.microbio E1: Staph, Strep, And Other Gram Positives

Front 1

What are all staphylococci with regards to:
A. gram staining
B. morphology
C. catalase test

Back 1

Staphylococci are all...
A. gram positive
B. cocci in clusters (grapes, since divides in two planes)
C. catalase POSITIVE (strep is catalase negative)

Front 2

True or False:
Streptococci are catalase positive.

Back 2

FALSE.

Staphylococci are catalase positive ; streptococci are catalase negative.

Front 3

What definitively differentiates Staphylococci aureus from all other Staph?

A. Agglutination test
B. Catalase test
C. Coagulase test
D. Novobiocin resistance

Back 3

C. Coagulase test - only Staphylococci aureus is coagulase POSITIVE

Agglutination test is also a good way since only S.aureus is agglutination positive but not all S.aureus is so. All staphylococci are catalase positive. Novobiocin resistance is only conferred to S.saprophyticus, not S.aureus.

Other things special to S.aureus are: + clulmping factor, protein A, hemolysis, yellow pigment, and ribitol teichoic acid.

Front 4

_________ is found in the nares and throat of 30-50% of healthy adults and can also be found on skin in moist areas (between toes, armpits).

A. S. aureus
B. S. epidermidis
C. S. saprophyticus

Back 4

A. S. aureus

note: S.aureus can't usually withstand the dryness and saltiness that S.epidermidis can so S.aureus is not normally found distributed on skin - only on moist skin!

Front 5

____________ attract neutrophils (PMNs) and lead to pus formation. Neutrophils and opsonophagocytosis are the most important defenses against this bacteria.

A. Bacillus
B. Enterococcus
C. Listeria
D. Staphylococci
E. Streptococci

Back 5

D. Staphylococci

Staphylococci is thus said to be "pyogenic" or "suppurative".

Front 6

True or False:
Neutrophil dysfunctions can lead to increased Staphylococci infections.

Back 6

TRUE.
Hypo or agammaglobulinemia (low or no antibodies), Job's syndrome (Hyper-IgE), chronic granulomatous disease, Chediak-Higashi syndrome, diabetes

Front 7

What are the four classes of virulence factors of S.aureus?

Back 7

1. Cell envelope associated factors (peptidoglycan, capsular polysaccharide, **PIA**, Teichoic acid)
2. Surface proteins (associated with aureus only: **Protein A**, **clumping factor**, MSCRAMMs-adhesive matrix molecules, **catalase**)
3. Exoenzymes (proteases, nucleases, lipases, staphylokinase, **catalase**)
4. Toxins (**superantigen toxins --> massive cytokine release = TSST1, staphylococcal enterotoxins, exfoliatin**)

Front 8

The characteristic pathologic lesion caused by _____________ is an abcess.

A. Bacillus
B. Enterococcus
C. Listeria
D. Staphylococci
E. Streptococci

Back 8

D. Staphylococci

The abcess is a focal area that is well-demarcated and consists of a central area of necrosis containing liquefied tissue, lysed PMNs, proteinaceous debris and bacteria. It is surrounded by a zone of intact PMNs that are phagocytosing bacteria and the entire area is walled off by a layer of fibrin.

Front 9

True or False:
S.epidermidis does not produce a capsule, but produces more PIA (polysaccharide intercellular adhesin) and is generally a better biofilm producer than S.aureus.

Back 9

True!

Biofilm formation is considered the major virulence factor of epidermidis because it results in the biofilm formation on catheters.

Front 10

What is polysaccharid eintercellular adhesin (PIA) important for?

Back 10

It is a virulence factor of S.aureus. Specifically,a cell envelope associated factor.

Front 11

What do the following S.aureus virulence factors do?

A. Catalase
B. Coagulase
C. PIA (polysaccharide intercellular adhesin)
D. Protein A

Back 11

A. Catalase: breaks down hydrogen peroxide to water and oxygen, thus interfering with oxidative killing by PMN inside phagocytic vacuole
B. Coagulase : converts fibrinogen to fibrin and prevents PMN access to the developing abscess by creating a wall of fibrin around the infection. Is diagnostic marker for S.aureus!
C. PIA (polysaccharide intercellular adhesin): plays a role in biofilm formation
D. Protein A: binds Fc fragment of IgG subclasses and orients the antibody in the wrong direction, thus preventing opsonization.

Front 12

S.aureus toxins fall under two categories: superantigen toxins and pore-forming toxins.

Describe/detail each.

Back 12

Superantigen toxins: Causes shock by massive release of cytokines IL-1 and TNF alpha. --> Toxic shock syndrome toxin. Staphylococcal Enterotoxins. Exfoliatin.

Pore-forming toxins: Subunits assemble to form rings that form pores in membranes of human cells. Alpha toxin. Panton-Valentine Leukocidin (PVL).

Front 13

[ Group A strep / S.aureus ] is the most common cause of pyogenic skin infections although in general [ Group A strep / S.aureus ] is a more common cause of "spreading" infections like cellultis, necrotizing fasciitis, and impetigo.

Back 13

S.aureus.....Group A strep

Front 14

Match the description to the term. Bullous impetigo, Carbuncle, Cellulitis, Folliculitis, Furuncle

A. epithelial abscess
B. group of interconnected furuncles
C. inflamed hair follicle
D. characterized by crusty, pustular blisters

Back 14

A. Furuncle = epithelial abscess
B. Carbuncle = group of interconnected furuncles
C. folliculitis = inflamed hair follicle
D. Bullous impetigo is crusty pustular blisters

Front 15

_________ is the most common cause of osteomyelitis and septic arthritis.

A. S. aureus
B. S. epidermidis
C. S. saprophyticus

Back 15

A. S. aureus

This is the metastatic infection of the bone and joint kind. Collagen binding protein (a MSCRAMM) is involve din colonization of bone.

Front 16

___________ is the most common cause of endocarditis in IV drug abusers and acute endocarditis.

A. S. aureus
B. S. epidermidis
C. S. saprophyticus

Back 16

A. S. aureus

Also most common cause of osteomyelitis, septic arthritis, epidural abscess, pyomyositis, food poisoning.

Front 17

True or False:
Toxinosis is a syndrome caused only by the action of a toxin without bacterial invasion.

Back 17

True.

The three S.aureus toxinoses are: Toxic Shock syndrome, Scalded skin syndrome, food poisoning.

Front 18

What is the DOC for methicillin-resistant staphylococci?

Back 18

Vancomycin

Front 19

What are the coagulase negative staphylococcal infections and what conditions are they associated with?

Back 19

S.epidermidis: typically only cause infection in association with a foreign device (IV catheters, artificial heart valves and joints, breast implants and pacemakers.
S.saprophyticus: second leading cause of UTI's in young, sexually active females (first is E.coli)

Front 20

How is S.aureus, S.epidermidis, and S.saprophyticus differentiated from one another?

Back 20

All are catalase positive and ferment glucose. S.aureus additionally ferments mannitol, is coagulase, agglutination clumping, protein A, hemolysis, yellow pigment and ribitol teichoic acid positive. S. epidermidis is differentiated from S. sapropyticus becuase S. saprophyticus is novobiocin resistant whereas S.epidermidis is not.

Front 21

Give examples of each virulence factor category listed below.
1. Cell envelope associated factor
2. Surface proteins
3. Exoenzymes
4. Toxins

Back 21

1. Peptidoglycan, capsular polysaccharide, **polysaccharide intercellular adhesin**
2. **Protein A** (binds to Fc fragment of IgG subclasses, which orients the antibody in the wrong direction and prevents opsonization, **clumping factor**, MSCRAMMs, **coagulase**
3. Proteases, nucleases, lipase, hyaluronate lyase, staphylokinase, **catalase**
4. **superantigen toxins - Toxic shock syndrome toxin, staphylococcal enterotoxins, exfoliatin. pore-forming toxins- alpha toxin, panton-valentine leukocidin (VPL)**.

Front 22

What is the difference between staphylococcal alpha toxin and Panton-Valentine Leukocidin (PVL)?

Back 22

Though both are pore-forming toxins (rather than superantigen toxins, the other toxin type associated with staphylococci), alpha toxin is a acritical virulence factor in pneumonia whereas leukocidin lyses PMNs in particular.

Front 23

________ is a syndrome caused ONLY by the action of a toxin WITHOUT BACTERIAL INVASION. There are three of these for S.aureus. What are they?

Back 23

Toxinosis.
1. Toxic shock syndrome (TSS): TSST-1 or an enterotoxin gains access to the blood from vagina, wound infection or upper airway colonization and causes fever, hypotension, sunburn like rash, peeling of skin of palsma dn soles and involvement of other organs (kidney, liver, blood cells).
2. Scalded Skin Syndrome: if in neonates, causes entire superficial skin layer to peel offf all over body. If in adults, causes blisters to form in isolated areas.
3. Food poisoning: S.aureus is salt tolerant and can grow on salty foods. The toxin is heat-stable, so persists even if food is cooked. Ingestion results in vomiting within a short incubation period (2-8hours).

Front 24

The major class of antibiotics used to treat staphylococcal infections is________.

Back 24

beta-lactams.

Many staphylococci are resistant to penicillin. DOC for MRSA is vancomycin. Daptomycin can slo be used.

Front 25

The DOC for MRSA (methicillin-resistant stpahylococci) is....

Back 25

vancomycin. Daptomycin can also be used.

Front 26

Resistance to beta-lactam antibiotics (penicillin and its relatives) is an important type of resistance S.aureus can acquire. What can resistance be due to? (3 mechs)

Back 26

1. beta-lactamase production (enzyme that destroys the antibiotic)
2. Syntehsis of a new target resistant to antibiotic inhibition.
3. Glycopeptide resistance. Strains that overproduce peptidoglycan thus exhibit some resistance to glycopeptides (vancomycin is a major one). Within past few years, some vancomycin resistance has occurred.

Front 27

This staphylococal infection typically is associated with foreign device placement in the body. What is its major virulence factor?

Back 27

Staphylococcus epidermidis. Most common cause of infections of IV catheters, artificial heart valves and joints, breaest implants and pacemakers. They are usually resistant to multiple antibiotics and cause indolent infections. Their major virulence factor is the PIA (polysaccharide intercellular adhesin) which allos them to have biofilm properties.

Front 28

This staphylococcal infection is the second leading cause of UTI's in young, sexually active females.

Back 28

S. saprohpyticus. Second to E.coli.

Front 29

_________ are chains of Gram-positive cocci.

A. Staphylococci
B. Streptococci

Back 29

B. Streptococci

Front 30

Regarding differentiation by hemolysis on blood agar, describe beta, alpha and gamma hemolysis. Categorize the following species into their respective categories:
Enterococcus, S. agalactiae, S.pneumoniae, S.pyogenes, S.viridans.

Back 30

Beta = total hemolysis. Group A S.pyogenes and Group B S.agalactiae.
Alpha = partial hemolysis, green. S.pneumoniae, S.viridans
Gamma = no hemolysis. Enterococcus

Front 31

Why is C substance important for Streptococci identification?

Back 31

Cell wall carbohydrate C substance's antigenic reactivity is how Lancefield Typing is determined. Lancefield Typing is a way of grouping Streptococci.
Group A = S. pyogenes
Group B = S.alalactiae
Group D = Enterococcus

Front 32

Only ________ exhibits bacitracin sensitivity.

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 32

D. S.pyogenes (Group A strep)

Front 33

What organism is included in Group A strep and what is the diffrentiating test for it?

Back 33

Streptococcus pyogenes. It is the only one sensitive to bacitracin.

Front 34

What is the CAMP test and which listed can be differentiated from the others by this test?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 34

CAMP test is streaking known S.aureus on a plate then streaking your unknown strep. If that unknown strep is Strep agalactiae (Group B), then hemolysins from both act synergistically and produce arrowhead type hemolysis at their perpendiculars.

B. S. agalactiae

Front 35

What is the Esculin test and which listed can be differentiated from the others by this test?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 35

Liquid or solid media containing bile esculin turns black with Group D strep, or Enterococcus.

A. Enterococcus

Front 36

Only ________ exhibits optochin sensitivity.

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 36

C. S.pneumoniae

Optochin sensitivity is a good test to differentiate between the alpha-hemolytic strep.

Front 37

Which of the following would produce partial hemolysis and grow in the presence of bacitracin and optochin?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 37

E. S.viridans

Really all you need to know for S.viridans is that it is alpha-hemolytic and optochin resistant. Alpha-hemolsis narrows it down to S.pneumoniae and S.viridans. Optochin resistance pinpoints it as S.viridans because S.pneumoniae is optochin-sensitive. The bacitracin was just a distractor as that's really only used to differentiate S.pyogenes from all other strep.

Front 38

Name the organisms that are nested under each type of hemolysis and which tests you can utilize to differentiate between each within the hemolytic group.

Back 38

Beta hemolysis= S.pyogenes or S. agalactiae. S.pyogenes has bacitracin sensitivity whereas S.agalactiae has positive CAMP test.
Alpha hemolysis= S. pneumoniae or S.viridans. S.pneumoniae is positive for both optochin sensitivity and Quellung reaction.
Gamma hemolysis = Enterococcus. Confirm with positive Esculin test.

Front 39

Which exhibits complete hemolytic clearing, and is not sensitivty to bacitracin?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 39

B. S. agalactiae

This also yields a positive CAMP test.

Front 40

Which exhibits complete hemolytic clearing, and a positive CAMP test?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 40

B. S. agalactiae

Front 41

Which exhibits complete hemolytic clearing, and is sensitive to bacitracin?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 41

D. S.pyogenes

Front 42

Which exhibits partial hemolytic clearing, is not Optochin sensitive, and exhibits a negative Quellung reaction?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 42

E. S.viridans

S.pneumoniae is the other alpha hemolytic organism but it is positive for both the things S.viridans is negative.

Front 43

Which exhibits partial hemolytic clearing, is Optochin sensitive, and exhibits a positive Quellung reaction?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 43

C. S.pneumoniae

S.viridans is the other alpha hemolytic organism but it is negative for both the things S.pneumoniae is positive.

Front 44

Which exhibits no hemolytic clearing?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 44

A. Enterococcus

It also exhibits a positive Esculin test.

Front 45

Which exhibits a positive Esculin test?

A. Enterococcus
B. S. agalactiae
C. S.pneumoniae
D. S.pyogenes
E. S.viridans

Back 45

A. Enterococcus

It also exhibits gamma hemolysis (no hemolysis).

Front 46

True or False:
Main reservoir is humans for Group A streptococci (S.pyogenes). 10% may be asymptomatically colonized but spread is generally via symptomatic individuals (unlike Staph).

Back 46

True!

Transmitted by respiratory route or by direct contact with broken skin or mucosa. Can also be transferred by fomites.

Front 47

Virulence factors of S. pyogenes include: enzymes, hemolysins, hyaluronic capsule, M protein and Streptococcal pyrogenic exotoxins. Which is MOST important? Describe each a little.

Back 47

Most important is M protein! M protein binds fibrin and ilicits a STRONG antibody response. Is involved in rheumatic fever.
Pyrogenic exotoxins include superantigens and are responsible for scarlet fever, streptococcal toxinc shock syndrome and necrotizing fasciitis.
Enzymes like hyaluronidase, streptodornase (a DNAse) and SpeB (a protease), help Group A Strep spread better through tissues than Staphylococci infections.
Hemolysins - are important because they lead to the diagnostic hemolysis on blood agar.
Lastly, hyaluronic capsule just helps it look like host so it is antiantigenetic.

Front 48

What are some diseases caused by Group A strep?
1. Skin infections like....
2. Mucosal infections
3. Toxinoses
4. Invasive infections
5. Post-strep syndromes

Back 48

1. Skin infections like: impetigo, cellulitis, erysipelas (rapidly spreading sellulitis, severe systemic toxicity), necrotizing fasciitis
2. Mucosal infections - bacterial pharyngitis, otitis media, pneumonia
3. Toxinoses: Scarlet fever, Strep toxic shock syndrome
4. Invasive Infections: Sepsis, puerperal fever, can sometimes also cause meningitis and endocarditis
5. Post-strep syndromes: Acute rheumatic fever (occurs 1-2 weeks after Group A strep pharyngitis), acute post-strep glomerulonephritis (can occur after Strep skin infection)

Front 49

True or False:

Erysipelas spreads through subcutaneous and submucosal tissue. Cellulitis is more superficial, rapidly progressing and has well-demarcated margins.

Back 49

FALSE. They should be switched in description! Cellulitis spreads through submucosal and subcutaneous tissue!

Front 50

________ is the leading bacterial cause of pharyngitis.

A. Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus agalactiae
D. Streptococcus pyogenes
E. Streptococcus virdians

Back 50

D. Streptococcus pyogenes (Group A Strep)

Leading cause of pharyngitis in general is usually viral in origin but of the ones caused by bacteira, Group A strep is your culprit. Other mucosal infections caused by Group A strep is otitis media, pneumonia

Front 51

What are the two toxinoses associated with S.pyogenes (Group A Strep)?

A. Scarlet fever and Streptococcal toxic shock syndrome
B. Rheumatic fever and Streptococcal toxic shock syndrome
C.Puerperal fever and Meningitis
D. Acute rheumatic fever and Meningitis

Back 51

A. Scarlet fever and Streptococcal toxic shock syndrome

Scarlet fever - Erythrogenic toxin causes sandpaper-like rash on the body. Rash blanches under pressure. “Strawberry tongue” present.

Acute rheumatic fever is associated with post-strep syndromes. Puerperal fever and meningitis is associated with invasive infections.

Front 52

True or False:

Staphylococcal Toxic Shock Syndrome is associated with Scarlet fever in children and bacteremia.

Back 52

FALSE. Scarlet fever in children and bacteremia is associated with Streptococcal Toxic Shock Syndrome.

Front 53

What are the two post-strep syndromes caused by Group A Strep?

Back 53

Acute rheumatic fever and acute post-streptococcal glomerulonephritis.

Acute rheumatic fever occurs two weeks or more after initial Group A strep pharyngitis; does NOT occur after a skin infection (whereas glomerulonephritis can occur after skin infection). Is caused by antibody cross-reacting with strep. antigens and human tissue. Diagnosed using modified Jones criteria. Acute post-strep glomerulonephritis is caused by deposition fo antibody-antigen complexes in the kidneys.

Front 54

True or False:
Streptococci don't really become penicillin resistant.

Back 54

TRUE. Penicillin is DOC for strep.

Front 55

___________ is characterized by diplococci morphology and gram positive stain.

A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus pneumoniae
D. Streptococcus viridans
E. Enterococcus

Back 55

C. Streptococcus pneumoniae

Is the most common cause of community acquired pneumonia, bacterial meningitis, and otitis media.

Front 56

Which of the following is NOT most commonly caused by Streptococcus pneumoniae?

A. bacterial pharyngitis
B. bacterial menigitis
C. community=acquired pneumonia
D. otitis media

Back 56

A. bacterial pharyngitis

This is most commonly caused by Group A (Strep. pyogenes) strep.

Front 57

The major virulence factor for S.pneumoniae is [ antiphagocytic polysaccharide capsule / M protein ] ; the major virulence factor for S.pyogenes is [ antiphagocytic polysaccharide capsule / M protein ].

Back 57

S.pneumoniae = antiphagocytic polysaccharide capsule
S.pyogenes = M Protein

note: the antiphagocytic capsule is also the major virulence factor for S.agalactiae (Group B strep).

Front 58

What are the two most common complications of pneumonia cause by S.pneumoniae?

Back 58

Bacteremia and meningitis.

Front 59

________ is the most common cause of life-threatening infections of meningitis and pneumonia in neonates and is the normal flora in the genitourinary tract of 5-40% of women.

A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus pneumoniae
D. Streptococcus viridans
E. Enterococcus

Back 59

B. Streptococcus agalactiae

Front 60

Antiphagocytic capsule is a major virulence factor for which of the following?

A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus pneumoniae
D. Streptococcus viridans
E. Enterococcus

Back 60

B. Streptococcus agalactiae
C. Streptococcus pneumoniae

BOTH of em!

Front 61

Besides a positive _______ test, hippurate hydrolysis and latex agglutination for Group B Ag identifies an organism as S.agalactiae (Group B strep).

Back 61

positive CAMP test

Front 62

This organism is mainly found in the oral cavity.

A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus pneumoniae
D. Streptococcus viridans
E. Enterococcus

Back 62

D. Streptococcus viridans

Infective endocarditis can follow bacteremia from bleeding gums!!

Front 63

This organism is responsible for infective endocarditis, nosocomial infections and resistant to many antibiotics.

Back 63

E. Enterococcus

Front 64

True or False:
Enterococcus is part of the normal flora of the GI tract.

Back 64

True.

Front 65

How are enterococci infections treated and prevented?

Back 65

Treated with combination therapy since it is often resistant to most antibiotics including vancomycin. Prevention can focus on hospital infection control.

Front 66

Which streptococci has nearly widespread antibiotic resistance?

A. Strep pyogenes (Group A)
B. Strep agalactiae (Group B)
C. Enterococci
D. Pneumococcus

Back 66

C. Enterococci

Treated with combination therapy since it is often resistant to most antibiotics including vancomycin.

Front 67

Which streptococci has an immunization available for it?

A. Strep pyogenes (Group A)
B. Strep agalactiae (Group B)
C. Enterococci
D. Pneumococcus

Back 67

D. Pneumococcus

Front 68

List the virulence factor for each Strep species.

1. S.pyogenes (Group A)
2. S.agalactiae (Group B)
3. S. pneumoniae
4. S. viridans
5. Enterococcus

Back 68

1. S.pyogenes: M protein
2. and 3. S.agalctiae and S.pneumoniae: anti-phagocytic capsular polysaccharide
4. S. viridan and 5. Enterococcus : no major virulence factors

Front 69

Which causes strep throat, soft tissue infections, streptococcal TSS, rheymatic fever, and glomerulonephritis?

A. S.pyogenes (Group A)
B. S.agalactiae (Group B)
C. S. pneumoniae
D. S. viridans
E. Enterococcus

Back 69

A. S.pyogenes (Group A)

Front 70

Which commonly causes meningitis and otitis media?

A. S.pyogenes (Group A)
B. S.agalactiae (Group B)
C. S. pneumoniae
D. S. viridans
E. Enterococcus

Back 70

C. S. pneumoniae

This also causes community acquired pneumonia.

Front 71

What commonly causes neonatal meningitis?

A. S.pyogenes (Group A)
B. S.agalactiae (Group B)
C. S. pneumoniae
D. S. viridans
E. Enterococcus

Back 71

B. S.agalactiae (Group B)

Front 72

What commonly causes dental caries and endocarditis?

A. S.pyogenes (Group A)
B. S.agalactiae (Group B)
C. S. pneumoniae
D. S. viridans
E. Enterococcus

Back 72

D. S. viridans

Front 73

Which commonly causes endocarditis, UTIs, and ounwd infections?

A. S.pyogenes (Group A)
B. S.agalactiae (Group B)
C. S. pneumoniae
D. S. viridans
E. Enterococcus

Back 73

E. Enterococcus

Front 74

True or False:
Cutaneous infection with S.pyogenes (Group A strep) predisposes the infected individual to rheumatic fever.

Back 74

FALSE!!
Cutaneous infection with Group A strep does NOT lead to rheumatic fever. Though impetigo IS an important antecedent for streptococcal glomerulonephritis.

Front 75

_________, as opposed to ________, is localized, pustualr, crusty skin lesion that occurs in both sporadic and epidemic form among children.

Back 75

Impetigo, as opposed to cellulitis

Front 76

_________ is the most common prelude to scarlet fever, acute rheumatic fever and acute poststreptococal glomerulonephritis whereas ______ is the most common prelude to glomerulonephritis only.

Back 76

Pharyngitis to scarlet fever, acute rheumatic fever, acute poststrep glomerulonephritis ; Impetigo to glomerulonephritis.

Front 77

_________ is the most common cause of toxic shock.

A. Staph aureus
B. Strep pyogenes

Back 77

B. Strep pyogenes

Front 78

Name and describe the two post-streptococcal syndromes of S.pyogenes.

Back 78

Acute rheumatic fever and acute glomerulneophritis. ARF is inflammation in joints, heart, skin and CNS due to an autoimmune disease with antibody against Strep antigens cross- reacting with human tissues. It is very rare due to quick and effective antibiotic treatment of Group A strep. Acute pos-strep glomerulonephrtis can occur after strep pharyngitis OR skin infection. Renal lesions due to deposition of antibody and complement in glomerular capillaries.

Front 79

Unlike staphylococcus, ___________ does not make catalase and must therefore avoid being phagocytosed. Thus, capsule production is very important.

Back 79

Streptococcus

Front 80

This organism is also known as diplococcus.

Back 80

Streptococcus pnemoniae. Because it occurs in tissue in pairs.

Front 81

Which of the following three conditions does S.pneumoniae commonly cause?

A. adult bacterial meningitis
B. neonatal bacterial meningitis
C. otitis media
D. pharyngitis
E. pneumonia
F. scarlet fever

Back 81

A. adult bacterial meningitis
C. otitis media
E. pneumonia

Front 82

Patients at particular risk for serious pneumococcal infection are those that...

A. have impaired antibody production or bacterial clearance
B.have impaired neutrophil activity and production

Back 82

A. have impaired antibody production or bacterial clearance

Front 83

What kind of streptococi are carried asymptomatically in the genital and gastrointestinal tract of 5-40% of pregnant women?

Back 83

Streptococcus agalactiae (Group B strep)

Front 84

Which species iof enterococci causes the most infections? Which has become prevalent in hospitals and why?

A. Enterococcus faecalis
B. Enterococcus faecium
C. Enterococcus durans

Back 84

Most infections: A. Enterococcus faecalis

Most prevalent in hospitals: B. Enterococcus faecium because it has become resistant to vancomycin and most othe rantibiotics (is called VREF)

Front 85

Major enterococcal infections include.... (4, think general)

Back 85

1. Infective endocarditis
2. Nosocomial infections
3. UTIs
4. Wound infections

Group D strep are normal inhabitants of the human GI tract (normal flora) and are of low virulence.

Front 86

Enterococci differ from streptococci in that they are resistant to....

Back 86

the bactericidal activity of beta-lactam antibiotics.

Front 87

What is the only medically important nonenterococcal Group D streptococcus?

Back 87

Streptococcus bovis. Streptococcus bovis can cause bacteremia and enters the bloodstream through the GI tract. It is an indicator of colon cancer so patients with S. bovis bacteremia will always get a colonoscopy.

Front 88

True or False:
While resistance of all Streptococcus pyogenes (Group A strep) to erythromycin is increasing, all remain susceptible to penicillin G.

Back 88

True

Front 89

Enterococci are inhibited, but no killed, by penicillin G, ampicillin and vancomycin. They are intrinsically resistant to most of the other antibacterial agents. So hwo are they killed?

Back 89

Need to have one of the three mentioned antibiotics (penicililn G, ampicillin or vancomycin) PLUS an aminoglycoside. Some strains are unfortunately still resistant to even those and these are called vancomycin-resistant enterococci, or VREF.

Front 90

_______ is mainly a disease of herbivores. Human disease primarily arises from contact with infected animals or animal products.

A. Bascillus anthracis
B. Bascillus cereus
C. Listeria monocytogenes
D. Corynebacterium diptheriae

Back 90

A. Bascillus anthracis

Front 91

This is normally found in soil, but also can be found in foods such as rice and beans. Thus, can be causative agent in food poisoning ( a short emetic form and long diarrheal form).

A. Bascillus anthracis
B. Bascillus cereus
C. Listeria monocytogenes
D. Corynebacterium diptheriae

Back 91

B. Bascillus cereus

Front 92

What two conditions can Bascillus cereus be responsible for?

Back 92

Food poisoning (short incubated emetic form or long incubated diarrheal form). And endopthalmitis

Front 93

This is found nearly ubiquitously everywhere and if frequently carried by animals, and is often present in manure and fertilizer.

A. Bascillus anthracis
B. Bascillus cereus
C. Listeria monocytogenes
D. Corynebacterium diptheriae

Back 93

C. Listeria monocytogenes

Contamination usually arises from raw foods or at point of food processing. It is commonly associated with dairy or meat products and is effectively controlled with pasteurization and sanitary measures.

Front 94

What are the three types of antthrax presentation?

Back 94

Cutaneous anthrax (most common. Papule with black necrotic center. Treated with antibiotics and most people recover.
Pulmonary anthrax: v deadly. 1-60 day incubation. Hemorrhagic necrosis of lymph nodes occur --> severe systemic infection. Many also develop meningitis.Characteristic diagnosis is chest radiogrpah showing widened mediastinum and gram positive bacilli on smear.
GI anthrax: dramatic intestinal inflammation, vomiting blood, diarrhea and severe pain. Very rare, but fatal.
CIPROFLAXIN is the treatment!

Front 95

What is characteristically diagnosed by chest radiograph showing widened mediastinum, and gram positive bacilli on blood smear or culture?

Back 95

Bascillus antrhacis.

Front 96

What is the treatment for anthrax?

Back 96

Ciproflaxin is the preferred antibiotic for treatment of B. anthracis, although doxycycline and others may also be effective.

Front 97

Bascillus anthracis produces two AB toxins. What are they and what is their mechanism and what do they cause? What is the B subunit?

Back 97

PA = protective antigen, the B subunit (basis of vaccine cuz this subunit binds em)
EF = edema factor. causes increase in cAMP and thus edema.
LF= lethal factor. causes decrease in MAPKKs, leading to necrosis and hypoxia.

Front 98

What conditions does B.cereus account for?

Back 98

Food poisoning (short term emetic, long term diahrreal) and endopthalmos.

Front 99

What is characterized by aerobic gram positive bacilli exhibiting tumbling motility?

A. Bascillus anthracis
B. Bascillus cereus
C. Listeria monocytogenes
D. Corynebacterium diptheriae

Back 99

C. Listeria monocytogenes

Front 100

How is Listeria effectively prevented/controlled for?

Back 100

Infections usually arise from food contamination, either of raw foods, or at the point of food processing. Listeria is commonly associated with dairy or meat products. So, it is effectively controlled by pasteurization and sanitary measures.

Front 101

True or False:
L.monocytogenes has special risks during pregnancy, as it can induce spontaneous abortion, stillbirth, or neonatal infection.

Back 101

True

Antiobiotic treatment is recommended for pregnant women and infants. Ampicillin or penicillin are the DOC.

Front 102

Which organism's virulence factors include: PrfA, internalins, listeriolysin, ActA, PI-PLC and PC-PLC? What does each do?

Back 102

The organism is L.monocytogenes. PrfA is transcription factor aka "mastor regulator". Internalins promote uptake by non-phagocytic cells. LLO allows escape from the phagocytic vacuole. ActA allows hijacking of host cytoskeleton to make actin comets. PI-PLC destabilizes phagosomes. PC-PLC promotes escape from secondary vacuole.

Front 103

Which organism is characterized by non-spore forming, gram-positive rods and are said to be like "Chinese letters".

Back 103

Corynebacterium

Front 104

How is diptheria spread?

Back 104

Very readily spread from person-to-person by either aerosols or direct contact with an infected individual. Presents as low-grade fever with localized inflammation of the throat/nasopharynx and perhaps an adherent membrane over the throat and tonsils. Systemic absorption of toxin secreted by bacterium leads progressively to labored breathing, pallor, sweating rapid heartbeat and possibly coma and death in 6-10 days. Treatment is antibiotic therapy combined with diptheria antitoxin therapy.

Front 105

True or False:
C. diptheriae only causes diptheria when it is lysogenized by a phage which carries the tox gene encoding a toxin.

Back 105

True

Front 106

Diptheria toxin words by causing ADP ribosylation of EF-2, causing an inhibition of....

Back 106

translation, thus leading to cell death.