bacteria : part 3 Flashcards Preview

B2: microbiology > bacteria : part 3 > Flashcards

Flashcards in bacteria : part 3 Deck (20)
Loading 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

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



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