Micro

Question 1

If asplenic/sickle cell disease, what immunizations are needed against encapsulated m/o?

Answer 1

N. meningitidis, S. pneumonia, H. influenzae

Question 2

What vaccines are consisted of against encapsulated m/o?

Answer 2

Capsular polysaccharide + protein conjugate –> serves as antigen in vaccine

Question 3

What are encapsulated m/o?

Answer 3

S. pneumonia, B streptococcus (s. agalactie), n.meningitidis, h. influenza b, pseudomonas aeruginosa, Salmonela typhi, klebsiela pneumonia, E.coli

Question 4

Why carrier protein is needed in encapsulated m/o vaccines?

Answer 4

To increase immunogenicity. A polysaccharide antigen cannot be presented to T cells. But protein promotes T cell activation and subsequent class switching ( thus incr. immunogenicity).

Question 5

What are pneumococcal vaccines?

Answer 5

PCV13 (conjugated); PPSV23 (not conjugated)

Question 6

What catalase does?

Answer 6

It converts H2O2 into H2O and O2, before it can be converted to microbicidal products by the enzyme myeloperoxidase.

Question 7

What m/o (oxygen dependence) are susceptible to oxidative damage?

Answer 7

Anaerobes: clostridium; bacteroides; fusobacterium; actinomyces israelli. THEY LACK CATALASE and/or SUPEROXIDE DISMUTASE.

Question 8

3 features of anaerobes?

Answer 8

Foul smelling (short chain fatty acids)
Difficult to culture
Produce gas in tissue (CO2 and H2)

Question 9

What are facultative anaerobes?

Answer 9

Streptococci, staphylococci, enteric gram negative bacteria

Question 10

how facultative anaerobes produce energy?

Answer 10

They use O2 as a terminal electron acceptor to generate ATP
OR
can use fermentation or other O2-independent pathways.

Question 11

What antibiotic is used as a test to define staphylococci?

Answer 11

Novobiocin

Question 12

What antibiotic is used as a test to define alpha hemolysis causing streptococci?

Answer 12

Optochin

Question 13

What antibiotic is used as a test to define beta hemolysis causing streptococci?

Answer 13

Bacitracin

Question 14

Alpha hemolysis m/o? Hemolysis mechanism

Answer 14

Strp. pneumoniae; Strp. viridans

Partial reduction of Hb –> greenish or brownish color WITHOUT CLEARING AROUND GROWTH

Question 15

Beta hemolysis m/o? Hemolysis mechanism

Answer 15

Strp. A (pyogenes); Strp. B (agalactiae); Staph. aureus

Complete lysis of RBCs –> CLEAR AREA AROUND GROWTH

Question 16

6 m/o that form spores.

Answer 16

Bacillus anthracis and cereus;

Clostridium tetani, botulinum, difficile, perfringens

Question 17

Rusty sputum caused by …………………..

Answer 17

s. pneumoniae

Question 18

What m/o cause subacute endocarditis?

Answer 18

S. sanguinis (viridans group) –> makes dextrants, that bind fibrin-platelet aggregates on damaged valves
S. bovis
Enterococci (faecalis and faecium) –> following GI/GU procedures, because it is normal colonic flora

Question 19

What does pertussis toxin?

Answer 19

disables Gi –> impaired phagocytosis
disabled chemokine receptors for lymphocytes –> lymphocytosis –> impaired phagocytosis because lymphocytes cannot move to tissue.

Question 20

What does cyclase toxin by bordetella pertussis?

Answer 20

increases cAMP

Question 21

What does tracheal cytotoxin by bordetella pertussis?

Answer 21

damage cilliated epithelial tissue

Question 22

Legionnaire’s disease symptoms?

Answer 22

severe pneumonia + GI + fever +CNS symptoms

Question 23

Population of Legionnaires disease?

Answer 23

Smokers and chronic lung disease

Question 24

What causes pontiac fever?

Answer 24

Legionella pneumophila. Its mild flu-like symptoms. self limiting

Question 25

How to assess Legionella? (3)

Answer 25

1. Silver stain
2. Charcoal yeast extract medium with cysteine and iron
3. Urine test –> antigen