Staphylococcus

*-What does Exfoliating Toxin do?

It degrades Desmoglein 1 (so causes abscesses/sores)

Where is staphylococcus encountered

It is a normal inhabitant of the SKIN and or Mucosal Surfaces of warm blooded animals and humans -Staphylococci are Oportunistic pathogens. They are not particularly invasive - usually some other damage to the skin predisposes infection

What does Protein A do. What is it

It is a virulence factor of Staph that helps resist phagocytosis. It binds to the heavy chain of the IgG and thus prevents binding to the Fc region of Effector Cells

Virulence Genes encoded on Genomic Islands

Phenol-soluble modulin

Principal pathogenic species of Staphylococcus

S. Aureus

Are staphylococcus opportunistic pathogens

Yes! They are not particularly invasive it is Usually some other damage to the Skin that predisposes the infection

How does Staphylococci Adhere to its host

-Adhesion is thought to be mediated by Protein A & Fibronectin binding proteins -Hosts extracellular matrix has Fibronectin and Laminin that the Staph can adhere to -Also adheres by a biofilm - assemblage of microbes attached to a surface. Contains microbes, Polysaccharide Slime, and Proteins

What does Enterococcus Cecorum affect and cause?

-E. Cecorum affects Broiler Chickens -Causes osteomyelitis in these broilers. The will eventually have collapse of the vertebral column

Describe characteristics of staphylococcus

-Gram Positive -Cocci (tetrad) -Facultative Anaerobes (don't make gas though) -Catalase Positive -Non-Motile -Non-Spore Forming

Characteristics of Enterococci

-Gram Positive -Coccibacilliary (football/oval shape) -May be Weakly catalase positive or negative -Small White to Grey Convex colonies *-Alpha to Gamma Hemolytic

Staphylococcus hyicus is known as what. What is the mechanism

-Greasy Pig Disease -Exfoliating toxin degrades Desmoglein which results in splitting/separating of the Epidermis at the granular layer resulting in the lesions

Where is staph. Epidermidis Found

-Human Skin -Skin, Teats, Hair, Mucosa of many animals but less than humans

Where else to enterococcus infections occur

-Otitis - dog steps in poop then scratches ear with foot -Urinary Tract (UTI) and cause Metritis - wind sucking horses whose poop contaminates the vulva -Circulatory system - likes to attach to veins and artery linings -Sepsis -Common agent in anal glad abscesses -Metritis in Sows - spread by AI in boar semen that contains Cytolysins of L and S E. Faecalis

What are important virulence factors of Staph

-Protein A and Polyuronic Acid Capsules - resistance to phagocytosis -Carotenoids and Catalase - counter oxidative burst -Coagulase - help the microbes wall off so antibiotics can't get to them -Hyaluronidase and Hydrolase - cause host tissue degradation and necrosis

What makes staphylococcus so hardy and resistant to environmental stress

-Resists dehydration and heat -Tolerate many common Disinfectants -Catalase Positive

Staph has soluble and insoluble virulence factors. What does this mean

-Soluble Virulence factors - can be secreted by the bacteria or be a product of the bacteria. So the bacteria doesn't necessarily have to be present to cause infection -Insoluble virulence factors - mostly on the surface of the bacteria so bacteria have to be present to cause disease -Protein A -Teichoic Acids -Capsule -Clumping factor

*-What are methicillin resistant staphylococci?

-Strains of staphylococci that contain Penicillin Binding Protein Type 2. -It is a Beta Lactamase

S. Pseudintermedius causes what in dogs and cats

-Superficial staphylococcal Pyoderma -Generalized Staphylococcal Folliculitis **-Also found in UTIs leading to uroliths -Ocular Infections -Otitis Externa and Media -Often due to multiple drug resistance

What drug are we MOST concerned about becoming resistant to enterococcus in human hospitals? Why?

-Vancomycin -We are worried that if enterococcus becomes resistant to vancomycin then staphylococcus aureus will also become resistant to vancomycin *-So we avoid using it in vet med at all costs

What are Staphylococcus Aureus human diseases

1. Generalized Exfoliative Dermatitis 2. Toxic Epidermal Necrolysis 3. Bullous Impetigo and Staph Scarlatina *-Collectively called Staphylococcal Scalded Skin Syndrome

What are the stages of abscess formation

1. Release of bacterial products and host complement cause release of neutrophil chemotactic factors 2. So then infiltration of neutrophils 3. Neutrophil Lysis by Staph Leukocidin 4. Damaged neutrophils release lysosomal enzymes & these combined w/ staph enzymes cause tissue damage and necrosis

What are the pathogenic species of staphylococcus

1. S. Aureus - coagulase + 2. S. Intermedius - Intermedius, Pseudintermedius, Delphini - coagulase + 3. S. Schleiferi - coagulase + (emerging in cats and dogs) 4. S. Hyicus - coagulase variable 5. S. Epidermidis - coagulase negative 6. S. Chromogenes - coagulase negative

How do we determine of staph is coagulase positive

16 S rRNA (but doesn't determine species)

Hallmark clinical manifestation of Staph

Abscess Formation

Biofilms make Staph more resistant to what

Antibiotics Oxidative Stress Phagocytosis

What are biofilms used for?

Attachement. They are an assemblage of microbes attached to a surface and contain Polysaccharide slime and Proteins Staph living in biofilms are moreresistant to phagocytosis, oxidative stress, and antibiotics

Enterococcus can grow in

Bile, Esculin, and Salt Broth

Abscesses are "walled off" is this good or bad

Both. -The host sees it as containing the invading organism but it also means antibiotics cant get to the bacteria -Also if its in or near vital organ it can cause death

What is bumble Foot

Caused by Staph. Aureus when animal has a cut on the foot and aureus enters

Enterococcus is resistant to which drug class

Cephalosporins

S. Pseudintermedius most prevalent staph in?

Dogs and Cats Only Coagulase + that is Beta Galactosidase Positive

Enterococcus most common in mammals

E. Faecalis and E. Faecium

This bacteria can be found in boars semen and be spread by coitus or AI causing Metritis in Sows.

Enterococcus

Virulence genes encoded on S. Aureus pathogenicity islands (SCCs)

Enterotoxins and Adherence Proteins Bap

Virulence genes encoded on Bacteriophages

Exfoliative Toxins

Virulence genes on mobile genetic elements (plasmids, bacteriophages)

Exfoliative Toxins

MRSA and MRSP isolates will all have what

Exfoliative genes

Many Enterococcus infections are the result of what?

Feces contamination of wounds or incisions

Enterococcus Is found where

It is part of the normal flora of all animals GI tract. It is found pretty much everywhere because it is passed in the poop. It is an opportunistic bacteria

Describe S. Aureus

Makes Yellow/Gold Colonies. The color is caused by carotenoid pigment Staphyloxanthin

MGEs are what

Mobile Genetic Elements (plasmids, bacteriophages)

Characteristics of S. Epidermidis

Non-pigmented to tan colonies. Coagulase Negative

What type of Staph has the pigment Staphyloxanthin and what is the significance of the pigment

S. Aureus. It may be a virulence factor that causes Aureus to reduce phagocytosis and oxygen dependent killing mechanisms by phagocytes

What staph is the most severe and difficult to treat relating to mastitis

Staph. Aureus -Treatment only effective in 50% of cases. Spread by milking

Organisms of this genus are among the most hardy, most resistant to environmental stress of all the non-spore forming organisms

Staphylococcus

What genera belongs to the Family Micrococaceae

Staphylococcus

Toxic Shock Syndrome is caused by what bacteria

Staphylococcus Aureus

Enterococci are part of which family

Streptococcus

General Pathogenesis of Staph

Suppurative Infections -Abscess formation -Pneumonia, osteomyelitis, meningitis if invades deeper tissue -Toxic Shock Syndrome

What should we do to treat Enterococcus

Take a culture and do a Susceptibility (MIC) test. Then base the drug we use off the MIC for that enterococcus strain

Negative staining of desmoglein means what?

That it is damaged

How does Toxic Shock syndrome work

The bacteria are at the site of the infection and produce the Toxin (TSST-1) which then enters the blood stream. -TSST-1 is called a "super antigen" because it causes the recruit of too many Lymphocytes and you get way to many Cytokines produced leading to hypotension and Shock (Cytokine Storm)