Skip to main content

Blood Agar (BAP)

By

Blood Agar (BAP)


Blood Agar (BA) are enriched medium used to culture those bacteria or microbes that do not grow easily. Such bacteria are called “fastidious” as they demand a special, enriched nutritional environment as compared to the routine bacteria. 
Composition of Nutrient Agar
  • 0.5% Peptone
  • 0.3% beef extract/yeast extract
  • 1.5% agar
  • 0.5% NaCl
  • Distilled water
 Blood Agar is made from Nutrient Agar more:
  • 5% Sheep Blood
  • pH should be from 7.2 to 7.6 (7.4)
Preparation of Blood Agar
1.    Suspend 28 g of nutrient agar powder in 1 litre of distilled water.
2.    Heat this mixture while stirring to fully dissolve all components.
3.    Autoclave the dissolved mixture at 121 degrees Celsius for 15 minutes.
4.    Once the nutrient agar has been autoclaved, allow it to cool but not solidify.
5.    When the agar has cooled to 45-50 °C, Add 5% (vol/vol) sterile defibrinated blood that has been warmed to room temperature and mix gently but well.
6.    Avoid Air bubbles.
7.    Dispense into sterile plates while liquid.
Prepare culture

The specimen streaking on Blood Agar (BAP) agar.Incubation 37c 18-24h and CO2  5-10%.

Image result for mannitol salt agar strin

Uses of Blood Agar

Blood Agar is used to grow a wide range of pathogens particularly those that are more difficult to grow such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria species. It is also required to detect and differentiate haemolytic bacteria, especially Streptococcus species. It is also a differential media in allowing the detection of hemolysis  by cytolytic toxins secreted by some bacteria, such as certain strains of Bacillus, Streptococcus, Enterococcus, Staphylococcus, and Aerococcus. 

Blood agar can be made selective for certain pathogens by the addition of antibiotics, chemicals or dyes. Examples includes crystal violet blood agar to select Streptococcus pyogens from throat swabs, and kanamycin or neomycin blood agar to select anaerobes from pus.

1.    Blood Agar is a general purpose enriched medium often used to grow fastidious organisms
2.    To differentiate bacteria based on their hemolytic properties (β-hemolysis, α-hemolysis and γ-hemolysis (or non-hemolytic).


Hemolytic Blood Agar
Alpha hemolysis (α-hemolysis): Streptococcus pneumoniae ,Streptococcus viridans .etc.
Beta hemolysis (β-hemolysis): Streptococcus dysgalactiae,Group A streptococcus, Clostridium perfringens,  Listeria monocytogenes.etc.
gamma hemolysis (γ-hemolysis or non hemolysis) : Enterococcus faecalis, Staphylococcus saprophyticus,  Staphylococcus epidermidis.etc.

Referance: 
https://www.time2026end.com/

Labels:

Comments

Post a Comment

Popular posts from this blog

Mueller Hinton Agar

By
Mueller Hinton Agar (MHA)       The major use of Mueller Hinton Agar is for antimicrobial susceptibility testing. Composition of MHA Ingredients   Beef Extract                                  2.00 gm Acid Hydrolysate of Casein         17.50 gm Starch                                           1.50 gm Agar                                             17.00 gm Distilled Water                             1000 ml Final pH 7.3 ± 0.1 at 25ºC Why Mueller Hinton agar is used for antibiotic susceptibility testing? 1.     It is a non-selective, non-differential medium. This means that almost all organisms plated on here will grow. 2.     It contains starch. Starch is known to absorb toxins released from bacteria, so that they cannot interfere with the  antibiotics . It also mediates the rate of diffusion of the antibiotics through the agar. 3.     It is a loose agar. This allows for better diffusion of the antibiotics than most other plates. A bette
Post a Comment
Read more

Urease Test

By
Urease Test The urease test is used to determine the ability of an organism to split urea, through the production of the enzyme urease. Principle  Urea  is the product of decarboxylation of  amino acids . Hydrolysis of  urea  produces  ammonia  and  CO2 . The formation of  ammonia  alkalinizes the medium, and the pH shift is detected by the color change of  phenol red  from  light orange  at pH 6.8 to  magenta (pink)  at pH 8.1. Rapid urease-positive organisms turn the entire medium  pink  within 24 hours. Weakly positive organisms may take several days, and negative organisms produce  no color change  or  yellow  as a result of  acid production . Uses  1.     This test is used to differentiate organisms based on their ability to hydrolyze urea with the enzyme urease. 2.     This test can be used as part of the identification of several genera and species of Enterobacteriaceae, including  Proteus, Klebsiella ,
Post a Comment
Read more

INTRODUCTION TO MYCOLOGY

By ok learning
MYCOLOGY INTRODUCTION TO MYCOLOGY Contents 1 Objective 2 Meaning 3 Growth 4 General structures FUNGI: 1 Purpose · Types of colors and definitions · Separation of yeast and mold 2.Definition Mycology is a fossil science study. Mycosis is a fungal infection. Yeast is a large cell, with only one type of cells, most of which are non-transplantation, called budding. Mold is a multicellular cell. Most of the fertilized egg is enlarged. 3 Growth a.Yeast: routine incubation temperature is usually 25c b. Mold: routine incubation temperature is usually 25c o to 30c o , although 35c o incubation can be used to differentiate some mold based on temperature tolerance or determine whether organisms are diphasic. c. Diphasic (dimorphic fungi): These organisms differ in two forms depending on temperature. d. Frequently used media The most common use of: - spermatozoa-Sabouraud's dextrose agar (SDA) - Sabouraud's dextrose agar
Post a Comment
Read more