MICR_041813 haemo_bordetella

Question 1

What are some characteristics of haemophilus influenza (Hi)?

Answer 1

gram (-) bacillus or coccobacillus, non-motile, non-spore forming, can be either encapsulated (typeable) or unencapsulated (non-typeable)

Question 2

What does encapsulated (typeable) haemophilus influenza cause?

Answer 2

acute meningitis in young children

Question 3

What does UNencapsulated (non-typeable) haemophilus influenza cause?

Answer 3

ear aches + respiratory disease; predominant form in population

Question 4

What is the critical virulent component of encapsulated (typeable) haemophilus influenza?

Answer 4

capsule - required for virulence because it confers anti-phagocytic properties

Question 5

There are 6 serotypes of encapsulated (typeable) haemophilus influenza. What’s the difference between them? Which one is the most virulent?

Answer 5

Types a-f. Type B has a ribose, while the rest has hexose. Type B is the most virulent one.

Question 6

What is the most common cause of meningitis in children under 4 y.o. up until the 90s?

Answer 6

type B encapsulated haemophilus influenza; reduction due to antibiotics and vaccines

Question 7

What kinds of symptoms can encapsulated haemophilus influenza cause? (5)

Answer 7

1) nasopharyngitis w. otitis media or sinusitis, 2) epiglottis + obstructive laryngitis, 3) cellulitis (rash), 4) pyarthrosis (pus in joint), 5) pneumonia

Question 8

What is the mechanism of pathogenesis of encapsulated haemophilus influenza?

Answer 8

aerosol droplets are inhaled, leading to respiratory tract colonization

Question 9

What are 3 virulence factors that encapsulated haemophilus influenza produce?

Answer 9

1) IgA protease - aids in immune evasion. 2) LPS - induces ciliary stasis. 3) capsule - antiphagocytic properties

Question 10

What are the 3 types of immunity can be developed against encapsulated haemophilus influenza?

Answer 10

1) passive immunity (0-4mo.), 2) acquired immunity (3-4yo), 3) vaccine

Question 11

When is the most susceptible age to encapsulated haemophilus influenza?

Answer 11

6-12mo

Question 12

What is the vaccine against encapsulated haemophilus influenza?

Answer 12

conjugated capsular vaccine: capsule protein (PRP) linked to diphtheria toxoid to increase dependence of T cells/memory and to increase immunogenicity

Question 13

How would you treat encapsulated haemophilus influenza?

Answer 13

Ampicillin, 3rd generation cephalosporin (cefotaxime, ceftrixone), Augmentin (ampicillin + clavulanate)

Question 14

What are some complications of encapsulated haemophilus influenza?

Answer 14

residual neurological damage, which can be reduced by incorporating corticosteroid into the treatment regime to reduce inflammation

Question 15

Where does UNencapsulated (non-typeable) haemophilus influenza usually infect?

Answer 15

generally respiratory tract and ear, but can also cause conjunctivitis or meningitis (usually in patients with predisposing factors, such as trauma, sinusitis, CSF leak)

Question 16

What are the virulence factors that UNencapsulated haemophilus influenza produce? (2)

Answer 16

1) adhesion molecules (Hap, HMW1/2, Hia, Hsf), 2) biofilm, which confers antibiotic resistance

Question 17

T/F UNencapsulated haemophilus influenza is an intracellular pathogen.

Answer 17

False. It is an intracellular AND extracellular pathogen

Question 18

What are the 3 routes that UNencapsulated haemophilus influenza use to invade cells?

Answer 18

1) macropinocytosis, 2) paracytosis (between tight junctions), 3) LPS-platelet activating factor

Question 19

What are the 3 types of immunity can be developed against UNencapsulated haemophilus influenza?

Answer 19

1) passive immunity (0-4mo.), 2) adults are susceptible to infection; not sure if long-term immunity develops b.c. of strain variation, 3) NO vaccine

Question 20

How would you treat UNencapsulated haemophilus influenza? (3)

Answer 20

1) amoxicillin, 2) amoxicillin w. b-lactamase inhibitor (clavulanate), 3) ceftriaxone

Question 21

T/F UNencapsulated haemophilus influenza is an obligate anaerobe.

Answer 21

False. It’s a facultative anaerobe

Question 22

Why are UNencapsulated haemophilus influenza considered “fragile”?

Answer 22

it is susceptible to disinfectants and drying

Question 23

T/F encapsulated haemophilus influenza can spontaneously convert to UNencapsulated haemophilus influenza.

Answer 23

True.

Question 24

Why is UNencapsulated haemophilus influenza considered a fastidious pathogen?

Answer 24

it requires growth factors X (hemin) and V (NAD or NADP) to grow.

Question 25

What type of medium would be appropriate for UNencapsulated haemophilus influenza? Inappropriate?

Answer 25

appropriate: CHOCOLATE AGAR, because the heating causes RBCs to release X, V via actions of staphylococci and streptococci. Inappropriate: BLOOD AGAR because it lacks factors X, and V

Question 26

How would you diagnose UNencapsulated haemophilus influenza?

Answer 26

1) blood + CSF culture - gram stain followed by growth on chocolate agar. 2) immunofluorescence - detect type B capsular antigen in spinal fluid. 3) biochemical tests

Question 27

What vaccine is available for UNencapsulated haemophilus influenza?

Answer 27

conjugate vaccine of H1b polysaccharide and carrier protein

Question 28

What does bordetella pertussis cause?

Answer 28

whooping cough

Question 29

What are some characteristics of bordetella pertussis?

Answer 29

gram (-) coccobacillus, obligate aerobe

Question 30

What are the hosts of bordetella pertussis?

Answer 30

humans only

Question 31

What is the epidemiology of bordetella pertussis?

Answer 31

highest fatality in children; immunization caused a dramatic decline

Question 32

What are the clinical features of bordetella pertussis?

Answer 32

upper respiratory symptoms characterized by two stages: 1) catarrhal stage, 2) paroxysmal stage

Question 33

What is the catarrhal stage of a bordetella pertussis infection?

Answer 33

runny nose, sneezing, low grade fever w. a mild occasional cough

Question 34

What is the paroxysmal stage of a bordetella pertussis infection?

Answer 34

burst of coughing (to dislodge mucus) followed by a high pitch "whoop" and occasional vomiting. Pts can turn blue/cyanotic.

Question 35

What is the pathogenesis of bordetella pertussis?

Answer 35

1) inhaled respiratory droplets 2) adherence to ciliated epithelial cells 3) multiplication and production of toxins, 4) local inflammation + mucous production, 5) patchy ulceration of respiratory epithelium, 6) diminished O2 supply and pneumonia

Question 36

T/F bordetella pertussis has the potential to cause bacteremia

Answer 36

No. it does not invade the bloodstream, it remains in the respiratory tract.

Question 37

What are the virulence factors (toxins) that bordetella pertussis produce? (4)

Answer 37

1) Dermonecrotic Toxin, 2) Tracheal cytotoxin, 3) Adenylate cyclase toxin, 4) Pertussis toxin (THINK: DTaP - same as the vaccine that is available!!)

Question 38

How does the pertussis toxin aid in bordetella pertussis's virulence?

Answer 38

inhibits adenylate cyclase, leading to cAMP ACCUMULATION. Leads to lymphocytosis, histamine sensitization, and insulin production

Question 39

How does the adenylate cyclase toxin aid in bordetella pertussis's virulence?

Answer 39

it catalyzes cAMP PRODUCTIONdirectly from ATP; IMPAIRED MACROPHAGE FXN and can cause CELL LYSIS

Question 40

How does the demonecrotic toxin aid in bordetella pertussis's virulence?

Answer 40

aka "Heat-Labile Toxin", which causes smooth muscle contraction that result in ischemic NECROSIS and INFLAMMATION of lung tissue

Question 41

How does the trachael cytotoxin aid in bordetella pertussis's virulence?

Answer 41

causes CILIOSTASIS, KILLS trachael epithelial cells, promotes CYTOKINE RELEASE

Question 42

What does the bordetella pertussis use to attach to lung epithelium? (4)

Answer 42

1) pili, 2) filamentous hemagglutinin (FHa), 3) pertactin, 4) trachael colonization factor

Question 43

T/F immunization with DTaP provides lifelong immunity.

Answer 43

False. It does not confer life-long immunity

Question 44

What is the difference between DTP and DTaP?

Answer 44

both are trivalent vaccines, but DTP can cause encephalopathy and permanent neurological sequelae. DTaP contains acellular pertussis and avoids problems observed with DTP

Question 45

How would you diagnose bordetella pertussis?

Answer 45

Using nasopharyngeal swabs, use 1) PCR, 2) culture test, 3) antibody test

Question 46

How would you treat bordetella pertussis?

Answer 46

Erythromycin, Tetracycline, Chloramphenicol

Question 47

What are the virulence determinants of proteus vulgaris/proteus mirabilis? (2)

Answer 47

flagella ("swarming" motility) and urease

Question 48

Why is urease production importance in the pathogenicity of proteus vulgaris/proteus mirabilis?

Answer 48

it converts urea into ammonia, which increases the pH/alkalinity of the urine, leading to an increase in chronic UTI

Question 49

Where is acinetobacteria normally found?

Answer 49

opportunistic infection in hospitalized patients, often associated with use of indwelling medical devices (IVs, grafts)

Question 50

What are the virulence factors of acinetobacteria?

Answer 50

capsule, adhesins, proteolytic and lipolytic enzymes

Question 51

What is characteristic of acinetobacteria that cause opportunistic infections?

Answer 51

multi-drug resistant strains are increasing

Question 52

How can you diagnose gram (-) pathogens? (3)

Answer 52

colony morphology, selective medium, and biochemical tests.

Question 53

Which gram (-) pathogens are facultative anaerobes?

Answer 53

1) proteus mirabilis, 2) e. coli, 3) enterobacter cloacae, 4) klebsiella pneumonia, 3) serratia marcesens (THINK: facultative anaerobe PEEKS out every once in a while for air)

Question 54

Which two gram (-) pathogens are aerobes?

Answer 54

1) acinetobacteria, 2) pseudomonas aeruginosa (THINK: aerobes Prefer Air)

Question 55

Which 3 gram (-) pathogens are lactose fermenters?

Answer 55

1) e. coli, 2) klebsiella pneumonia, 3) enterobacter cloacae

Question 56

How can Shigella be prevented?

Answer 56

better sanitation

Question 57

What is the Kigler Iron Agar test?

Answer 57

biochemical test that detects sugar (glucose, lactose) fermentation and gas (H2S) production

Question 58

How do you intepret a Kigler Iron Agar test?

Answer 58

Yellow Slant = fermented lactose. Yellow BUTT = fermented glucose. BLACK PPT = H2S production.