Staphylococcus aureus is a type of bacteria that can be grown on various types of culture media, including CLED (cystine lactose electrolyte deficient) agar.
CLED agar is a type of differential medium that is commonly used for the isolation and identification of urinary tract pathogens.
Staphylococcus aureus on CLED agar
The culturing procedure for Staphylococcus aureus on CLED agar is similar to that of other bacteria. Here are the basic steps:
- Sterilize the CLED agar plates in an autoclave and allow them to cool to room temperature.
- Inoculate the plate with a small amount of Staphylococcus aureus from a pure culture using a sterile loop or swab.Â
- Spread the bacteria evenly across the surface of the plate. Incubate the plate at 35-37°C for 18-24 hours in an aerobic atmosphere.
- After incubation, examine the plate for the growth of Staphylococcus aureus.
E. coli on CLED agar
Escherichia coli, commonly referred to as E. coli, is a gram-negative bacterium that typically appears as yellow or yellow-green colonies on CLED (cystine lactose electrolyte deficient) agar, which is commonly used for the isolation and identification of urinary tract pathogens.
E. coli is a lactose-fermenting organism that can grow well on CLED agar, but it may produce smaller colony sizes compared to other agar media.
The ability of E. coli to ferment lactose on CLED agar is evidenced by the yellow color of the colonies, which is a result of the acid produced during lactose fermentation.
Streptococcus on CLED agar
Streptococcus is a group of gram-positive bacteria that grow on CLED (cystine lactose electrolyte deficient) agar. This medium is commonly used to identify urinary tract pathogens.
The appearance of colonies may vary according to the species of Streptococcus, but they are typically small, opaque, and white or gray.
Differentiating between Streptococcus species may require further tests, such as hemolysis testing, selective or enriched media growth, and pH or nutrient requirements.
Streptococcus in the urinary tract can cause various illnesses, such as strep throat and necrotizing fasciitis.
Early and accurate identification of species on CLED agar is imperative for managing and treating illnesses related to these bacteria.
Pseudomonas on CLED agar
Pseudomonas is a type of gram-negative bacterium that can be grown on CLED (cystine lactose electrolyte deficient) agar, which is commonly used for the identification and isolation of urinary tract pathogens.
This bacterium typically appears as green or blue-green colonies on the CLED agar medium, which is due to the pyocyanin pigment production.
Pyocyanin is a blue-green pigment produced by certain strains of Pseudomonas leading to the appearance of the blue-green coloration of colonies.
Pyocyanin, together with other pigments, is involved in bacterial adaptation to different environmental conditions.
The blue-green color of Pseudomonas colonies can be helpful in identifying this bacterium.
Klebsiella on CLED agar
Klebsiella is a gram-negative bacterium that can grow on CLED (cystine lactose electrolyte deficient) agar, which is commonly used for the identification and isolation of urinary tract pathogens.
The appearance of colonies may vary according to the species of Klebsiella, but they are typically large, mucoid, and pale-yellow in color.
Klebsiella is known to cause a range of infections including pneumonia, urinary tract and blood infections, and is associated with a higher risk of healthcare-associated infections.
Therefore, early and accurate identification of Klebsiella species is crucial for the appropriate management and treatment of these infections.
Pink colonies on CLED agar
Pink colonies on CLED (cystine lactose electrolyte deficient) agar may indicate the presence of Proteus mirabilis, which is a type of gram-negative bacterium that is able to ferment lactose.
When Proteus mirabilis is grown on CLED agar, it forms pink-colored colonies due to its lactose fermentation ability.
It’s worth noting that Proteus mirabilis is a common cause of urinary tract infections, especially in people with urinary catheters or other medical devices such as a stent.
Therefore, the appropriate identification and management of Proteus mirabilis infections are critical for effective treatment.
Salmonella on cled agar
Salmonella is a gram-negative bacterium that can grow on CLED (cystine lactose electrolyte deficient) agar, but it is not the optimal medium for its isolation as it lacks selective agents.
Salmonella colonies on CLED agar may appear pale yellow and translucent.
To improve the isolation of Salmonella from clinical specimens, it is recommended to use selective media, such as MacConkey agar or Salmonella-Shigella agar.