MMI Topic 12 Flashcards
What is the microbiome
The community of microbes (their genetic materials, and their secreted metabolites) that colonize various anatomical sites of the body
What is the microflora/microbiota
terms used interchangeably with microbiome BUT they are more specifically referring to microorganisms only
What is microbial antagonism
it is the competition between microbes
What are bacteriocins
a protein produced by one bacteria to protect the host from other bacterias
What are probiotics
live microbes that are intentionally ingested to provide health benefits
What is a prebiotic
ingredients in food that induce the growth or activity of beneficial microbes
Describe fecal transplants
process in which fecal bacteria from a healthy person is introduced to a recipient in the hopes of restoring healthy colonic microflora
What is an opportunistic infection
infection caused by pathogens that take advantage of a an opportunity not normally available such as weakened immune system, altered microbiota, or breached integumentary barriers
What is pathogenicity
ability of a microbe to cause disease
What is virulence
how harmful a pathogen is to a host
Describe the parenteral route
pathogen is inserted directly into the blood or the tissue beneath the skin or mucous membranes.
ex. insect bite
What are invasins
a class of proteins associated with the penetration of pathogens into the host cells
Describe antigenic variation`
when pathogens change the structure on their surfaces so the immune system does not recognize them during re-infection
What are cytopathic effects
Damage or death to the host cell (usually due to virus replication
What is septic shock and how does sepsis develop
severe and potentially fatal condition that occurs when sepsis leads to extremely low BP. Sepsis develops when the body has an extreme reaction to infection
What is a superantigen
proteins (usually bacterial) that stimulate a massive immune response
Describe endotoxins
Lipopolysaccharides on the outside of gram-negative bacteria cells that is released when the cell dies causing an immune system reaction
Describe exotoxins and how they are classified
proteins secreted by pathogens (usually gram + ones) that may be waste products or designed to gain access to host nutrients. they are classified based on their function
Describe enterotoxins
exotoxin that affects the intestinal tract
Describe Tetanus toxin
it is a neurotoxin that inhibits neuron function
Describe botulism toxin
neurotoxin that causes paralysis
What is E. choli O157:H7
Enterohemorrhagic E. choli. Causes bloody diarrhea and no fever. can also cause hemolytic-uremic and kidney failure
Name 5 places microbes live in the human body
- Skin
- Conjuctiva (ex. surface of the eye)
- Upper respiratory tract (ex. mouth, nose/throat)
- Lower digestive system (intestines)
- Urinary & reproductive system (urethra & vagina)
A patient dies of an E. choli infection after an intestinal puncture. Why does this microbe, which normally lives in the colon and is not harmful, killed this patient
in this case, the E. choli was an opportunistic pathogen. Because there was a puncture in his intestine the E. choli took advantage of the opportunity to infect.
What are mechanisms of pathogenicity
Requirements for infection and disease
What are the 6 mechanisms of pathogenicity
- Gain access (portals of entry)
- Be present in sufficient numbers to cause infection
- Attach/adhere to host cells
- Penetrate host defences
- Have virulence (be able to damage host cells)
- Be transmissible to new hosts (exit one host and infect another)
What are the 5 stages of disease and a brief description
- Incubation period- no signs/symptoms
- Prodromal period- vague general symptoms
- Illness- most severe signs/symptoms (death can occur)
- Decline- Symptoms decline
- Convalescence- no symptoms
How do Botulism toxins work?
caused by ingesting food infected with the toxin. it prevents the release of an inducing neurotransmitter that contracts muscles causing paralysis
How to tetanus toxins work
it prevents the release of an inhibitory neurotransmitter that stops muscle contraction and causes muscle spasms and spastic paralysis
what is the difference between sign vs symptoms
sign- a characteristic measured by an observer
symptom- a change in body function that is described by the patient
Chronic vs acute disease
chronic- persistent or long lasting
acute- a rapid onset or short course of disease
Sub-clinical vs latent disease
sub-clinical- an asymptomatic infection
latent- where the pathogen lies dormant in the body for a period of time
