Pathogens flashies Flashcards
microbiota
normal florapart of the innate immunitydo not cause disease (do some good)
commensalists or mutualists
how much does normal flora weigh?
5-10 pounds1/3 in feces also lots on skin
commensalism
neither harm or benefit the carrying host
benefits of flora?
produce Vit K
absorb nutrients
secrete bacteriocins
mutualism
symbioitic relationship between two organisms where both benefit
bacteriocins
released by normal flora to kill other bacteria
penicillinase bacteria
can interfere with therapy
breaks down penicillin
harm of flora
can be come pathogenic outside of normal niche
streptococcus viridans
in mouth
can get to heart during dental procedures and results in infections endocarditis
opportunistic pathogens?
normal flora outside of normal location can cause problems
resident normal flora?
costant and well defined
role in interference-compete for binding site, nutrients, and create metabolic/toxic products and bacteriocidins
three types of microbiota?
resident, transient, colonzation
colonization?
establishment of microbial population
acquisition of a new organism
flora in utero?
we are sterile
develop flora through birth canal, breast feeding, bottle feeding
facultative flora - acquired from oral exposure to feces
strict anaerobes can colonize only after sufficient facultative organisms are established enough that oxygen concentration are maintained at reduced levels
two basic mechanisms of pathogens?
invasion of tissue
production of toxins
transient normal flora?
from travelexposure to abnormal environment
different ways to invade host tissue?
capsule
adaptations
extracellular enzymes that degrade host tissues
invasiveness
ability to invade host tissues
LD50
percent dead vs. dose
measure of virulence
dose to kill half population
ID50
virulence
combination of invasiveness and toxigenicity
factors involved in the communicability of a disease?
source (both dormant and latent (carriers))
number of agents released by host
capability of surviving the transit (host to host
)percent of host susceptible to agent
ID50 - infected vs. dose
ID50
infected vs. dose
dose require to infect half population
communicability
transmission of infectious disease
exotoxins
secreted protieins
are heat labile
found mostly in gram-positive
what is found in gram-positive cells?
exotoxins
example –> TSS syndrome exotoxins
endotoxins
complex polysaccharides (LPS) that are part of bacterial cell wall-released when cell lysis occurs
generally heat stable
found in gram negative bacteria
toxigenicity
production of toxins
pathogenic process?
adhere
evade local immunity
replicate
evade systemic immunity
must escape body for transmission to new host
what is found in gram-negative cells?
endotoxins
intracellular pathogens produce?
chronic disease
what are the stages of infection?
incubation (virus or bacteria is replicating)
prodrome (non-specific symptoms)
specific-illness (have characteristic signs/symptoms)
recovery
latent infections
prodrome period
stage of infection where you have non-specific illnesses
viruses
are obligate intracellular parasites
may be either DNA or RNA (single or double stranded)
surrounded by protein capsid
some viruses have envelope -from host cell
virus replication
must attach to host cell
gets in
bunch of shit happens.
uncoating releases the viral gneome to be replicated
new viral proteins are packaged and released
non-enveloped virus entry to cell?
pinocytosis or translocation
enveloped virus entry to cell?
fusion b/c the envelope is a phopholipid layer
extracellular pathogens produce?
acute disease
cytolytic infection
viral infection leading to cell lysis and release of large numbers of visions
abortive infections
virus infects a cell that doesn’t permit its replication
rhinovirus
most common viral infective agent-common cold
persistent infections
viral infection that my be productive, latent, or transforming
rhinovirus structure
single strand positive sense RNA and capsid
no envelope
two modes of transmission for rhinovirus?
aerosol of respiratory dropletscontaminated surface
viral proteins of rhinovirus?
proteins transcribed as single, long polypeptide and cleaved into structural and nonstructural viral proteins