Micro Exam 4 Staphylococcus aureus

What is Alpha toxin (α-toxin)?

*Alpha toxin (α-toxin)* - kills host cells by creating holes in their membranes that cause cell contents to leak out.

What is Clumping Factor?

*Clumping Factor* - causes suspension of S. aureus cells to clump together in the presence of fibrinogen and fibrin in blood plasma. This aids S. aureus in wound colonization where blood plasma is oozing.

What is Coagulase?

*Coagulase* - a Protein that causes blood to clot by converting fibrinogen to fibrin. Coagulase is found on surface of the bacterial cell. Not conclusively shown to be a virulence factor but fibrin coated S. aureus are resistant to phagocytosis (immune system avoidance.)

_____ is the causitive agent of SSSS.

*Staphylococcus aureus* is the causitive agent of SSSS.

Toxin-1 along with a few other toxins caused a massive release of ____.

Toxin-1 along with a few other toxins caused a massive release of *cytokines*.

Toxin-1 is a _____ (causes a strong immune response.)

Toxin-1 is a *superantigen* (causes a strong immune response.)

Toxins called _____ cause the symptoms of SSSS.

Toxins called *exfoliatins* cause the symptoms of SSSS.

Exfoliatins cause the dead outer layer of epidermis to separate from living layer just beneath. True or False?

True.

Toxic shock syndrome can occur with any type of S. aureus infection. Not just with tampons. A particular kind of tampon enhanced the opportunity for the disease to occur. True or False?

True.

Individual boils can cluster together and form an interconnected network of boils called ____. In severe cases, boils may develop to form _____.

Individual boils can cluster together and form an interconnected network of boils called *carbuncles*. In severe cases, boils may develop to form *abscesses*.

Is Staphylococcus aureus Gram Positive or Gram Negative?

It is *Gram Positive*. Gram (+) coccus (spheres). Seen under microscope as clusters resembling grapes.

More correctly it is called ______.

More correctly it is called *staphylococcus toxic shock syndrome*.

Because the outer layer of dead skin cells is removed there is often no scaring after healing. True or False?

True.

Cytokine release caused a drop in blood pressure and kidney failure that could be fatal. True or False?

True.

Exfoliatins enter the bloodstream from site of infection and are carried to large areas of the skin. True or False?

True.

Lipid break down may allow S. aureus to progress down into the follicle causing infection. True or False?

True.

More absorbent brand of tampon was causing abrasion to the vaginal wall letting S. aureus toxins into the bloodstream. True or False?

True.

Pathogenicity due to a variety of virulence factors such as toxins, enzymes, capsule, superantigens, and agents that destroy immune cells or inhibit their effectivenes. True or False?

True.

S. aureus is not present in the blister fluid; no infection at site. True or False?

True.

S. epidermidis prevents colonization of skin by pathogens. True or False?

True.

Staph infections are common in surgical wounds and a major problem in hospitals (nosocomial infections.) True or False?

True.

Staphylococci are salt tolerant - thrive on skin even where salts from sweat accumulate. True or False?

True.

Staphylococci such as S. epidermidis and S. aureus are normal flora of the skin. True or False?

True.

Staphylococcus aureus are the most pathogenic of the Staphylococci. True or False?

True.

Toxic Shock Syndrome Was not due to an infection but from S. aureus growth in menstrual fluid. True or False?

True.

Toxin Shock Syndrome is caused by Staphylococcus. True or False?

True.

Notorious outbreak of Toxic Shock Syndrome is caused by super absorbent tampons. True or False?

True. -Some originally thought it was a new disease caused by the tampons but was actually S. aureus.

Staphylococcus aureus

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TSS Epidemiology

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What is Hyaluronidase?

*Hyaluronidase* - enzyme that degrades hyaluronic acid which holds cells together in host tissue. Assist S. aureus in invading and destroying host tissues.

What is Leukocidin?

*Leukocidin* - kills neutrophils (phagocytic cells) by creating holes in their membranes and causing cell components to leak. Neutrophils normally advance to wound to remove invading microbes. Leukocidin helps S. aureus avoid host defenses.

____ enzyme produced by S. aureus may break down oils/lipids in sebum that protect the hair follicle.

*Lipase* enzyme produced by S. aureus may break down oils/lipids in sebum that protect the hair follicle.

What is Protein A?

*Protein A* - hides bacteria from phagocytic cells. Binds IgG by the Fc portion of the antibody, coating the bacteria with the Fab portion of the antibody sticking out. This blocks Fc receptors on phagocytic cells and prevents engulfment.

____ is the prominent species on skin.

*S. epidermidis* is the prominent species on skin.

____ is an oily substance secreted by the sebaceous gland to waterproof skin and hair and to help retain moisture.

*Sebum* is an oily substance secreted by the sebaceous gland to waterproof skin and hair and to help retain moisture.

____ are the most common skin bacteria.

*Staphylococci* are the most common skin bacteria.

S. aureus produces several virulence factors in wound infections. What are these?

-Coagulase -Clumping Factor -Protein A -Hyaluronidase -Leukocidin -Alpha toxin (α-toxin)

Staphylococcus aureus causes a wide variety of infections. What are these?

-Wound infections -Skin infections -Bone infections -Heart infections

What are symptoms of Folliculitis?

-Presents as a small red bump or pimple -Bump usually exhibited at the involved follicle -Often hair can be pulled and the infection goes away absent further treatment -Infection can spread from infected follicle to adjacent tissues -Causes localized redness, swelling and tenderness -The lesion produced is called a *furuncle*.

Infections caused by S. aureus.

-Skin Infections -Wound Infections -Heart Infections -Bone Infections

What are the symptoms of Scalded Skin Syndrome?

-Skin appears scalded often over most or all of the body -Skin becomes wrinkled and form blisters with clear fluid -Skin becomes tender and looks like sandpaper

Hair Follicle Infections

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Hot Tub Folliculitis

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Infections caused by S. aureus

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Look at slide 13

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Look at slide 17

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Look at slide 26

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Look at slide 8

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Look at slides 10-11.

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Pathogen Factor

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S. Aureus and SSSS

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S. Aureus and Wound Infections

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SSSS and Pathogenesis

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Scalded Skin Syndrome

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Toxic Shock Syndrome

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Toxin-1 (TSST-1)

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Wound Infection - Virulence Factors

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Because outer layer of skin is removed there is fluid loss like when skin is burned and risk of potentially fatal secondary infection (especially from _______. )

Because outer layer of skin is removed there is fluid loss like when skin is burned and risk of potentially fatal secondary infection (especially from *P. aeruginosa*. )

Boil or ____ is a skin disease caused by the inflammation of hair follicles, thus resulting in the localized accumulation of pus and dead tissues.

Boil or *furuncle* is a skin disease caused by the inflammation of hair follicles, thus resulting in the localized accumulation of pus and dead tissues.

Bone infections consist of?

Bone infections - osteomyelitis.

What are Carbuncles?

Carbuncles - *clusters* of boils or large infected area of the skin. Characterized by drainage of pus. Develop where skin is thick such as the back of the neck

What is the drug resistance for Staphylococcus aureus?

Drug resistance - resistant to penicillin despite being Gram (+).

What is Foliculitis?

Foliculitis - infection of hair follicle that can lead to formation of furuncles and carbuncles.

What are Furuncles?

Furuncles - inflamation of the hair follicle that affects adjacent tissue resulting in a boil.

Heart Infections consist of?

Heart infection - endocarditis (infection of heart valves.)

Hot Tub Folliculitis is usually caused by ____not S. aureus.

Hot Tub Folliculitis is usually caused by *Pseudomonas aeruginosa* not S. aureus.

If a wound infection spreads to circulation, ____ is produced.

If a wound infection spreads to circulation, *fever* is produced.

SSSS happens most to ___.

SSSS happens most to *infants*.

Skin Infections consist of?

Skin infections - carbuncles, impetigo, furuncles, folliculitis.

Some strains are becoming resistant to drugs like ____.

Some strains are becoming resistant to drugs like *Methicillin*.

Staph infected wounds produces what symptoms?

Staph infected wounds produces *pus, inflammation, swelling, redness and pain*.

Staphylococcal Scalded Skin Syndrome is known as ____.

Staphylococcal Scalded Skin Syndrome is known as *SSSS*.

The main toxin was _____.

The main toxin was *toxin-1 (TSST-1)*.

Wound Infections consist of?

Wound infections - surgical wound infections are common.