What is a Baird-Parker agar plate used for?
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What is a Baird-Parker agar plate used for?
Baird- Parker Agar is widely used and is included in many standard procedures for testing foods, cosmetics, or swimming pool waters for the presence of Staphylococcus aureus. 2-6 It may also be used for the isolation of S. aureus from clinical specimens and is also called Egg- Tellurite-Glycine-Pyruvate Agar (ETGPA).
What makes Baird Parker selective?
Sodium pyruvate was added as a selective growth stimulant, and egg yolk emulsion as a differentiation agent. The medium allows the growth of Staphylococcus aureus and selectively inhibits the growth of most other bacteria….Composition of Baird Parker Agar.
| Ingredients | Gms/liter |
|---|---|
| Lithium chloride | 5.000 |
| Agar | 20.000 |
How would you distinguish between members of the genus Staphylococcus on Baird Parker?
Differentiation between members of the Genus Staphylococcus is possible: coagulase-positive staphylococci appear as shiny, gray-black, convex colonies with a clear zone surrounding the colonies; while coagulase- negative staphylococci grow poorly and appear as small, dull black colonies while clear or opaque zones are …
Why is egg enrichment added after sterilization?
The addition of sulfamethazine (optional) after autoclaving inhibits most Proteus and thus limits the invasion of the medium by this species. Enrichment with egg yolk aids in identification by showing the action of lecithinase.
What does it mean to be coagulase positive?
If ‘positive’ (e.g., the suspect colony is S. aureus), the plasma will coagulate, resulting in a clot (sometimes the clot is so pronounced, the liquid will completely solidify). If ‘negative’, the plasma remains a liquid. The negative result may be S.
What is coagulase positive staph?
Coagulase positive staphylococci are known human pathogens. Transmission of these organisms occurs through direct contact with colonized or infected persons or through indirect contact with contaminated objects. S. aureus is the most common species in this group; additional species include S. lugdunensis and S.
What characteristics distinguish Staphylococcus species from most other species?
Staphylococcus aureus aureus are cocci that form irregular grape-like clusters. They are non-motile, non- sporing and catalase positive. They grow rapidly and abundantly under aerobic conditions. On blood agar, they appear as glistening, smooth, entire, raised, translucent colonies that often have a golden pigment.
How is pathogenic Staphylococcus aureus distinguished from other species of Staphylococcus?
aureus is often considered to be the most problematic of the three pathogens and is distinguished from the other two by being the only one able to coagulate plasma. S. aureusis able to cause many superficial pyogenic (pus-forming) infections of the dermis and underlying tissues as well as serious systemic infections.
How do you make Baird-Parker agar?
Heat with frequent agitation and boil for one minute to completely dissolve the medium. Autoclave at 121°C for 15 minutes. After cooling to 45- 50°C, add 50 mL of egg yolk tellurite supplement and 3 ml sterile 3.5% potassium tellurite solution or 50 ml egg yolk tellurite emulsion. Mix thoroughly before dispensing.
What are the 2 types of coagulase test?
Coagulase is of two types; free coagulase and bound coagulase, each of which is detected by different methods. The bound coagulase is called the clumping factor and is detected rapidly by a slide test. The free coagulase, in turn, is detected in the test tube as a result of the formation of a clot.
What are the two types of staphylococcal coagulase?
Coagulase is an enzyme-like protein and causes plasma to clot by converting fibrinogen to fibrin. Staphylococcus aureus produces two forms of coagulase: bound and free. Bound coagulase (clumping factor) is bound to the bacterial cell wall and reacts directly with fibrinogen.
What is the classification of Staphylococcus?
| Staphylococcus | |
|---|---|
| Phylum: | Bacillota |
| Class: | Bacilli |
| Order: | Bacillales |
| Family: | Staphylococcaceae |
What is the principle of coagulase test?
Principle of Coagulase Test Bound coagulase (clumping factor) is bound to the bacterial cell wall and reacts directly with fibrinogen. This results in an alternation of fibrinogen so that it precipitates on the staphylococcal cell, causing the cells to clump when a bacterial suspension is mixed with plasma.
How can you differentiate between Staphylococcus aureus and Staphylococcus epidermidis?
The key difference between epidermidis and aureus is that Staphylococcus epidermidis is a non-haemolytic bacterium while Staphylococcus aureus is a haemolytic bacterium. Epidermidis and aureus are species names of two bacteria in the bacterial genus Staphylococcus.
What does coagulase negative and positive mean?
aureus is generally coagulase-positive, meaning that a positive coagulase test would indicate the presence of S. aureus or any of the other 11 coagulase-positive Staphylococci. A negative coagulase test would instead show the presence of coagulase-negative organisms such as S. epidermidis or S. saprophyticus.
What’s the definition of staphylococci?
Definition of staphylococcus : any of a genus (Staphylococcus) of nonmotile gram-positive spherical bacteria that occur singly, in pairs or tetrads, or in irregular clusters and include causative agents of various diseases (such as skin infections, food poisoning, and endocarditis)
What is the taxonomy of Staphylococcus aureus?
| Taxonomy ID | 1280 |
|---|---|
| Rank | species |
| Lineage | cellular organisms, Bacteria, Terrabacteria group, Firmicutes, Bacilli, Bacillales, Staphylococcaceae, Staphylococcus, Staphylococcus aureus |
| Genetic Code | 11 |
What are the two types of coagulase test?
