bacteria : part 3

Question 1

Outline the location of DNA in bacteria

Answer 1

hey just have their genetic material and ribosomes floating in the cytoplasm, as well as a cell wall

Question 2

How does capsule contribute to virulence Example

Answer 2

Capsule (protect against phagocytosis) i.e. Streptococcus pneumoniae

Question 3

How does endospores contribute to virulence Examle

Answer 3

Endospores (metabolically dormant forms of bacteria) heat, cold, desiccation and chemical resistant i.e. Bacillus sp. and Clostridium sp.

Question 4

3 types of exotoxin

Answer 4

Neurotoxin Enterotoxin Tissue invasive exotoxin Miscellaneous exotoxin Pyrogenic exotoxin

Question 5

Outline 2 types of enterotoxin withexamples

Answer 5

1. Infectious diarrhea Vibrio cholera, Escherichia coli, Shigella dysenteriae and Campylobacter jejuni 2. Food poisoning Bacillus cereus or Staphylcoccus aureus

THEY ACT ON THE GI TRACT

Question 6

Define outbreak

Answer 6

An outbreak is a greater-than-normal or greater-than-expected number of individuals infected or diagnosed with a particular infection in a given period of time, or a particular place, or both.

Question 7

Who does HUS affect more

Answer 7

usually the hemolytic-uremic syndrome is very rare in adults

Question 8

What can be done with genetics in an outbreak

Answer 8

You can sequence the gene in the bacteria to find the virulent genes You can then do PCR on people to confirm this e.g on stool samples

Question 9

What is the function of subunit A and the B subunits in shiga toxin

Answer 9

StxA is enzymatically active domain. StxB pentamer is responsible for binding to host cell receptors.

Question 10

Where is aggregative adherence fimbriae (AAF) located

Answer 10

genes encoding for AAF are on a plasmid mobilized between strains

Question 11

Outline the replication of Chlamydia trachomatis

Answer 11

Obligate intracellular pathogen Cannot culture outside of cell

Question 12

What is the structure of Neisseria gonorrhoeae

Answer 12

Diplococcus (pairs of cocci, can remember as looks like two balls and gonorhea is an STI……)

Question 13

What is the important virulence of N gonorrhoeae

Answer 13

pili and antigenic variation escape detection and clearance by the immune system

Question 14

T/f shigella releases shiga toxin

Answer 14

Can do! Shigella dysenteriae

Question 15

What disease does vibrio cholera cause

Answer 15

Cholera is an acute, severe diarrheal disease Without prompt rehydration, death can occur within hours of the onset of symptoms

Question 16

How did cholera acquire cholera toxin

Answer 16

It was infected with a first bacteriophage which gave it a gene to code for a receptor (type IV fimbria) The type IV fibria then allowed binding of a second bacteriophage The second bacteriopage gave the gene for the cholera toxin

Question 17

How can cholera toxin be treated

Answer 17

Enkephalins bind to the opioid receptors on enterocytes, which act through G proteins to inhibit the stimulation of cAMP synthesis induced by cholera toxin, thereby directly controlling ion transport

Question 18

Risk group for listeria monocytogenes

Answer 18

Risk group immuno-compromised, elderly, pregnant and their fetus

Question 19

Define Antimicrobial Antibacterial Antibiotic

Answer 19

Antimicrobial interferes with growth & reproduction of a ‘microbe’ Antibacterial commonly used to describe agents to reduce or eliminate harmful bacteria Antibiotic is a type of antimicrobial used as medicine for humans, animals originally referred to naturally occurring compounds

Question 20

Outline concentation for Hospitals as a source of infection

Answer 20

there are more people with infection in the environment, increasing risk