STREPTOCOCCUS

STREPTOCOCCUS411 , Lab 5

Amany Niazy

StreptococciAll are Gram Positive Cocci arranged in chains (short or long)

All are Catalase -ve

+ ve- veGram StainStaphylococcistreptococci

CultureFastidious organism no growth on NA

Grows well on BAP

Facultative anaerobe

Grow at 37C need 24 to 48 hour .Streptococcus ClassificationAlpha hemolyticS. viridansS. pneumoniaeBeta hemolytic:Group A, B, C, G & DLancefield grouping according to antigens in their cell wall Non-hemolytic:Enterococcus (formaly known as Group DAlpha Hemolytic StreptococciGive alpha hemolysis on BAP.

It Can be divided in to 2: Viridans group

S.pneumoniae

Streptococcus viridanss. pneumoniae

S. PNEUMONIAEViridans StreptococciAlpha haemolysis

Pin point colonies

Optochin resistant

Bile Solubility -ve

Part of normal flora of upper respiratory and GIAlpha haemolysis

Ring form colonies

Tanslucent or mucoid

Optochin sensitive

Sile solubility +ve

Not part of NFCapsulatedNot CapsulatedFlattened with raised edgesViridans StreptococciS. PNEUMONIAE

GPS in chains

GPC elongated (Lanceolated) diplococci

1. Optochin TestEthylhydrocupreine hydrochloride.

Zone of inhibition of 14 mm or more sensitive S. pneumoniae

No zone of inhibition S.viridans

Always don on a BAP.On the primary culture of isolation plate before incubationOptochin Disk

. Bile Solubility TestTo test if colonies are lysed by bile salt (such as desoxycholate) or not.

There are 2 ways to do the test :

In a tubeOn plate

Bile Solubility in Tube2 ml of saline in a tubeEmulsify several colonies of test organism in itDivide organism suspension in 2 tubesAdd 2 drops of bile salt to one tube and 2 drops of sterile distilled water to the other.Leave 10-25 mn at RT

Bile Solubility on PlateAdd drop of bile salt to specified part of plateIncubate at 37C for 10 - 30 minColony disappear +veColony stay -ve

Rapid Detection of S. pneumoniaeRapid latex and coagglutination tests are available to detect capsular pneumococcal antigen in CSF or other sterile body fluids.

Sensitivity Testing of S. pneumoniae

18Thank You