General Purpose media is designed to grow most organisms and do not contain growth inhibitors. Standard Methods Agar and Blood Agar Bases are examples of general purpose media.
Category: Chemicals & Stains
This is a special type of medium that is used to grow microorganisms that are damaged and have lost the ability to produce due to certain harmful environmental factors.
Differential media are bacteriological growth media that contain specific ingredients that allow to distinguish selected species or categories of bacteria by visual observation. Differential means are used to distinguish between organisms or groups of closely related organisms. Examples of differential media : Mannitol salts agar (mannitol fermentation = yellow) Blood agar (various kinds of hemolysis i.e. α, β and γ hemolysis) Mac Conkey agar (lactose fermenters, pink colonies whereas non- lactose fermenter produces pale or […]
It is used as diluting fluid for blood specimens to count red blood cells under high powder. Composition: Ingredients: Mercuric chloride – 0.25 gm Sodium sulphate – 2.50 gm Sodium chloride – 0.50 gm Distilled water – 100.0ml Final pH ( at 25°C) – 5.9±0.1 RBC Test Procedure Principle And Interpretation: RBC diluting fluid is isotonic with blood, hence hemolysis does not take place. Normal Saline also can be used. But it causes slight creation […]
Endospores are dormant forms of living bacteria and should not be confused with reproductive spores produced by fungi. These structures are produced by a few genera of Gram-positive bacteria, almost all bacilli, in response to adverse environmental conditions. Two common bacteria that produce endospores are Bacillus or Clostridum. Both live primarily in soil and as symbionts of plants and animals, and produce endospores to survive in an environment that change rapidly and often. Endospore stain procedural steps. Step […]
Some bacteria produce the waxy substance mycolic acid when they construct their cell walls. Mycolic acid acts as a barrier, protecting the cells from dehydrating, as well as from phagocytosis by immune system cells in a host. This waxy barrier also prevents stains from penetrating the cell, which is why the Gram stain does not work with mycobacteria such as Mycobacterium, which are pathogens of humans and animals. For these bacteria, the acid–fast staining technique […]
The Ziehl-Neelsen (ZN) method of the Acid Fast staining technique is used to stain Mycobacterium species, including M. tuberculosis, M. ulcerans and M. leprae, and non-tuberculous mycobacteria (NTM). Detection of acid-fast bacilli (ARB) in microscopically examined acid-washed and stained smears can provide initial bacteriological evidence for the presence of mycobacteria in a clinical specimen. Smear microscopy is the fastest and easiest procedure that can be performed. The cell wall of mycobacteria contains a high concentration […]
Gram staining is initially established by the physician Hans Christian Gram, which was from Denmark. He help to distinguish Klebsiella pneumonia to pneumococci.
Binding of specific cell or tissue structures (usually proteins) by an antibody directed against that protein. This antibody is often raised in a species other than the one from which the specimen is taken. For example, antibodies may be developed in rabbits to a protein present in human tissue. There are several methods for visualizing where these antibodies have bound to the tissue. In the example above, other antibodies directed against rabbit proteins that are […]