bacteria : part 3 Flashcards
Outline the location of DNA in bacteria
hey just have their genetic material and ribosomes floating in the cytoplasm, as well as a cell wall
How does capsule contribute to virulence Example
Capsule (protect against phagocytosis) i.e. Streptococcus pneumoniae
How does endospores contribute to virulence Examle
Endospores (metabolically dormant forms of bacteria) heat, cold, desiccation and chemical resistant i.e. Bacillus sp. and Clostridium sp.
3 types of exotoxin
Neurotoxin Enterotoxin Tissue invasive exotoxin Miscellaneous exotoxin Pyrogenic exotoxin
Outline 2 types of enterotoxin withexamples
- 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
Define outbreak
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.
Who does HUS affect more
usually the hemolytic-uremic syndrome is very rare in adults
What can be done with genetics in an outbreak
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
What is the function of subunit A and the B subunits in shiga toxin
StxA is enzymatically active domain. StxB pentamer is responsible for binding to host cell receptors.
Where is aggregative adherence fimbriae (AAF) located
genes encoding for AAF are on a plasmid mobilized between strains
Outline the replication of Chlamydia trachomatis
Obligate intracellular pathogen Cannot culture outside of cell
What is the structure of Neisseria gonorrhoeae
Diplococcus (pairs of cocci, can remember as looks like two balls and gonorhea is an STI……)
What is the important virulence of N gonorrhoeae
pili and antigenic variation escape detection and clearance by the immune system
T/f shigella releases shiga toxin
Can do! Shigella dysenteriae
What disease does vibrio cholera cause
Cholera is an acute, severe diarrheal disease Without prompt rehydration, death can occur within hours of the onset of symptoms
How did cholera acquire cholera toxin
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
How can cholera toxin be treated
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
Risk group for listeria monocytogenes
Risk group immuno-compromised, elderly, pregnant and their fetus
Define Antimicrobial Antibacterial Antibiotic
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
Outline concentation for Hospitals as a source of infection
there are more people with infection in the environment, increasing risk
