Chapter 16
when microbe establishes itself and multiplies in a particular environment
colonization
microbes that show no known beneficial relationship to humans; benign
commensalism
cause histamine release leading to vasodilation and neutrophil chemotaxis and accumulation leading to inflammation
complement cascade
stage of infectious disease cycle of recovery and recuperation
convalescence
normal microbiota excludes pathogens by
covering binding sites for attachment, consuming nutrients, producing compounds toxic to other bacteria
exotoxins are synthesized in the
cytoplasm
toxins that interfere with essential cellular mechanisms/ lyse cells
cytotoxins
___ are able to penetrate body's first line of defenses and then multiply in host tissue
invasive pathogens
hyaluronidase enzyme viral pathway
invasive pathogens reach epithelial surface, pathogens produce hyaluronidase, pathogens invade deeper tissues
provided a foundation for establishing that a given microbe causes a specific disease
koch's postulates
general mechanism used by protozoa and helminths to avoid antibodies
live inside host cells
pathogens can hide within ___ and avoid antibodies, control part of immune response and be transported
macrophages
to avoid destruction by the complement system microbes must be able to inactivate or avoid formation of
membrane attack complex (MAC)
cytotoxins that disrupt eukaryotic cytoplasmic membranes, causing the cell to lyse
membrane-damaging toxins
when a pathogen disguises itself by coating its surface with molecules that are similar to those found in the host
molecular mimicry
methods viruses use to avoid antibodies
move from cell to cell, force fusion of cells (syncytium formation)
most invasive pathogens enter tissues via
mucous membranes
mutual benefit between microbes and human host
mutualism
toxins that affect the nervous system
neurotoxins
an ___ pathogen only causes disease when body's innate/adaptive responses are compromised
opportunistic
relationship benefits microbes but harms human host
parasitism
suites of genes encoding for virulence
pathogenicity islands
unlike other microbes, ___ have the ability to overcome host innate and adaptive immune response and cause damage
pathogens
coagulase enzyme viral pathway
pathogens produce coagulase, blood clot forms around pathogens, pathogens produce streptokinase dissolving clot and releasing bacteria
can cause symptoms similar to the release of an endotoxin; systemic response leads to septic shock
peptidoglycan
toxin that hydrolyzes phospholipids in the cytoplasmic membrane
phospholipases
exotoxin that destroys membrane integrity
phospholipid hydrolyzing phospholipase
damage membranes by inserting themselves into the phospholipid bilayer, forming channels that allow fluids to enter the cell
pore-forming toxins
microbe that causes disease in otherwise healthy individuals
primary pathogen
period of early vague symptoms
prodromal phase
when monocytes or macrophages interact with LPS molecule what can happen
production of cytokines which stimulate production of prostaglandins and leukotrienes, activation of complement cascade, activation of coagulation cascade to stimulate bradykinin release
microbiota that are only in body area for temporary amount of time
transient microbiota
life cycle of microbial pathogens
transmission, adherence to human host, invasion, reproduction/exit, survival, transmission
TTSS stands for
type three secretion system
presence of free viral particles in the blood
viremia
traits of a microbe that specifically allow it to cause disease
virulence factors
beta hemolysis produces a ___ color
yellow
3 parts of host defenses detect and eliminate viruses
interferon, apoptosis, antibodies
presence of toxins circulating the bloodstream
toxemia
koch's postulates
1. microorganism must be present in every case of disease but not in healthy hosts 2. microorganism must be grown in pure culture from diseased hosts 3. the same disease must be produced when a pure culture of the microorganism is introduced into susceptible host 4. same microorganism must be recovered from experimentally infected hosts
in AB toxins which part is toxic
A
stages of phagocytosis
chemotaxis, recognition/attachment, engulfment, fusion of phagosome with lysosomes
in AB toxins which part is a targeting piece that binds to specific receptors on target cell
B
lipopolysaccharides can affect which cells of the immune system?
B cells, macrophages, monocytes
degrades complement component C5a
C5a peptidase
first used to link Bacillus anthracis with disease anthrax
Koch's postulates
specialized cell of mucosa-associated lymphoid tissues (MALT) that samples materials from intestinal mucosa and can exploited by pathogens to cross membranes
M cells
when oral antibiotics inhibit normal intestinal microbiota what grows in response
clostridium difficile
lipopolysaccharide structure
O side chain, core polysaccharide, lipid A
after adherence, inject toxins that reorganize actin filaments causing loss of microvilli allowing toxin to enter cell
TTSS
allows certain toxins to be injected into host cell
TTSS
types of membrane disrupting exotoxins
channel forming (pore-forming) and phospholipid hydrolyzing phospholipase
exotoxin that inserts itself into normal host cell membranes
channel forming exotoxin
what effects the length of the incubation period?
age of individual, host's physical condition, growth rate of pathogen, number of infectious particles encountered
suspension of exotoxin-neutralizing antibodies used to treat exotoxin-induced diseases
antitoxin
presence of bacteria in the bloodstream
bacteremia
TTSS is similar to
bacterial flagella
function in coagulation, thrombosis and can lead to internal bleeding
bradykinin
produced by coagulation cascade
bradykinin
the toxic LPS molecule from gram-negative bacteria is a ____
endotoxin
unlike bacterial cells, a virus must ___ to cause disease
enter host cell
toxins that cause symptoms associated with intestinal disturbance
enterotoxins
type of toxin inactivated by heat
exotoxin
toxic secreted enzymes are ____
exotoxins
true or false: macrophages are the only way to kill shigella cells
false; they survive when engulfed by macrophages
bacterial source of exotoxins
gram + and gram - bacteria
bacterial source of endotoxins
gram - bacteria
alpha hemolysis produces a ___ color
green
molecules that lyse red blood cells
hemolysins
time between exposure to pathogen and onset of physical illness
incubation period
progression of infectious disease
incubation period, illness, convalescence
LPS net effect is to
induce inflammation, fever, intravascular coagulation, hemorrhage, and shock
a microbe establishing itself onto a body surface and into a parasitic relationship with its host
infection
when relationship between microbe and host is parasitic it is called an
infection
number of microbes necessary to establish an infection
infectious dose
by forming actin tails certain bacteria can __ themselves from the interior of one cell directly into the interior of an adjacent cell. This lets the bacteria __ extracellular immune response mechanisms
propel; avoid
powerful mediators of inflammation, fever, and septic shock
prostaglandins and leukotrienes
produced by cytokines
prostaglandins and leukotrienes
beneficial roles of normal microbiota
protecting against infection, promoting oral tolerance, aiding digestion, producing substances important for human health
exotoxins are what kind of molecule?
protein
used by staphylococcus aureus as a strategy to avoid antibody adhesion and phagocytosis
protein A
within an epithelial cell, ____ cells propel and force themselves into the next cell
shigella
if scarring from inflammatory response damages inner areas of fallopian tubes in female reproductive tract there is a higher likelihood of
sterility due to blocking of fertilization and ectopic pregnancy
virulence factors
structural features, exotoxins, endotoxins
when symptoms do not appear or are mild enough to go unnoticed
subclinical
exotoxins that activate too many effector helper T cells causing a massive release of cytokines that leads to fever, nausea, etc
superantigens
___ and subjective because only the patient can feel them and ___ are objective because the doctors can notice them
symptoms; signs