What are the general categories used to describe colony morphology?
Why is it important toidentify colony morphology? The general categories used are elevation, margin, texture, opacity, color/pigment and size. This is essential part is assisting in identifying bacteria.
What is the relationship between morphology and colony?
Morphology of colonies can be defined as their color, shape, edge and elevation. These features are observed with the naked eye by looking at the colony itself. However, cellular morphology shows the difference of the individual cells that is seen under the microscope.
Why is it important to identify colony morphology?
Colony morphology is a method that scientists use to describe the characteristics of an individual colony of bacteria growing on agar in a Petri dish. It can be used to help to identify them. Use the diagrams on colony morphology to help you interpret your plate.
What is the colony morphology of Bacillus subtilis?
Bacillus subtilis is a typical germ, which is rod-shaped and Gram-positive. When cultured on ordinary nutrient agar, the morphology circular colony of this bacteria is rough, opaque, fuzzy white or slightly yellow with jagged edges [1, 7].
How do you identify bacillus?
Bacillus species are rod-shaped, endospore-forming aerobic or facultatively anaerobic, Gram-positive bacteria; in some species cultures may turn Gram-negative with age.
What is the colony morphology of Staphylococcus aureus?
S. aureus is a facultatively anaerobic, Gram-positive coccus, which appears as grape-like clusters when viewed through a microscope, and has round, usually golden-yellow colonies, often with hemolysis, when grown on blood agar plates.
Can Bacillus subtilis grow on MacConkey Agar?
Bacillus subtilis does not grow on MacConkey Agar. It grows on nutrient agar, and is positive on all enzyme tests. Enterococcus faecalis does not go on the synthetic medium but does grow on the tryptic soy broth and the SF broth. This microorganism was negative on all enzyme tests.
What bacteria grows in 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.
What color is salmonella on MacConkey Agar?
Result Interpretation on MacConkey Agar
| Organisms | Growth results |
|---|---|
| Enterobacter, Klebsiella | Mucoid, pink colonies |
| Proteus | Colorless colonies, swarming growth |
| Salmonella, Shigella | Colorless colonies, or sometime medium color: orange to amber |
| Pseudomonas | Irregular, colorless to pink colonies |
Does Salmonella grow on nutrient agar?
Media used for Salmonella identification are those used for identification of all Enterobacteriaceae. Most Salmonella strains are motile with peritrichous flagella, however, nonmotile variants may occur occasionally. Most strains grow on nutrient agar as smooth colonies, 2-4 mm in diameter.
Can S aureus grow on MacConkey Agar?
MacConkey agar selects for organisms like Escherichia coli (Gram negative bacilli) while inhibiting the growth of organisms like Staphylococcus aureus (Gram positive cocci).
What organisms are inhibited from growing on MacConkey Agar?
MacConkey agar not only selects for Gram-negative organisms by inhibiting Gram-positive organisms and yeast but also differentiates the Gram-negative organisms by lactose fermentation. Lactose ferments will stain pink while the nonlactose ferments will be clear colonies.
Why do we use blood agar?
Many species of bacteria produce toxic by-products that are capable of destroying red blood cells. Blood agar is a general purpose enriched medium often used to grow fastidious organisms and to differentiate bacteria based on their hemolytic properties.