What is Congo red agar used for?

The CRA plate test uses a solid medium, namely Congo red agar. This method allows for the direct analysis of the colonies and the identification of slime-forming strains (which appear as black colonies on the red agar) and non-slime-forming strains (red-coloured colonies).

How to make Congo red agar?

The medium composed of Brain heart infusion broth (37 gm/l), sucrose (5 gm/l), agar number 1 (10 gm/l) and Congo red dye (0.8 gm/l). Congo red stain was prepared as concentrated aqueous solution and autoclaved at 1210C for 15 minutes. Then it was added to autoclaved Brain heart infusion agar with sucrose at 550C.

Can you test for biofilm?

There are various methods to detect biofilm production like Tissue Culture Plate (TCP), Tube method (TM), Congo Red Agar method (CRA), bioluminescent assay, piezoelectric sensors, and fluorescent microscopic examination.

How is biofilm formation measured?

Imaging and automated cell counting are the most common methods of biofilm quantification. Furthermore, the use of stains or fluorescent markers, in order to more accurately identify cells of interest and distinguish from culture debris, allow for easier and increased accuracy of cell counting and data interpretation.

What is Congo red dye?

Congo Red is the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid; a diazo dye that is red in alkaline solution and blue in acid solution and used especially as an indicator and as a biological stain. NCI Thesaurus (NCIt) Congo Red is an indicator dye that is blue-violet at pH 3.0 and red at pH 5.0.

How do you know if you have biofilms?

What are the signs that a biofilm has developed? The wound that has been infected with bacteria forming a biofilm may be much slower to heal or not heal at all, and may not improve with standard antibiotics. It may look sloughy or have an unpleasant smell.

What color is biofilm?

PCC 9104 subaerial biofilms. White, and a lesser extent red, surfaces stimulate biofilm biomass production. Red and white surfaces induce the highest production of biofilm pigments. Black and blue surfaces maximize oxidative stress and EPS production in biofilms.

What is biofilm growth?

Biofilm formation is a process whereby microorganisms irreversibly attach to and grow on a surface and produce extracellular polymers that facilitate attachment and matrix formation, resulting in an alteration in the phenotype of the organisms with respect to growth rate and gene transcription.

Is blood agar selective?

Blood Agar Is Not a Selective Medium If a bacterial growth medium is selective, that means that it grows only certain types of microbes while inhibiting the growth of other types of microbes. Blood agar is an enriched medium that provides an extra rich nutrient environment for microbes.

What grows MacConkey Agar?

Altogether, MacConkey agar only grows gram-negative bacteria, and those bacteria will appear differently based on their lactose fermenting ability as well as the rate of fermentation and the presence of a capsule or not.

How is the Congo red agar test used?

Investigation of staphylococcal biofilm can be carried out using various phenotypic methods. The Congo red agar (CRA) test developed by Freeman et al. (1989) is based on the subculture of the bacterial strains on brain heart infusion agar (BHIA), supplemented with sucrose and Congo red dye.

How to use Congo red dye for staphylococci?

Congo Red Method The medium composed of Brain heart infusion broth (37 gm/l), sucrose (5 gm/l), agar number 1 (10 gm/l) and Congo red dye (0.8 gm/l). Congo red stain was prepared as concentrated aqueous solution and autoclaved at 1210C for 15 minutes. Then it was added to autoclaved Brain heart infusion agar with sucrose at 550C.

How to prepare Congo red stain for jcdr?

The medium composed of Brain heart infusion broth (37 gm/l), sucrose (5 gm/l), agar number 1 (10 gm/l) and Congo red dye (0.8 gm/l). Congo red stain was prepared as concentrated aqueous solution and autoclaved at 1210C for 15 minutes. Then it was added to autoclaved Brain heart infusion agar with sucrose at 550C.

How to prepare Congo red for biofilm detection?

Congo Red Method The medium composed of Brain heart infusion broth (37 gm/l), sucrose (5 gm/l), agar number 1 (10 gm/l) and Congo red dye (0.8 gm/l). Congo red stain was prepared as concentrated aqueous solution and autoclaved at 1210C for 15 minutes.