Staphylococcus Quiz on Clinical Relevance

False (B)

It clots citrated plasma.

<p>antibiotics</p> Signup and view all the answers

<p>Staphylococcus aureus = Causes food poisoning via enterotoxins Coagulase-negative Staphylococci = Often harmless commensals Staphylococcus epidermidis = Typically associated with infections related to prosthetic devices Staphylococcus saprophyticus = Commonly causes urinary tract infections</p> Signup and view all the answers

<p>Golden yellow pigment (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Blood agar or mannitol salt agar</p> Signup and view all the answers

<p>alpha or beta</p> Signup and view all the answers

<p>Staphylococcus aureus = Golden yellow pigment Staphylococcus saprophyticus = Lemon yellow pigment Staphylococcus epidermidis = White pigment</p> Signup and view all the answers

<p>Catalase test (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>35-37°C</p> Signup and view all the answers

<p>coagulase</p> Signup and view all the answers

<p>Presence of coagulase clumping (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Catalase test = Differentiates staphylococci from streptococci Coagulase test = Detects presence of coagulase enzyme Mannitol fermentation test = Checks ability to ferment mannitol Hemolysis test = Examines the breakdown of red blood cells</p> Signup and view all the answers

<p>Deoxyribonuclease (DNase)</p> Signup and view all the answers

<p>Bubbles appear immediately (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>positive</p> Signup and view all the answers

<p>Slide coagulase test = Detection of membrane bound coagulase Tube coagulase test = Detection of extracellular free coagulase DNase test = Detection of deoxyribonuclease enzyme Mannitol fermentation test = Detection of mannitol fermentation</p> Signup and view all the answers

<p>Rabbit or human plasma</p> Signup and view all the answers

<p>Ability to ferment mannitol (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Lemon yellow (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Blood agar</p> Signup and view all the answers

<p>blood agar</p> Signup and view all the answers

<p>Staphylococcus aureus = Golden yellow Staphylococcus saprophyticus = Lemon yellow Staphylococcus epidermidis = White Staphylococcus haemolyticus = Red</p> Signup and view all the answers

<p>40-50% (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Coagulase</p> Signup and view all the answers

<p>cocci</p> Signup and view all the answers

<p>Staphylococcus aureus = Coagulase positive Staphylococcus epidermidis = Coagulase negative Coagulase-negative staphylococci = Common skin flora Staphylococcus saprophyticus = Urinary tract infections</p> Signup and view all the answers

<p>Beta hemolysis (D)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>coagulase</p> Signup and view all the answers

<p>35-37</p> Signup and view all the answers

<p>Catalase Test = Detects the presence of catalase enzyme Coagulase Test = Detects the presence of coagulase enzyme Mannitol Salt Agar = Differentiates mannitol fermentation Blood Agar = Identifies hemolytic activity</p> Signup and view all the answers

A gram-positive bacteria commonly found on human skin and mucous membranes. Can cause infections, especially in immunocompromised individuals or those with existing medical conditions.

Staphylococcus aureus is found in many places where humans are present, such as on skin, mucous membranes, and in nasal passages.

Characteristics of a microorganism that enable it to cause disease. Ex: Coagulase, toxins, etc.

Collect clinical samples (swabs, tissue, blood) to test, following sterile procedures.

Some Staphylococcus strains can withstand the effects of common antibiotics, making treatment more challenging.

Gram-positive cocci appearing in clusters (like grapes) under a microscope after Gram staining.

Nutrient-rich media like blood agar or mannitol salt agar used to grow Staphylococci, facilitating their identification.

Different Staphylococcus species produce distinct pigments (yellow, white) as a diagnostic feature.

Some Staphylococci exhibit hemolysis patterns (alpha or beta) on blood agar, aiding in their identification.

Staphylococci are facultative anaerobes, growing well with or without oxygen.

A test used to differentiate staphylococci (catalase-positive) from streptococci (catalase-negative) by observing bubble production from a hydrogen peroxide solution.

Bacteria that produce bubbles when exposed to hydrogen peroxide.

A test to detect the presence of coagulase enzyme in bacteria, which causes blood plasma to clot.

An enzyme produced by some bacteria that causes blood plasma to clot.

Describes bacteria that produce coagulase, causing blood plasma to clot.

A group of bacteria characterized by their morphology (spherical or round shape and Gram-positive staining) and arrangement in clusters.

Examining bacteria under a microscope.

A test to detect the presence of membrane-bound coagulase (clumping factor) in bacteria. A positive result is indicated by clumping of bacterial cells when mixed with plasma within 10 seconds.

This test detects extracellular free coagulase. A positive result occurs when plasma is converted into a clot in the tube.

This test identifies the presence of the enzyme deoxyribonuclease (DNase) in bacteria. A positive result is shown by a clear zone around the bacterial colony on the agar plate.

MSA contains 7.5% sodium chloride (NaCl), which inhibits the growth of most bacteria except staphylococci.

MSA contains mannitol sugar and a pH indicator (phenol red). Staphylococci that ferment mannitol produce acid, turning the medium yellow.

Pathogenic Staphylococcus aureus ferments mannitol, turning the MSA medium yellow. Coagulase-negative staphylococci do not ferment mannitol.

The mannitol fermentation test is used in the clinical microbiology lab to identify and differentiate Staphylococcus species. It helps to distinguish pathogenic Staphylococcus aureus from other staphylococci.

Staphylococci are Gram-positive cocci that typically appear in clusters, resembling bunches of grapes.

Staphylococci are commonly found on the skin and mucous membranes of humans and animals. They are ubiquitous.

Staphylococcus aureus is a prominent species of staphylococci that can cause various infections, including skin infections, food poisoning, and pneumonia.

The Coagulase Test differentiates Staphylococcus aureus from other staphylococci by detecting the coagulase enzyme produced by S. aureus.

Some Staphylococcus species can be opportunistic pathogens, causing infections in immunocompromised individuals or those with weakened defenses.

Staphylococcus aureus produces a golden-yellow pigment called carotenoid.

Staphylococci appear as clusters of round bacteria that stain purple under a microscope after Gram staining.

Some Staphylococcus species can break down red blood cells in blood agar. This is called hemolysis.

Staphylococci need a rich environment to grow well. Nutrient-rich media provide the necessary components for their growth and development.

Staphylococcus aureus is characterized by its positive results in both catalase and coagulase tests. It produces catalase, which breaks down hydrogen peroxide, and coagulase, which causes the clotting of blood plasma.

Mannitol Salt Agar (MSA) is specifically designed to both select for staphylococci and differentiate them based on their ability to ferment mannitol. The high salt concentration inhibits most bacteria except staphylococci, while mannitol fermentation causes a color change in the media.