannitol-VE (NEGATIVE)
Raffinose-VE (NEGATIVE)
Ribose-VE (NEGATIVE)
Sorbitol-VE (NEGATIVE)
Xylose-VE (NEGATIVE)
CellobioseVARIABLE (depends on strain)
GlycerolVARIABLE (depends on strain)
GlycogenVARIABLE (depends on strain)

That’s all about the Biochemical tests for Streptococcus pyogenes.




Further Reading:
Streptococcus pyogenes identification – Microbiology info
Streptococcus pyogenes Characteristics – Microbeonline
Image credit: Microbiology Notes

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