Disease causing microorganisms new Flashcards
Are microbes the enemy?
Microbes are not the enemy – less than 1% of them can directly make us ill.
What microbes are healthy?
Human microbiota
Gut microbiota
Probiotics
Prebiotics
What is the human microbiota?
Collective microorganisms that live
on/in the human body
What is the Gut Microbiota?
The collection of microorganisms (bacteria, archaea) which live and thrive in the digestive systems of humans.
think back to ‘gut flora’ – Fecal
transplant (most common phyla in healthy stools –
Bacteroidetes and Firmicutes)
What are Probiotics ?
live bacteria and yeasts promoted as having
various health benefits. They’re usually added to yoghurts or taken as food supplements
What are prebiotics?
The collective name for food components
that can promote the growth of beneficial bacteria.
How can someone be infected without disease?
Cytomegolovirus (CMV) seroprevalence in the adult population of Germany.
People will catch this in early life and will have it for their entire life.
Define pathogen.
A pathogen is an organism that causes a disease to develop in a host. There are many different kinds of pathogens in all shapes and sizes. They include viruses and bacteria as well as many eukaryotes.
Every living organism is affected by pathogens. Bacteria can be targeted by viruses called phages, which some scientists believe may have led to the development of complex life.
When is something an infection?
When pathogenic microbes enter the body and reproduce this is an infection
When is something considered to be a disease?
When the infection causes damage to an organisms function or systems then
this is referred to as disease
What can primary infection lead to?
Primary infection can predispose and lead to chronic or secondary disease.
What has been found to link with EBV?
Risk of multiple sclerosis
What does the Germ theory of disease state?
This theory states that microorganisms can cause disease (pathogens or germs)
what is a microorganism according to the germ theory?
a tiny unseen organism, not visible without magnification,which invade humans and animals which become hosts. They grow and reproduce and cause disease
What is a germ according to the germ theory?
Germ referring to any type of mircroorganism.
What are diseases caused by germs termed as according to the germ theory?
Diseases caused by germs are termed an infectious disease
What were Koch’s experiments?
Kochs Experiments:
Method:
1. Isolate germ
2. Grow it in culture
3. Inject it (into animal for instance)
4. Look for the disease
Types of
Microorganisms?
- Viruses
- Bacteria
- Fungi
- Protozoa
- Algae (blue/green)
- Worms
- Insects (ticks, lice, etc.)
- Prions (a specific type of misfolded
protein)
In what environment are TB symptoms more likely to show?
Lots of vitamin d is associated with suppressing TB infection. TB symptoms are more likely to show in less sunny environments.
What are some symptoms of salmonella?
- Diarrhoea, fever, vomiting, abdominal cramps 12 to 72 hours after infection, dehydration, self limiting gastrointestinal disease.
- In severe cases, Salmonella can move from intestines to bloodstream (aka typhoid fever)
structure of salmonella?
rod-shaped and have flagella so can move
Is salmonella gram positive or gram negative?
gram negative
What type of microbe is salmonella?
bacteria
What were Koch’s Postulates - Identification
of Pathogen causing disease [FULL]
Four generalized principles demonstrating microorganisms cause disease
1. The microorganism must be found in abundance in all organisms
suffering from the disease but should not be found in healthy organisms.
2. The microorganism must be isolated from a diseased organism and
grown in pure culture.
3. The cultured microorganism should cause disease when introduced into
a healthy organism.
4. The microorganism must be re-isolated from the inoculated, diseased
experimental host and identified as being identical to the original specific
causative agent.
Define Kochs postulates in identifying disease causing pathogens?
They were Four generalized principles demonstrating microorganisms cause disease
What is Kochs first principle/postulate?
- The microorganism must be found in abundance in all organisms suffering from the disease but should not be found in healthy organisms.
What is Kochs second principle/postulate?
- The microorganism must be isolated from a diseased organism and
grown in pure culture.
What is Kochs third principle/postulate?
- The cultured microorganism should cause disease when introduced into
a healthy organism.
What is Kochs fourth principle/postulate?
- The microorganism must be re-isolated from the inoculated, diseased
experimental host and identified as being identical to the original specific
causative agent.
WHat has Kochs experimental methods help discover?
Identified specific causative agents of
tuberculosis, cholera, anthrax
What is the threat/danger level of e.coli?
Most E. coli strains are harmless, and some are naturally found in the intestines and microbiome of humans, playing an important role in keeping the intestines healthy.
Structure of e.coli?
rod shaped.
Is e.coli gram positive or gram negative?
Gram negative
Where is e.coli commonly found?
Intestine
Define serotype
A group of microorganisms which have a particular variation which makes them distinguishable from other groups of the same species.
Symptoms of e.coli?
Some serotypes can cause food poisoning
When can e.coli mutliply rapidly and then become dangerous?
In people who are Immunocompromised, malnourished, secondary infections, opportunistic growth.
Define immunocompromised.
weak/underperforming immune system
Define opportunistic growth/opportunistic infections.
Infections that arise due to an abnormally weak immune system because the immune system cannot kill the bacteria quick enough.
Define secondary infection.
An infection which occurs during or following a first infection
What can cause a weak immune system?
Immunocompromised, malnourished, secondary infections, opportunistic growth
What type of microbe is e.coli?
bacteria
How does e.coli help the health of the gut?
- protects us from other harmful microbes.
- forms a biofilm
define self limiting disease.
A disease which runs its course and resolves on its own with or without specific medical intervention.
eg: common cold
What is a disease caused by staphylococci?
Staphylococcal enteritis
Structure of staphylococci?
small, round cocci shape (cocci shape = spherical/roud shape).
What is staphylococci a major cause of?
food poisoning
Symptoms of staphylococci?
Rapid onset (1-8 h), nausea, explosive vomiting, abdominal cramps, headache, diarrhoea
What is the onset of symptoms of staphylococci?
Rapid onset (1-8 h), nausea, explosive vomiting, abdominal cramps, headache, diarrhoea
How long do symptoms of staphylococci last?
Symptoms last for approximately 1 day to 48 h
Describe Staphylococcal enterotoxin
heat stable toxin, resistant to digestive protease
WHat are some treatments of staphylococci?
management of symptoms (electrolyte replacement) avoid foods high in fibre / difficult to digest
What type of microbe is staphylococci?
bacteria
WHat disease is caused by Campylobacter?
Campylobacteriosis
How does Campylobacter enter the body?
faecal-oral route, ingestion of contaminated food / water, raw / undercooked meat
What are some symtptoms of campylobacter?
usually self-limiting, causes diarrhoea, fever, stomach cramps.
Is campylobacter self limiting?
Yes
Treatments for campylobacteriosis/campylobacter?
Its self limiting, so will resolve on its own, most will not need antibiotics.
Management
Drink lots of fluids
Antibiotics for children and for immunocompromised or at risk of systemic infection
What illness does clostridium botulinum cause?
botulism
structure of clostridium botulinum?
rod-shaped spore forming bacteria
How common clostridium botulinum?
rare but serious and potentially fatal
How does clostridium botulinum work?
Blocks neuromuscular junctions → causes paralysis
Where are Clostridium botulinum found?
bacterial spores found in contaminated soil and water and dust.
Can also contaminate dust.