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1

List the common virulence features for bacteria

Diverse secretion systems, Flagella (movement, attachment), Pili (important adherence factors), Capsule (protect against phagocytosis) i.e. Streptococcus pneumoniae ,Endospores (metabolically dormant forms of bacteria) heat, cold, desiccation and chemical resistant i.e. Bacillus sp. and Clostridium sp. Biofilms Exotoxin Endotoxin

2

Outline pyrogenic exotoxins

Stimulate cytokine release Staphylcoccus aureus or Streptococcus pyogenes

3

What is seen on the lipid bilayer of

On the lipid bilayer of gram negative bacteria, we see LPS and sugars – these are endotoxins

4

What can happen if lots of the LPS is shed

Then it can cause endotoxic shock Normally shed in steady amounts

5

Composition of shiga toxin

have an AB5 subunit composition Subunit a (StxA) is non-covalently associated with a pentamer of protein B (StxB).

6

Why is shiga toxin a mobile genetic element

Shiga toxins are encoded on a bacteriophage highly mobile genetic elements and contributes to horizontal gene transfer Toxins are highly expressed when the lytic cycle of the phage is activated (so that the gene can be taken up by lots of E coli)

7

Funciton of AAF

Allows binding to enterocytes AND allows binding to eachother to make biofim

8

Give example of BACTERIAL resp tract infections

Legionnaires’ disease (legionellosis) Legionella pneumophila (Gram -) Tuberculosis Mycobacterium tuberculosis (Gram +)

9

Where is legionella pneumophilia commonly found and what is the route of infection

 Lives in amoeba in ponds, lakes, air conditioning units  Infection route: inhalation of contaminated aerosols

10

What cells are affected in humans by legionella pneumophilia

 In humans L. pneumophila will infect and grow in alveolar macrophages  Human infection is “dead end” for bacteria – the bacteria can’t survive here on

11

What virulence factor is involved in L pneumophilia

Type IV secretion system There is a large protein spanning the 2 cell membranes and cell wall allows the bacteria to secrete effector proteins inside to out They are able to survive and replicate in macrophage vacuoles, because it can release special virulence factors due to the type IV system, and

12

Why is TB difficult to treat

Because it is grouped with gram +ve bacteria, but it has a very different cell wall Lots of lipids attached to the cell wall

13

What bugs cause gonorrhoea and syphilis

(Neisseria gonorrhoeae) and (Treponema pallidum) for syph

14

How can you acquire a Campylobacter sp. mostly C. jejuni infectin

Infection most likely through undercooked poultry

15

What is the virulence associated with salmonella sp

Type III secretion systems encoded on pathogenicity islands (SPI)

16

Outline type III secretion system with the bug using it

Salmonella sp. uses it I think this is the injectisome, can inject proteins into the cell SPI1: is required for invasion SPI2: intracellular accumulation

17

What is special about listeria

Can infect cell to cell without exiting and then re-entering It polyermises actin using profilin *see tutorial* Important for immunology and for research

18

What are the most frequent types of HAI

surgical site infections, urinary tract infections, pneumonia, bloodstream infections and gastrointestinal infections.

19

Outline intervention as a hospital source of infection

LINES (iv, central, arterial, CVP) CHEMO CATHETERS INTUBATIN PROSTHETICS Prophylactic antibiotics Inappropriate prescribing

20

Give examples of Enterobacteriaceae

E.coli, Klebsiella pneumoniae, Enterobacter sp.