Quick Answer: When Viewed Under A Microscope What Differentiates The Staphylococci From The Streptococci?

Does Streptococcus grow on MSA?

Both streptococcal organisms are catalase negative and beta-hemolytic on sheep blood agar plates.

Also, neither would grow on the mannitol salt agar.

Streptococcus pyogenes is sensitive to growth inhibition by bacitracin, whereas Streptococcus agalactiae (group B streptococci) is not..

Which of the following tests is used routinely to identify Staphylococcus aureus?

slide coagulase testWhich of the following tests is used routinely to identify Staphylococcus aureus? The slide coagulase test using rabbit plasma with ethylenediaminetetraacetic acid (EDTA) detects bound coagulase or “clumping factor” on the surface of the cell wall, which reacts with the fibrinogen in the plasma.

What are the negative effects of normal flora?

Members of the normal flora may cause endogenous disease if they reach a site or tissue where they cannot be restricted or tolerated by the host defenses. Many of the normal flora are potential pathogens, and if they gain access to a compromised tissue from which they can invade, disease may result.

What test is used to distinguish between staphylococci and streptococci?

catalase testThe catalase test is a particularly important test used to determine whether the Gram + cocci is a staphylococci or a streptococci. Catalase is an enzyme that converts hydrogen peroxide to water and oxygen gas.

What is the difference between staphylococcus and streptococcus?

Staphylococci are Gram-positive cocci that grow in clumps, are catalase test positive and coagulase test positive ( Staph. … Streptococci are Gram-positive cocci that grow in pairs or chains. They are readily distinguished from staphylococci by their Gram-stain appearance and by a negative catalase test.

What does the term normal microbial flora mean?

What does the term “normal microbial flora” mean? It means the normal microbes/bacteria that is found in the body, especially in the mouth and upper respiratory tract.

Which class of microbes Gram positive or Gram negative are more sensitive to lysozyme and why?

Penicillin. Which class of microbes (Gram-positive or Gram-negative) are more sensitive to lysozyme and why? Gram-positive bacteria are more sensitive to lysozyme because of gram-negative presence of an outer membrane in the latter.

What is the advantage of normal flora?

These normal flora provide us with many benefits, which include: They prevent colonization by pathogens by competing for attachment & nutrients. Some synthesize vitamins that are absorbed as nutrients by the host (e.g. K & B12). Some produce substances that inhibit pathogenic species.

What tests are used to identify Staphylococcus?

Diagnosis is based on performing tests with colonies. Tests for clumping factor, coagulase, hemolysins and thermostable deoxyribonuclease are routinely used to identify S aureus. Commercial latex agglutination tests are available. Identification of S epidermidis is confirmed by commercial biotyping kits.

How can Staphylococcus be differentially tested?

How can Staphylococcus be differentially tested? A bacterial swab is taken from a patient with impetigo and streaked across an MSA plate. … The causative agent of impetigo is staph aureus, a Gram-positive bacterium capable of fermenting mannitol.

What does Staphylococcus aureus look like on blood agar?

Individual colonies on agar are round, convex, and 1-4 mm in diameter with a sharp border. On blood agar plates, colonies of Staphylococcus aureus are frequently surrounded by zones of clear beta-hemolysis. … S. aureus can infect other tissues when barriers have been breached (e.g., skin or mucosal lining).

Where is normal flora not found in the body?

Newborn exposed to microbes at birth will become part of normal flora. … Where is normal flora not found in the human body? Blood, lungs, brain/spinal fluid, kidneys, heart. What is an opportunistic pathogen?