Microbiology: Staphylococci, Streptococci, & Propionbacterium: Block Ii

Front 1

Gram positive cocci in pairs, short chains, and grape like clusters. Is a common bacteria that may be part of the normal flora:

Back 1

Staphylococci

Front 2

This is more than 90% of strains of staphylococci and has beta-hemolysis:

Back 2

S. aureus

Front 3

Staphylococci that is coagulase positive:

Back 3

S. Aureus

Front 4

Staphylococci that may be normal flora in the anterior nares, is transient on the skin surface, is responsibe for most staph disease and its resistance can be a big problem:

Back 4

S. Aureus

Front 5

This is a coagulase negative Staphylococci that is common as normal skin flora, may cause disease associated with foreign body colonization (shunts, catheters), leading to bacteremia and endocarditis

Back 5

S. epidermidis

Front 6

This coagulase negative staphylococci is common as normal skin flora and is an important cause of UTIs in young, sexually active females:

Back 6

S. saprophyticus

Front 7

This gram positive cocci can survive drying conditions on environmental surfaces which is important in transmission, particularly in hospitals.

Back 7

Staphylococci

Front 8

All streptococci are catalase ________, a reflection of their totally fermentative metabolism.

Back 8

Catalase negative

Front 9

Which test can help distinguish staph from strep?

Back 9

Catalase test- most staphylococci are catalase positive (aureus) and all strep are catalase negative.

Front 10

This type of staphylococci are pale yellow to orange colored:

Back 10

S. Aureus

Front 11

This is the major protein component of the cell wall of S. aureus and inhibits host phagocytic response by interfering with opsonization but is not the major virulence factor:

Back 11

Protein A

Front 12

Does S. Aureus have a capsule?

Back 12

Yes, its a polysaccharide polymer and is anti-phagocytic.

Front 13

This is the major exotoxin of S. Aureus, is a channel forming toxin with wide biologic activity and is the most important extracellular virulence factor.

Back 13

alpha-toxin

Front 14

This extracellular toxin produced by S. aureus kills and inhibits phagocytic cells causing tissue necrosis:

Back 14

Cytolytic toxin

Front 15

This is found in 2% of cases of S. aureus and is highly associated with CA-MRSA Panton-Valentine leucocidin (PVL) - two protein components with altered permeability to cations. It lysis WBCs and is found in community acquired disease:

Back 15

Leukocidin

Front 16

Responsible for staph food poisoning and triggers immediate vomiting reflex and is not reliably destroyed by boiling.

Back 16

Enterotoxins

Front 17

This exotoxin produced by S. aureus acts as a superantigen and potent inducer of TNF and IL-1 causing systemic inflammation

Back 17

Toxic Shock Syndrome Toxin 1

Front 18

This exotoxin secreted from S. aureus causes scalded skin syndrome

Back 18

Exfoliative toxin

Front 19

This superantigen binds non-specifically to T cells causing systemic inflammation

Back 19

TSS T-1

Front 20

Where does S. aureus live?

Back 20

In the anterior nares in 25-30% of normal individuals. It is also transient on the skin surface where it is a risk for transmission.

Front 21

Can cause cutaneous infection with folliculitis, boils, and wound infections with extreme inflammation, pain and purulent exudate. May also disseminate to the bloodstream .

Back 21

S. aureus

Front 22

Causes impetigo

Back 22

S. aureus

Front 23

This is a local infection with systemic toxemia with sloughing of skin caused by exfoliative toxin:

Back 23

Scalded skin syndrome

Front 24

This is a local infection with systemic toxemia which can cause hypotension leading to cardiac arrest and heart failure. Systemic toxemia due to TSS T-1

Back 24

Toxic Shock Syndrome

Front 25

What bacteria causes scalded skin syndrome and toxic shock?

Back 25

S. aureus

Front 26

This is caused by ingestion of preformed toxin by S. aureus and has rapid onset of symptoms (2-6hr)

Back 26

Food poisoning

Front 27

This causes more serious and invasive pneumonia usually in children less than 1 year old or immunocompromised people and can lead to consolidation or necrosis with formation of multiple abcesses.

Back 27

S. Aureus

Front 28

Is the most frequent organism causing osteomyelitis and caused by hematogenous spread from wound or boil or direct spread from tissue puncture wound penetrating the bone.

Back 28

S. aureus

Front 29

Seen in 50% of all cases of bacterial arthritis.

Back 29

S. aureus

Front 30

This pathogen should always be suspected with endocarditis, half of cases are hospital acquired from bacteremia follwoing primary infection of the skin, URT, or other site.

Back 30

S. Aureus

Front 31

Presents as mitral and aortic valvular problems, splinter hemorrhanges, janeway lesions and can be seen in tricuspid valve in IV drug users

Back 31

Endocarditis - caused by S. aureus

Front 32

Meningitis and brain abcesses caused by this bacteria are most commonly seen as direct spread from the nasal cavity to the brain from head trauma or sinus trauma.

Back 32

S. Aureus

Front 33

How is S. aureus infection diagnosed?

Back 33

By direct exam of a gram stain from a sterile site (only) - can also be cultured and seen as catalase positive with coagulase

Front 34

Why would we want to culture S. aureus from a patient?

Back 34

To determine antibiotic sensitivities - MRSA ID and molecular typing

Front 35

How is S. aureus prevented?

Back 35

There is no vaccine so proper hand washing

Front 36

Why would you want to know if S. aureus is hospital or community acquired?

Back 36

Because the treatment is different.

Front 37

Is the major streptococci pathogen, is never considered normal flora and causes respiratory, skin/tissse, and blood infections.

Back 37

Group A (S. pyogenes)

Front 38

This group of streptococcus are normal flora in the intestines and sometime have secondary spread to the vagina. Causes soft tissue infections and is the major cause of neonatal meningitis with transmission during birth.

Back 38

Group B Streptococci agalactinae

Front 39

Which group of streptococci involves a screen of pregnant wormen with an antigen detection kit (vaginal swab)?

Back 39

Group B Strep agalactinae

Front 40

This group of streptococci is normal flora of the intestines, vagina, URT and skin. It is a nosocomial problem from contamination of the hospital environment, is a major cause of UTIs, and has increasing vancomycin resistance:

Back 40

Group D Enterococcus species

Front 41

This alpha hemolytic streptococci is normal flora of the URT, is a common cause of pneumonia, meningitis, otitis media and sinusitis.

Back 41

S. pneumoniae

Front 42

This alpha hemolytic streptococci are normal flora in the oral cavityand URT with some also seen in the female genital tract. It can enter the bloodstream after dental manipulations or other oral trauma and can cause infections and abcesses in many areas of the body.

Back 42

Viridans group

Front 43

This is the major virulence factor and major antigen of S. pyogenes

Back 43

M protein

Front 44

This fibrillar molecule is composed of two a-helocal chains, inhibits complement fixation, resistant to phagocytosis and is the major virulence factor for S. pyogenes

Back 44

M protein

Front 45

What role does the capsule play in Strep pyogenes?

Back 45

It is antiphagocytic but it less important than M protein

Front 46

What are the cytolytic toxins of S. pyogenes that are responsible for killing phagocytic cells and tissue necrosis?

Back 46

Streptolysin O and S

Front 47

These fever producing toxins are found in Strep pyogenes:

Back 47

Pyrogenic exotoxins

Front 48

What are the pyrogenic exotoxins of Step pyogenes that ar superantigens and highly inflammatory? They are also associated with scarlet fever and TSS.

Back 48

SpeA and SpeC

Front 49

Which pyrogenic exotoxin is associated with the most severe disease?

Back 49

SpeA

Front 50

Hyaluronidase, steptokinase (fibrinolysin), and C5a peptidase are all _________ produced by S. pyogenes.

Back 50

Exo-enzymes

Front 51

Where is S. pyogenes considered normal flora?

Back 51

It is not considered normal floral even though everyone colonzied doesn't get disease. It colonizes the respiratory tract and other mucosal surfaces and is transient on the skin.

Front 52

How is Strep pyogenes transmitted?

Back 52

Person to person through touching of the skin and carrying it on hands. Also through repiratory droplets or exchanging secretions.

Front 53

This kind of strep causes URT and skin infections primarily in children from 5-15

Back 53

S. pyogenes

Front 54

This pathogen causes pharngitis, scarlet fever, and pneumonia:

Back 54

S. pyogenes

Front 55

Encrusted pustules on superficial layers of skin often seen as a co-infection with staphylococci and often associated with certain M protein serotypes

Back 55

Impertigo (pyoderma)

Front 56

Most superficial skin/soft tissue infection, can be caused by staph, strep or both.

Back 56

Impetigo

Front 57

Acute lymphangitis of the skin that may be a complication of untreated impetigo. It is iflammation of lymphatic vessels with red, sharp margins that is most often seen in the face and lower extremities. Is caused by S. pyogenes

Back 57

Erysiplas

Front 58

Flesh eating streptococci

Back 58

Necrotizing fasciitis - usually caused by group A strep or MRSA

Front 59

Bacteria enter through a break in the skin (minor trauma) and follow a path along the fascia between the subcutaneous tissue and the muscle, the skin dies and the muscle may be infected. Causes bacteremia, and streptococcal toxic shock syndrome

Back 59

Necrotizing fasciitis

Front 60

Complication of bacteremia or agressive soft tissue infection associated with systemic production of pyrogenic exotoxins. The blood culture will be positive because the pyrogenic exotoxin is combined wih bacteremia from deeper infection.

Back 60

Streptococcal toxic shock syndrome

Front 61

This disease is seen after a group A strep pharyngeal infection but not after a skin infection

Back 61

Rheumatic fever

Front 62

Inflammatory reaction seen after a Group A strep skin or pharyngeal infection with deposition of immune complexes in the kidney two to three weeks following a skin infection.

Back 62

Acute glomerulonephritis (AGN)

Front 63

How is strep diagnosed?

Back 63

1. Direct examination of a gram stain from a sterile site
2. Culture on blood agar
3. Serology for ASO, or anti-DNAse B
*Don't use antigen detection kits

Front 64

How is streptococci treated?

Back 64

With penicillin- nearly all strains are sensitive and so no need for antibiotic testing. Invasive disease is treated with clinda or erythromycin

Front 65

This pathogen is typically resistan to TMP-SMX (bactrim) so it would not be covered by some treatments for community acquired MRSA.

Back 65

Streptococcus pyogenes

Front 66

How is streptococcus prevented?

Back 66

With prompt therapeutic intervention to prevent sequelae. There is no vaccine

Front 67

Group of gram positive rod-shaped bacteria that are related to Corynebacterium but are anaerobic and non-toxic.

Back 67

Propionibacterium

Front 68

Most species are normal inhabitants of the skin living harmlessly in the anerobic areas of the hair follicles

Back 68

Propionibacterium

Front 69

The most recognized species of Propionibacterium that causes inflammation of the hair follicle and sebaceous glands related to the over-production of lipids in sebum

Back 69

Propionbacterium acnes

Front 70

This gram positive rod looks like chinese characters, are obligate anaerobes and produce lipases to degrade lipids for nutrients.

Back 70

P. acnes

Front 71

How is P. acnes transmitted?

Back 71

It is normal flora of the skin but acne occurs as overgrowth in response to nutrient stimulation (lipids)

Front 72

Causes an intense local inflammatory response without spread into tissues or the bloodstream and forms papules, pustules, and nodulocystic lesions typical of the disease.

Back 72

P. acnes (causes Acne vulgaris)