Pathophysiology I Flashcards
What are the three categories of infectious diseases?
established infectious disease
newly emerging infectious disease
reemerging infectious disease
what are established infectious disease?
endemic diseases that have been prevalent for a sufficient perioud of time to allow for a relatively stable and predictable level of morbity and mortality
what are newly emerging infectious diseases?
diseases that are recognized in the human host for the first time
what are reemerging infectious diseases?
diseases that historically have infected humans but continue to reappear in either new locations or resistant forms or reappear after apparent control or elimination or under unusual circumstances
what is the definition of infectious disease?
disorder in which tissue damage or dysfunction is produced by a microorganisms
direct damage causes by microorganisms, or defense mechanisms to eliminate infection
what are ways that microorganisms of infectious disease can transmission
person to person = contagious
or other sources, vectors, reservoirs including: animals, insects, soil, water, food, microbial flora
what is the complex of properties that allows an organism to achieve infection and cause disease of different degrees of severity
virulence
How do virulence factors enable organism to achieve infection and cause disease by:
gaining access to the body
avoiding multiple host defenses
accommodating growth in human milieu
parasitizing human resources
inducing damage or toxicity
What are the defense mechanisms of the host?
skin
mucous membranes
filtration system of upper respiratory airways
mucociliary escalator
antimicrobial secretions
lymphatic and immune systems
What are host factors in infectious disease?
historical notion
heritable variability
age
previous exposures
integrity of host defenses
behavior
What are infectious agents?
viruses
prions
bacteria
fungi
protozoa
helminths
What are different types and onsets of infectious disease?
acute
chronic
local
systemic
What are the different possible locations and compartments of infection?
respiratory system - upper and lower
dental
digestive - enteritis and peritonitis
urogenital
skin
bone and joint
central nervous system
blood
The smallest livings cells are known as
bacteria
what is the typical size of bacteria?
0.1 -10 um
bacteria are also known as
prokaryotes
how are bacteria classified?
based on structural features of the outer envelope
Most bacteria have a
rigid cell wall
What is the name of the gram stain used to classify bacteria?
crystal violet - iodine complex
What are some key characteristics of gram positive bacteria?
dark blue stain does not wash out
cell wall contains teichoic acid and thick peptidoglycan layer
What are some key characteristics of gram negative bacteria?
stain washes out and counter stains with safranin
outer membrane contains a lipopolysaccharide component (LPS)
What is an endotoxin, that is a potent mediator of shock?
LPS
T or F. the dark blue stain does not wash out in gram positive bacteria
T
T or F. the stain does not wash out in gram negative bacteria
F. the stain does wash out and safranin is used to stain red/pink
What are the types of bacterial shapes?
cocci
bacilli
vibros
spirochetes
what bacteria shape are rods
bacilli
what bacteria shape are spherical or round?
cocci
what bacteria shape are curved?
vibros
Which bacteria shape are spiral shaped?
spirochetes
The different types of classifications for bacteria are?
gram stain
shape
colony characteristics
metabolic requirements
biochemical components
genetics
what are the different types of metabolic requirements for bacteria?
aerobic
anaerobic
faculative
What are the different types of biochemical components for bacteria?
coagulase
catalase
hemolytic
How do bacteria cause disease?
direct destruction of tissue
release of toxins
stimulation of host response
What is released during the acute phase of bacteria causing disease?
IL1 IL6 TNF
do all bacteria cause disease?
no
what is the function of normal flora?
aid in digestion
produce vitamins
friendly bacteria protect pathogens by forming a barrier and fighting for available nutrients
T or F Normal flora that invade sterile sites cannot cause disease
false. they can cause disease
___________ have mechanism that promote growth at the hosts expense
virulent bacteria
____________ take advantage of preexisting conditions that enhance susceptibility
opportunistic bacteria
What are some examples of conditions for opportunistic bacteria?
immunosuppression such as burn or HIV patients
breaches in skin
What are the two major factors that determine the occurrence of a disease?
Bacterial strain
inoculum size
T or F inoculum size varies greatly among bacteria
T
T or F inoculum size is not influenced by pH or congenital defects
F. it is
T or F bacteria possess different degrees of virulence
T
What are different areas of the body into which bacteria may gain entry?
mouth
nose
respiratory tract
ears
eyes
urogenital tract
anus
breaches in skin
external or internal wounds
T or F The GI tract is naturally colonized by benign and potentially helpful bacteria
T. normal gut flora
T or F Environmental conditions may determine what bacteria can or will colonize at a body site
T
Sterile body sites may be colonized by bacteria if there
is a breach of the bodys defenses or a new portal of entry such as a puncture
Pseudomonas aeruginosa infection in CF is due to reduction in _____________
mucociliary function and altered secretions
are mechanisms used by bacteria to adhere to and colonize body surfaces general or specifc?
specific
bacteria are not washed away due to the fact that they…
adhere to blood vessels, bladder walls or endothelial lining
e.coli and other bacteria have ________- that bind to specific tissue receptors
adhesions
many adhesions are present on the tips of bacterial _____________
fimbriae (pilli)
How do streptococcus pyogenes adhere?
using lipoteichoic acid and F protein to bind to epithelial cells
______ and ______ express adhesions that are not on fimbriae
bordetella pertussis and mycoplasma pneumoniae
bacterial adhesions of neisseria gonorrhoeae are
fimbriae which binds to oligosaccharide receptors on epithelial cells
What are the bacterial adhesions of E coli?
p fimbriae
binds receptors for - d - falactosyl - - d galactoside which is present on p blood group antgen on erythrocytes and uroepi cells
_____ are a special adaptation that facilitates colonization
biofilms
biofilms are bound within a sticky web of _____
polysaccharide
________ sense when cell number is sufficient to produce a biofilm and create a bacterial communtity
pseudomonas aeruginosa
what is an example of a biofilm?
dental plaque
what is the function of biofilms?
they protect bacteria from host defenses
bacteria are unable to cross skin but some can
cross mucosal membranes
invasive bacteria either _____ or _____
destroy the barrier
penetrate barrier cells
what are the three types of bacteria that use fimbriae to bind micofold cells of the colon that stimulate cell membrane to engulf the bacteria?
shigella
salmonella
yersinia
what type of bacteria in terms of penetration can spread to adjacent cells?
shigella
what type of bacteria in terms of penetration can pass through the cell and initiate a systemic infection?
salmonella
what are pathogenicity islands?
large chromosomal regions that contain sets of genes encoding virulence factors
T or F genes of a pathogenicity island may be turned on by a single stimulus such as pH or heat
True
what two bacteria encode protein machinery for invasion within pathogenicity islands in DNA?
salmonella sp
enteropathogenic strains of e colo
what are some by products of bacterial growth?
acids, gas and other toxic substances
also degradative enzymes
what is a by product of clostridum perfringens after it establishes infection in O2 depleted tissue?
gas gangrene
bacterial products that directly harm tissue or trigger destruction are known as
toxins
what are the causes of toxin and toxin like activities?
degradative enzymes that cause lysis of cells and receptor binding protein initiate toxic reactions in target cells
______ components initiate systemic responses due to release of cytokines
cell wall
What is presented in food contaminates and can cause symptoms before an organism even begins growing? What are two examples of bacteria in which this can be found?
preformed toxins
staph aureus and bacillus cereus
T or F bacterial cell wall components cannot elicit a host response
False. They can
What components of the bacterial cell wall can bind to toll like receptors on myeloid cells and stimulate cytokines?
pathogen associated molecular patterns (PAMPS)
in gram positive organisms, ____ , ____, and _____ are released and stimulate pyrogenic acute phase responses that are endotoxin like
peptidoglycan, teichoic acid , lipoteichoic acid
in gram negative organisms, lipopolysaccharide activates inflammatory reaction and it is known as a
endotoxin
What portion of LPS is responsible for endotoxin activity?
the lipid portion
Only gram ____ make endotoxin
negative