majury - normal flora Flashcards
what is the biggest vector of disease?
water
what is normal flora?
The bacteria that are consistently associated with a host. some theories say that we are a side effect of a microbial world and there there are more microbes in us than human cells.
t or f, having a C-section can effect your babies micro biome?
true, vaginal birth babies will have a larger microbiome
what is the primary defender against inhaled pathogens? what does it include?
the nose: cilia and mucus
Explain Staph Aureus located in the nose
this is a normal flora that s kept in “check” by other bacteria (staph epidermis). If it is not kept under control it can become pathogenic
explain the mouth and oral cavity microbiota
- 10^10 microbes here.
- saliva and pH prevent many species from living here
- thrush is an example of a oral cavity bacterial infection
what bacteria is the most common cause of UTI’s and neonatal meningitis?
urinary tract infections –> E. Coli
what is symbiosis?
nature of a relationship between two living things
what is mutualism
a relationship in which both parties receive benefit from living in close association (usually intimate)
What is commensalism?
one symbiont benefits (this is the commensal organism) and the other is unaffected.
what is parasitism?
one symbiont is benefited and the other is harmed
true or false, parasitic relationships can become mutualistic over time?
true, symbiosis changes with time
What are the three main benefits of normal flora to the host?
- synthesize vitamins
- prevent pathogen colonization
- produce substances that inhibit non-indigenous bacterial species
What are another 3 functions of the normal flora?
- stimulate development of certain tissues
- produce anti-bodies
- affect mental and physical health
t or f, your normal flora can cause infection / disease
true, if your normal flora is disrupted one may grow out of control and affect you.
what is opportunistic infection? what is pathogenicity? What are obligate pathogens? What is life?
- opportunistic infection is when your normal flora become pathogenic
- pathogenicity is the ability of a microbe to cause disease
- obligate pathogens do NOT associate with their host except in the case of disease.
- life’s good
what is the difference between a bacteria invading a host and infecting a host?
invade –> spread to adjacent tissues (initial entrance of bacterium)
Infect –> focal point of infection.
what are the 7 steps to an infectious disease?
- infectious agent
- reservoir (chills) in area
- transport to host (vector/fomites)
- attachment/colonization
- invasion
- infection (now growth and dissemination occurs)
- departure from host which spreads disease
what is constitutive defence?
natural / innate defence. general protection common to all animals
what is inducible defence
immune system that must be turned on upon pathogenic exposure.
what is toxigenesis?
ability to produce toxins
what are bacterial toxins?
soluble substances that alter the normal metabolism of host cells with deleterious effects on the host.
what is an endotoxin?
LPS is a example. These are associated with the cell wall of gram negative bacteria . These are only released if the cell lyses)
what is an exotoxin?
these are proteins. these are released from bacterial cells and may act at tissue sites removed from the site of bacteria.
explain exotoxin characteristics
- soluble proteins secreted by bacteria during exponential growth
- specific with bacterial strains
- virulent strains are toxin producers
Exotoxin effects: Damage to cell membranes
causes integrity of cell membrane to weaken allowing for cell lysis and infection spread to occur
Exotoxin effects: inhibit protein synthesis
self-explan
Exotoxin effects: activate 2nd messengers
these toxins can target cells and alter their functionality of proteins without directly killing the target cell.
Exotoxin effects: effects on Nt’s
endotoxins can inhibit the release of nt’s such ach innervating muscle. can alos promote the continued release of nt’s. `
Exotoxin effects: activate the host immune response..
- super-antigens (immunopathology)
- e.g. massive amount of cytokines being released
TSST = toxic shock syndrome toxin
