Bacterial Pathogens - Zahrt Flashcards Preview

M2 Renal/Respiratory > Bacterial Pathogens - Zahrt > Flashcards

Flashcards in Bacterial Pathogens - Zahrt Deck (37):
1

How is respiratory divided?

Upper airway and Lower airway

2

Where can bacteria be found in the respiratory system?

In the upper airway. The lower airway is sterile

3

What defenses does the body have to prevent lower respiratory infection?

Size selection
Mucus secretions
Mucociliary elevator
Immune cells and response

4

How do pathogens spread into the lower airway?

Direct inhalation (>10um)
Aspiration from upper airway
Spread along mucus membrane
Direct implantation
Hematogenous spread

5

From a throat culture, you find a gram negative coccobasillus. What bacteria is this?

Bordetella Pertussis

6

Describe the pathogenesis of bordetella pertussis.

Binds to cilia using pertactin, filamentous hemaglutinin and pili. Pertussis toxin alters adenylate cyclase (G-i alpha) and produces massive amounts of mucus and damages the cilia.

7

What are the three stages of infection for bordetella pertussis?

catarrhal- runny nose, mild coughing, flu-like symptoms

paroxysmal- "barking" coughing fits, vomitting

convalescence- decrease in coughing, no vomitting

8

From a throat culture, you find a gram negative basillus arranged in pallisades. What bacteria is this?

Corynebacterium diptheriae

9

Describe the pathogenesis of corynebacterium diptheriae

Uses pili to attach to upper respiratory tract cells; produces diptheria toxin which modifies EL-2 and prevents protein synthesis.

Forms a pseudo membrane.

10

From a throat culture, you find a gram negative diplococci. What bacteria is this?

Neisseria meningitidis

11

How is neisseria classified by oxidase and catalase tests?

Oxidase +
catalase +

12

What diseases can neisseria meningitidis cause?

Pharyngitis
Pneumonia
Meningitis

13

Describe the pathogenesis of neisseria meningitidis

type IV pili allow it to bind to the cells of nasopharynx. It's polysaccharide capsule prevents it from being destroyed by either lysosomes or PMNs. It releases endotoxins and lipooligosaccharides as toxins.

14

Which four serotypes are included in the neisseria meningitidis vaccine?

A, C, Y, W135

15

From a throat culture, you find a gram positive cocci. It is catalase negative and beta-hemolytic. What bacteria is this?

streptococcus pyogenes

16

What diseases can streptococcus pyogenes cause?

scarlet fever
pharyngitis

17

Describe the pathogenesis of streptococcus pyogenes.

Capsule protects it from phagocytosis and complement.

Lipotechoic acid and T proteins mediate adhesion to the respiratory cells.

M proteins binds complement and immunoglobulins

Various DNAse, streptolysins, and peptidases chew up complement, blood cells, and pepetides.

pyogenic endotoxins produce sickness.

18

How is streptococcus pyogenes usually diagnosed?

Rapid antigen detection test; it is not usually cultured and tested.

19

From a throat culture, you find a gram positive cocci. It is catalase positive. What bacteria is this?

staphylococcus aureus

20

Describe the pathogenesis of staphylococcus aureus

Capsule protects it from phagocytosis

Expresses lipase, nuclease and hyaluronidase to chew up cells.

Lipotechoic acids and protein A promote cell binding

Coagulase activates fibrinogen into fibrin

various cytotoxins are released

21

From a throat culture, you find a gram positive cocci. It is catalase negative and alpha-hemolytic. What bacteria is this?

streptococcus pneumoniae

22

What diseases can streptococcus pneumoniae cause?

lobar pneumonia
sinusitis
otitis media

23

Describe the pathogenesis of streptococcus pneumoniae

pneumolysin
capsule
adehsion proteins

24

From a throat culture, you find a gram negative rod. It grows on chocolate agar. What bacteria is this?

Haemophilus influenzae

25

What special nutrient requirements does haemophilus influenzae have?

requires heme and NAD

26

What diseases can haemophilus influenzae cause?

pneumonia
sinusitis
epiglotitis
otitis

27

Describe the pathogenesis of haemophilus influenzae

capsule protects from phagocytosis

Outer Membrane Proteins and Pili help bind to epithelial cells

LOS causes inflammation

28

From a throat culture, you find a non-staining pleiomorphic cocci. It looks like a fried egg. What bacteria is this?

Mycoplasma pneumoniae

29

What diseases are associated with mycoplasma pneumoniae?

tracheobronchitis
atypical pneumonia

30

Describe the pathogenesis of mycoplasma pneumonia

Bacteria uses the P1 to attach next to the cilia, release toxins and destroy the cilia.

31

From a throat culture, you find a gram negative rod. It is oxidase positive. What bacteria is this?

Pseudomonas aeruginosa

32

What disease is pseudomonas aeruginosa infection associated with?

Cystic fibrosis, but could be any immunocompromised individual.

33

Describe the pathogenesis of pseudomonas aeruginosa

Opportunistic infection
Forms a biofilm
Attaches to endothelial cells via adhesins and pilins
Releases various enzymes and endotoxins

34

From a throat culture, you find a gram negative rod. It only grows on charcoal yeast extract. What bacteria is this?

Legionella pneumophilia

35

What diseases can legionella pneumophilia cause?

Pontiac fever
Legionnaire's Disease

36

Describe the pathogenesis of pseudomonas aeruginosa

survives inside alveolar macrophages
produces endotoxins

37

Describe the pathogenesis of mycobacterium tuberculosis

bacteria produce mycolic acids and liparabinomannan
PMNs over react causing necrosis

Decks in M2 Renal/Respiratory Class (50):