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Flashcards in bacterial virulance factors Deck (43):
1

what is the major virulance factor of strep pneumo?

polysaccharide capsure that prevents phagocytosis

other virulance factors:
IgA protease (inactivates secretory IgA)
adhesins (necessary for adhesion to epithelial cells)
pneumolysin (cytotoxin that causes pores in cell membrane and cell lysis)

2

what is the major virulance factor for bacillus anthacis?

capsule formed from D-glutamic acid inhibits phagocytosis

3

what is the major virulance factor for group A strep?

M protein - present in cell wall, interferes with opsinization by the alternative pathway compliment (C....?), M-protein also binds to fibrinogen resulting in flammatory mediator release and vascular leakage

4

Does gonorhea have a capsule?

NO - N. meningiditis does not not N. gono

5

how does gonorrhea establish an infection

pili attach to host epithelial cells

gono is motile but has no flagella - movement from attachment and contraction of pili

6

what virulance factor is responsible for the pathogenicity of H. influenza?

type B capsule consisting of polyribitol phosphate

contains pentose monosaccarides rather than hexose sugards as carbohydrate component of capsule

can cause septic arthritis secondary to hematogenous dissemination from otitis media

growth requires X factor (hematin) and V factor (NAD+)

7

what is the virulance factor for mycoplasma pneumonea?

protein P1 - adheres to respiratory epithelial cells - no cell wall, only membrane packed with sterols (requies cholesterold for growth media).

8

1)Staph aureus -
2)SHiN organisms -
3)Gp A Strep -
4)N Meningitidis, E coli, V cholerae -
5)C diphtheriae -
6)spores -
7)Cl perfringes -
8)Bacillus anthracis -
9)Listeria -
10)Mycobac TB -
11)Meningococcus -
12)H influenzae - polyribitol phosphate capsule, satellite phenomenon
13)E coli - lipid A - for presentation with shock
K1 capsular Ag - virulence factor
fimbriae - adhesion factor
14)Yersinia pestis - envelope Ag

1- protein A - binds Fc of IgG
2-IgA protease
3-M protein
4-Fimbriae/pili
5-Transduction beta prophage
6-diplicolinic acid in core
7-lecithinase alpha toxin
8-D-glutamate in capsule
9-Actin rockets, listerolysin O
10-sulfatides,cord factor,tuberculin
11-capsule
12-polyribitol phosphate capsule, satellite phenomenon
13-lipid A - for presentation with shock, K1 capsular Ag (virulence factor),
fimbriae (adhesion factor)
14- envelope Ag

9


What are the virulance factors for Staphylococcus aureus

1) Protein A = binds to Fc of IgG; inhibits component fixation and phagocytosis
2) Toxic Shock Syndrome Toxin(TSST) = superantigen that binds MHC II and T-cell receptor and causes polyclonal T-cell activation

10


What are the virulance factors for Streptococcus pneumoniae



1) IgA protease
2) Capsule
3) Pneumolysin

11


What are the virulance factors for Streptococcus pyogenes(Group A)


1) M protein = inhibits complement fixation, resists phagocytosis
2) Streptolysin O, S = cytolytics
3) SpeA, Spec, etc = pyrogenic exotoxins

12


What are the virulance factors for Viridans group Streptococcus

1) Glycocalyx = aids in sticking to damaged valves

13

What are the virulance factors for Streptococcus agalactiae(Group B)



1) CAMP factor = enlarges area of hemolysis

14


what should you know about Enterococci(Group D)



1) Vancomycin resistance leads to VRE

15

What are the virulance factors for Corynebacterium diphtheria


1) Diphtheria toxin = exotoxin inhibits protein synthesis via ADP-ribosylation of EF-2

16

what are the encapulated bateria?

SHiNE SKiS
S. pneumo, Hib, N. meningitidis, E. Coli, Salmonella, Klebsiella, Group B Strep

17

what are the SHiN organismss? what is their common virulance factor?

Strep. pneumo
H. influenza
Niserria meningiditis

IgA protease

18

what is the virulance factor for Clostridium perfringens?

1) Alpha toxin("lecithinase," a phospholipase) = causes myonecrosis(gas gangrene) and hemolysis

19

what are the virulance factors for Bacillus anthracis?

1) Edema Factor(EF) = mimics adenylate cyclase(inc cAMP)
2) Lethal Factor(LF) = protease that cleaves MAP kinases
3) Protective Agent(PA) = binds to host cell and facilitates entry of EF, LF
3) Polypeptide capsule(uses D-glutamate)

20

Neisseria gonorrhoeae

1) Pili(fimbriae)
2) IgA proteases
***Note: NO CAPSULE, unlike N. meningitidis

21

Which Bacteria/toxins Inactivate EF-2

1) Corynebacterium diphtheria = diphtheria toxin = ADP ribosylation of EF-2
2) Pseudomonas aeruginosa = Exotoxin A = ADP ribosylation of EF-2

22

what is unique about Pneumocystis jirovecii?

1)fungus with No ergosterol in cell membrane

23

Bacillus cereus

1) Cereulide = cytotoxin that destroys mitochondria

B. cereus infection causes nausea and vomiting

24

what is the virulance factor for Dermatophytes?

1) Keratinase

25

association for Actinomyces

1) Sulfur granules(not a virulence factor,)

26

Mycobacterium tuberculosis

sulfatides (inhibit phagosome-lysosome fusion - allows it to survive and multiply IN MACROPHAGES),
cord factor (causes release of TNF-alpha),tuberculin
1) Mycolic acid in cell wall

catylase positive,
aerobic
LPS but NO LIPID A, so no exotoxin or endotoxin

can be grown with radioactive palmitate as carbon source allowing faster detection (still 1-2 weeks)

false negative PPD in AIDs or immunosuprerssed!

27

what is the virulance factor for Mycobacterium leprae

1) Mycolactone = cytotoxic and immunosuppressive

28

what are the virulance factors for Neisseria meningitidis

1) Lipooligosaccharide(LOS) = analogous to LPS in Gm- bacteria and acts as an endotoxin
2) Capsule
3) IgA Proteases

29

what is the virulance factor for Neisseria gonorrhoeae

1) Pili(fimbriae)
2) IgA proteases
***Note: NO CAPSULE, unlike N. meningitidis

30

what is the virulance factor for Haemophilus influenzae

1) Capsule = type B most virulent
2) IgA proteases

31

what are the virulance factors for Pseudomonas aeruginosa

1) Capsule = slime layer; CF strains are mucoid
2) Exotoxins = exotoxin A(inactivates EF-2), Exoenzyme B, cytotoxin(leukocidin), and phospholipase C are all anti-phagocytic; elastase destroys tissue
3) Pigments = pyocyanin is toxic for leukocytes; also a yellow one

32

what are the virulance factors for E. Coli(general)

1) Fimbriae = impt. for cystitis and pyelonephritis
2) K Capsule = impt. for pneumonia, neonatal meningitis
3) LPS = septic shock

33

what is the virulance factor for ETEC E. Coli

1) Heat-labile toxin(LT) = activates adenylate cyclase similar to cholera to stimulate Cl- and H2O efflux(diarrhea)
2) Heat-stable toxin(ST) = activates guanylate cyclase to dec absorption of NaCl, water in gut

34

what is the virulance factor for EHEC E. Coli

1) Shiga-like toxin = inactivates 60S ribosome by removing adenine from rRNA; seen in HUS

35

what is the virulance factor for Klebsiella

1) Capsule(mucoid; can be quite large)

36

what are the virulance factors for Salmonella Typhi

1) Flagella(distinguishes from Shigella)
2) Vi capsular antigen(not in other Salmonella species)
3) Adhesion/invasion antigens(similar to Shigella)

37

what are the virulance factors for Shigella dysenteriae

1) Adhesion/invasion antigens(similar to Salmonella)
2) Shiga Toxin = inactivates 60S ribosome by removing adenine from rRNA; the bacterium can still cause significant disease without this toxin, making mucosal invasion the true virulence determinant

38

what is the virulance factor for Campylobacter jejuni

1) Flagella(single, polar)

39

what is the virulance factor for Vibrio cholerae

1) Cholera toxin = activates Gs and inc. cAMP via adenylate cyclase; inc Cl- and H2O efflux in gut

40

what is the virulance factor for Yersinia enterocolitica

1) LcrV antigen = secretion system
2) Yops(Yersinia outer proteins) = secretion system

41

what are the virulance factors for Helicobacter pylori

1) Urease
2) Flagella
3) CagA protein = surface complex that injects proteins into cell; correlates with more virulent strains
4) Vacuolating cytotoxin

42

what are the methods for visualizing Spirochetes, what are the major virulance factors?

1) Borrelia(visualized with aniline dyes - Wright's and Giemsa - and light microscopy)
2) Leptospira(darkfield)
3) Treponema(darkfield microscopy)
4) All have periplasmic flagella that are highly active and necessary for virulence

43

what are some importnat features of Mycoplasma pneumoniae? what is mechanism for the virulance facfor responsible for the very severe form of disease?

1) Lacks cell wall
2) Cholesterol in cell membrane
3) Terminal organelle = cytoskeletal and adhesive components impt. for motility and attachment
4) Community Acquired Respiratory Distress Syndrome(CARDS) Toxin = binds to surfactant proteins and ribosylates several proteins; not present in all strains, but worse when it is

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