Lecture 11: Staphylococcus

Question 1

Is staphylococcus gram positive or negative

Answer 1

Positive

Question 2

What test differentiates staphylococcus from streptococcus and what would the results be

Answer 2

Staphylococcus is catalase positive and streptococcus is catalase negative

Question 3

what this

Answer 3

Staphylococcus

Question 4

what test is this and which is strep vs staph

Answer 4

Catalase test
Left: streptococcus (-)
Right: staphylococcus (+)

Question 5

Are staphylococcus commensal bacteria

Answer 5

Yes, but can become opportunistic pathogens when there is damage to skin or mucous membranes or in immunocompromised patients

Question 6

What test differentiates against staphylococcus species

Answer 6

Coagulase test

Question 7

What are the results of coagulase test for pathogenic vs non-pathogenic strains

Answer 7

Pathogenic strains positive, non-pathogenic strains negative

Question 8

What test is this and what does it tell you about staphylococcus spp

Answer 8

coagulase test
Left: positive- pathogenic strains of staphylococcus
Right: negative- non-pathogenic strains

Question 9

what test is this and what does it tell you about staphylococcus spp

Answer 9

Coagulase test
Left: negative- nonpathogenic strains of staphylococcus
Right: positive- pathogenic strains of staphylococcus

Question 10

Which species of staphylococcus is the only one that does do hemolysis

Answer 10

S. Hyicus

Question 11

What are adhesins

Answer 11

Cell wall proteins that bind fibrinogen and collage to facilitate bacterial attachment to host tissues

Question 12

What does protein A do

Answer 12

Surface protein that binds IgG by Fc and interferes with opsonization and phagocytosis

Question 13

What do alpha-toxins/ alpha-hemolysis do

Answer 13

Complete lysis of RBC’s, causes spasm of smooth muscle

Necrotizing and potentially lethal

Question 14

What is the major toxin in gangrenous mastitis

Answer 14

Alpha toxin/alpha-hemolysin

Question 15

What do beta-toxins/ beta hemolysin do

Answer 15

Incomplete/ partial lysis of RBC’s, damages cell membrane

Question 16

What do gamma-toxins/ leucocidin do

Answer 16

Cytolytic destruction of leukocytes

Question 17

What enterotoxins/ exotoxins are present in staphylococcus

Answer 17

Staphylococcus enterotoxin A-E and G-J; SEA-SEJ

Question 18

What is SEA-SEJ responsible for

Answer 18

Diarrhea and vomiting when ingested (food poisoning)

Super antigen binds MHC2 to T-cell receptor leading to massive T cell activation

Question 19

What superantigen is responsible for toxin shock syndrome when released into blood

Answer 19

Toxic shock syndrome toxin-1

Question 20

What are exfoliative toxins

Answer 20

Proteases that contribute to skin lesions

Question 21

What toxin is main virulence factor in S. Hyicus

Answer 21

Exfoliative toxins

Question 22

What does staphylokinase do

Answer 22

Breaks down blood clots

Question 23

What does hyluronidase do

Answer 23

Depolymerizes hyaluronic acid (CT) breaks open epithelial cells

Question 24

What does coagulase do

Answer 24

Converts fibrinogen to fibrin —> produces blood clots

Question 25

What is the purpose of a capsule

Answer 25

Protect bacterial cells from phagocytosis

Question 26

Which staph/ virulence factor raises pH in urine, forms urinary stones

Answer 26

S. Pseudointermedius urease

Question 27

What is the staph causative agent in contagious mastitis

Answer 27

S. Aureus

Question 28

What is the main source of infection in S. Aureus contagious mastitis

Answer 28

Colonize the teat skin, teat canal and udder

Question 29

What is the pathogens is of contagious mastitis in cattle

Answer 29

1. Adhesins facilitate bacterial attachment 2. Invasins facilitate tissue invasion 3. Capsule protect bacteria from phagocytosis by host cell 4. Leukocidin, hemolysins, exotoxins cause tissue damage

Question 30

What stage of lactation does acute and peracute contagious mastitis occur

Answer 30

Early lactation

Question 31

What are the clinical manifestations of acute and peracute contagious mastitis

Answer 31

Acute swelling of udder, purulent secretion

Question 32

What does peracute gangrenous cause in contagious mastitis

Answer 32

Venous thrombosis and congestion of the udder that lead to tissue necrosis

Question 33

What are the signs of peracute gangrenous contagious mastitis

Answer 33

Quarter is sore and swollen, fever, anorexia, lameness, toxemia may cause death

Question 34

What is the most common form of contagious mastitis in cattle

Answer 34

Chronic/subclinical

Question 35

What is elevated in chronic/subclinical mastitis

Answer 35

Somatic cell counts

Question 36

The inflammatory response in chronic/ subclinical mastitis results in what

Answer 36

Duct blockage and atrophy of associated alveoli

Question 37

Influx of phagocytic cells lead to ___ and limits __ in chronic/subclinical contagious mastitis

Answer 37

Abscess formation and fibrosis, limits antibiotic access (hard to tx)

Question 38

In chronic/subclinical mastitis there is gradual damage to ___ and drop in ___

Answer 38

Udder, milk yield

Question 39

How do you monitor contagious mastitis in cattle

Answer 39

CMT- measures somatic cells in milk

Question 40

What cell is high in mastitis

Answer 40

Leukocytes

Question 41

How does a CMT test work

Answer 41

Reagent reacts with leukocytes and will form gel with infection, the greater the gel the worse the infection

Question 42

How do you diagnose contagious mastitis in cattle

Answer 42

Culture results If culture is positive test individual causes of high SCC (>400k)

Question 43

What is the treatment for contagious mastitis in cattle

Answer 43

Intramammary (preferred), IM or IV antibiotics

Question 44

How do you prevent contagious mastitis

Answer 44

1. Milking equipment maintenance 2. Hygienic procedures 3. Milking order: healthy, first lactating, older cows first then subclinical mastitis last or separate 4.eliminate fly breeding sites 5. Culling- cows with persistent S. Aureus infection

Question 45

What vaccine is available to prevent contagious mastitis (staph aureus)

Answer 45

Lysigin

Question 46

The vaccine for contagious mastitis (s. Aureus) is only effective in who

Answer 46

Healthy young heifers

Question 47

Does the staph. Aureus contagious mastitis vaccine prevent infection

Answer 47

No lowers effect and milder diasease

Question 48

What is the causative agent in exudative epidermitis in pigs

Answer 48

Staphylococcus Hyicus

Question 49

What pigs are commonly affected by S. Hyicus

Answer 49

Up to 3 months old

Question 50

What is the pathogens is for exudative epidermitis in pigs

Answer 50

1. Enter the skin through minor abrasions or bite wounds 2. Adhesins, invasins, leukocidins, capsules, exotoxins (no hemoylsins) 3. Exfoliative toxins are main cause

Question 51

What is the clinical manifestation of exudative epidermitis in pigs

Answer 51

Excessive sebaceous secretions, exfoliation and exudation on skin, erosions of snout, foot pads, anorexia, depression, fever

Question 52

Exudative epidermitis in pigs is also called ___ disease

Answer 52

Greasy pig disease

Question 53

What pigs are affected in the acute form of exudative epidermitis

Answer 53

Suckling piglets- usually die within 48hrs

Question 54

What pigs are affected in chronic form of exudative epidermitis in pigs

Answer 54

Weaned pigs

Question 55

What is the morbidity and morality associated with exudative epidermitis in pigs

Answer 55

Morbidity: 20-100% Mortality: ~90% (low morality in adult pigs)

Question 56

How do you diagnose exudative epidermitis in pigs

Answer 56

1. Clinical presentation- skin lesions 2. Culture and antibiotic sensitivity

Question 57

Pig presents with skin lesions, histo shows a gram positive organism. It is also coagulase positive and non-hemolytic. What is likely cause

Answer 57

S. Hyicus

Question 58

What is treatment for exudative epidermitis in pigs

Answer 58

1. Early systemic antibiotic (7-10days) 2. Daily topical antiseptic 3. Drugs: amoxicillin, fluoroquinolones, ceftiofur, linomycin

Question 59

How can you control exudative epidermitis in pigs

Answer 59

1. Strict isolation of affected pigs 2. Cleaning and disinfection 3. Wash sows with antiseptic before farrowing

Question 60

Is there a vaccine for exudative epidermitis in pigs

Answer 60

Yes, but only shows some success in chronically infected herds

Question 61

What is the causative agent staph pyoderma in cats and dogs

Answer 61

S. Pseudointermedius

Question 62

Where does the superficial infection of S. Pseudointermedius infect

Answer 62

Epidermis and hair follicles

Question 63

Where does a deep dermis infection of S. Pseudointermedius result in

Answer 63

Furunculosis (boils)

Question 64

What is the pathogens is for S. Pseudointermedius causing pyoderma

Answer 64

1. Adhesins facilitate bacterial attachment 2. Invasins 3. Capsules prevent phagocytosis 4. Leukocidins, hemolysins, exotoxins

Question 65

What is the most important virulence factor for S. Pseudointermedius pyoderma

Answer 65

Adhesins most important for bacterial stickiness to keratinocytes

Question 66

What are the clinical manifestations of S. Pseudointermedius pyoderma in dogs

Answer 66

Multifocal areas of alopecia, follicular -apples, pustules, crusts

Question 67

What are the clinical manifestations of S. Pseudointermedius pyoderma in cats

Answer 67

Alopecia, ulcerations, hemorrhagic crusts, draining tracts

Question 68

How do you diagnose S. Pseudointermedius pyoderma in cats and dogs

Answer 68

1. Clinical signs- hair loss, papules, pustules 2. Bacterial culture and susceptibility testing

Question 69

Why is it important to test for sensitivity in S. Pseudointermedius pyoderma

Answer 69

To determine if methicillin resistant staphylococcus Pseudointermedius (MRSP)

Question 70

What is the treatment of pyoderma in cats and dogs

Answer 70

1. Narrow spectrum antibiotic for 30 days 2. Resolution for 7 days 3. Topical- mupirocin 4. Medicated shampoos

Question 71

What medicated shampoo is showing promising results for dogs with Staph pyoderma

Answer 71

Sodium hypochlorite and salicylic acid shampoo

Question 72

What is the gold standard for diagnosing staphylococcus infections

Answer 72

Culture

Question 73

What do you expect to see on microscopy with staph infections

Answer 73

Neutrophils containing gram positive staphylococcus

Question 74

What isolation medias can be used to dx staph

Answer 74

1. Blood agar 2. MacConkey- gram - so nothing happens 3. Mannitol salt agar- NaCl selects for staphylococcus 4. Purple agar- golden color with S. Aureus

Question 75

What agar can be used to identify S. Aureus from other staphs

Answer 75

Purple agar