Cardiovascular Infections 2 MICRO

Question 1

Staph aureus is coagulase ______

Answer 1

Positive

Question 2

Optotchin test is useful to differentiate between ________

Answer 2

Streptococcus

Question 3

Patient with prosthetic valve endocarditis and the bacteria is coagulates negative. What is the most likely microorganism ?

Answer 3

Staph epidermidis

Question 4

How to differentiate between staph epidermidis and staph aureus:

Answer 4

• coagulase test

- MSA (mannitol salt agar)

Question 5

What does coagulase do? (Seen in staph ______ )

Answer 5

Clots plasma by intiating fibrin polymerization;

Staph aureus = coagulase positive

Question 6

How does being catalase positive add to a microorganism’s pathogenicity?

Answer 6

Catalase breaks down hydrogen peroxide to water and oxygen so it helps them survive the respiratory burst

Question 7

If the color of the mannitol salt agar changes from red to yellow, what organism could it be and why?

Answer 7

Staph aureus because it ferments mannitol and thus ↓ pH by producing acid

Question 8

What pathogen causes rheumatic fever/ heart disease

Answer 8

Step pyogenes

Question 9

What is an example of group A strep?

Answer 9

Strep pyogenes;

Question 10

What which group strep is responsible for impetigo, strep through or skin infections?

Answer 10

Group A (strep pyogenes)

Question 11

What is grouping criteria of the viridans streptococci

Answer 11

• whatever remains after the β hemolytic streptococci, enterococci and pneumococci are excluded from the streptococci
• have a green color; α hemolysis

Question 12

what are some organisms in the viridans streptococci group?

Answer 12

S. Mutans (dental carries)
S. Sanguinis (most common cause of infective endocarditis due to strep)
S. Mitis

Question 13

What specific organism is the most common streptococcus cause of IE?

Answer 13

Strep sanguinis

Question 14

__________ is how you differentiate between staph and strep.
Staph:
Strep:

Answer 14

Catalase test

Staph: catalase positive
Strep: catalase negative

Question 15

If you have a gram postive cocci that are catalase negative and alpha hemolytic, how do you differentiation between the two potential ones: ___________ and _________

Answer 15

Options would be: strep pneumonia and most viridans strep

Do a optochin test to differentiate between these two.

Strep pneumonia is optochin SENSITIVE while viridans strep group is optochin RESISTANT

Question 16

How do you differentiate between catalase negative and β hemolytic organisms: ________ and _______

Answer 16

Use a bacitracin test to differentiate between: strep pyogenes and strep agalactiae

Pyogenes: bacitracin sensitive
Agalactiae: bacitracin resistant

Question 17

Catalase negative and gamma hemolytic (no hemolysis) is most likely ________

Answer 17

Enterococcus

Question 18

_______ hemolysis will have green color around colonies due to ________

Answer 18

Alpha; incomplete lysis of RBC

Question 19

Methicillin resistance is seen mostly in __________ and ________ staph organisms and the genes for resistance is carried on _________

Answer 19

Staph aureus and staph epidermidis;

SCCmec (staphylococcal cassette chromosome) which condo does for mecA

Question 20

What doe mecA encode for in methicillin resistant bacteria?

Answer 20

Produces an altered PBP2a → ↓ affinity for methicillin which is a β lactate antibiotic that interferes with bacterial transpeptidation

Question 21

Methicillin blocks __________

Answer 21

Cross linking of peptidoglycan cell wall

Question 22

Methicillin resistance is an example of _______________ form of resistance

Answer 22

Altered target form of resistance

Question 23

Rheumatic heart disease/rheumatic fever is caused by ___________ (pathogen)

Answer 23

Strep pyogenes

Question 24

__________ → type _____ HS. → rheumatic fever → rheumatic heart disease

Answer 24

Step throat/pharyngitis → type II HS (M protein)

Question 25

If strep throat is not treated with antibiotics, it can lead to __________

Answer 25

Rheumatic fever/heart disease which can lead to pancarditis: myocarditis, pericarditis and endocarditis

Question 26

Enterococcus is a gram ________ cocci

Answer 26

Positive

Question 27

Infection by __________ originates from the genitourinary or GI tract

Answer 27

Enterococcus

Question 28

HACK organisms are gram _______ and they are:

Answer 28

NEGATIVE;

Haemophilus 
Aggregatibacter (Actinbacillus) actinomycetemomitans 
Cardiobacterium hominis 
Eikenella corrodens 
Kingella kingae

Question 29

HÁČEK organism often colonize the ___________ and causes 5% of the cases of ________

Answer 29

Oropharynx; endocarditis

Question 30

What’s the difference in the endocarditis caused by HÁČEK vs the non HÁČEK group

Answer 30

HÁČEK group caused endocarditis occurs in younger people (47 vs 60), oslers node’s and vascular immunological phenomena occur more common than in non HÁČEK caused endocarditis

Question 31

What organisms can cause culture negative endocarditis? (Intracellular)

Answer 31

• bartonella henselae and bartonella Quintana

Question 32

Body lice is associated with which microorganism

Answer 32

Bartonella Quintana (trench fever)

Bartonella is gram negative and facultatively intracellular

Question 33

What is important to look for in the patients history in diagnosing myocarditis

Answer 33

-history within the last 1-2 weeks of flu like symptoms (fever, joint pain, malaise), pharyngitis, tonsillitis or upper RTI

Question 34

The most common cause of myocarditis is _______

Answer 34

EnteroVIRUSES (coxsackie)

Question 35

__________ species of fungi can cause myocarditis in immunocompromised patients

Answer 35

Candida

Question 36

A complication of pneumonia is what type of inflammation in the heart?

Answer 36

Pericarditis

Question 37

Which viruses are associated with pericarditis?

Answer 37

Coxsackievirus A and B, HIV, hepatitis, measles, mumps, varicella zoster virus

Question 38

Risk factors for pericarditis

Answer 38

• pneumonia
• infection in other parts of the heart
• surgery
• catheter to drain pericardial fluid
• trauma