EXAM 4 TOPICS Flashcards
What is MIC
minimum inhibitory concentration
How do you determine MIC
where there is no growth
What does the kirby bauer tells us
which has the zone of inhibition and therefore is susceptible to being treated
Define intrinsic resistance
cells have an innate or natural resistance to a drug
Define tolerance or situational resistance
a usually susceptible cell is in an environmental situation where it is no longer as susceptible to the drug
Define aquired resistance
permanent, genetically encoded resistance to an antimicrobial drug
How does acquired resistance occur
through natural selection and mutations
What type of pathogen is S. aureus
human oppurtonistic pathogen
What’s a human oppurtonistic pathogen
can cause disease by penetrating a break in the skin or through mucous membrane
What is S. aureus susceptible to
penicillin
What is MRSA resistant to all
beta lactams AKA nosocomial
what are the two mechanisms of resistance to beta lactams by MRSA and other bacteria
- alternative enzyme PBPZA –> Marjority of MRSA
- Beta lactamases inactivating enzymes
What is PBP2
new transpeptidase that helps form the bacterial cell wall; has low affinity for antibiotics so it enables normal cell wall synthesis even in the presence of penicillin and the bacteria can grow and replicate as normal
PBP2–>
alternative enzyme: expression of new transpeptidase PBP2 with LOW affinity to beta lactams
What do beta lactamases –>
inactivating enzymes; enzymatic inactivation of drug by beta lactamases
What is beta lactamases
enzyme produced that secreted by bactera that degrade all beta lactam structure; so cells are resistant to its affects on cell wall synthesis
What are the treatment options for bacterial infections with beta lactamases resistance
cocktail treatmetn with Clavulanate, an inhibitor of beta lactamses
What are the 5 mechanisms for microbes to acquire antibiotic resistance
prudent antibiotic prescription and patient compliance
surveillance to limit spread, prevention measures
development of new drug
combo therapy
infection control by other methods
What are the 5 ways that microbes get acquired resistance
increase efflux
decrease uptake
target alteration
alternative enzyme
inactivating enzymes
What is the significance of vitamin deficiency in some animals
microbes can be a significant nutritional source of vitamin
What is the significance of underdevelopment of immune system in most animals
microbes are needed to stimulate development of certain host defenses
What is the significance of heightened susceptibility to enteric pathogens and fungal infections
normal bacterial residents are antagonistic against pathogens
What is the significance of less body fat
normal microbiota help to break down indigestible carbohydrates and increased fat storage in the body
What are the phases of infection
- portal of entry
- attach to host
- invading host
- infection
- portal of exit
What is the incubation period
time from initial contact with the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficient to cause symptoms
What is the prodromal stagw
vague feelings of discomfort; nonspecific complains
What is the period of invasion
multiplies at high levels, becomes well established, more specific signs and symptoms
What is the covalescent period
as person begins to respond to the infection, symptoms decline.
What is measles portal of entrance
respiratory
What is small pox portal of entrance
respiratory
What is the portal of entrance for anthrax
respiratory; cutaneous
What is the portal of entrance for salmonella
ingestion
________ _____ not only contribute to the ability of microbes to evade host defense and enter into the host tissue to grow and become establish
virulence factors
Virulence factors directly contribute to wha
tissue damage hence the severity of disease
What can microbes encounter resistance from
host defenses and human microbiota
What is the initial response when someone invades the host
WBC called phagocytes
What occurs with blocked phagocytic response
a bacterial cell will excrete surface slime layer that makes it physically difficult for phagocyte to engulf them
What does the portal of exit mean
transmission of disease to a new host
What is an incubation carrier
spread during the incubation period
What is a convalescent carrier
recuperating without symptoms
what is a chronic carrier
individual who shelters the infectious agent for a long period
What are the direct transmission of infectious disease
contact
respiratory droplet
vertical (mother to child)
biological vector
What are the indirect transmission of infectious disease
fomites
food and waste
airborne (droplet or aerosols)
where does ebola replicate in the host cell
cytoplasm–ssrNA virus that infects human cells
How does ebola spread
through direct contact with fluids
What is the portal of entry for ebola
mucous membranes
skin
cuts
What needs to occur before the nurses can release a patient from ebola isolation
microbial load must be below a threshold detection level
symptom free
What is a nosocomial infection
infection acquired during a hospital visit that was not there originally
What are the physical barriers of innate immunity
skin cemented together with keratin
mucous membranes
flushing
What do lysozymes do
antimicrobial because they cleave PT resulting in osmotic lysis of bacterial cells
What does dermicidin do for chemical innate defens
skill cells produce dermicidin that helps eliminate bacteria
What are cytokines
signalling proteins for immune system
What are the 3 types of cytokines
interluekins
chemokines
interferons
What are interleukins
modulate almost every function of the immune system
What are chemokines
recruit leukocytes to the site of infection, tissue damage, and inflammation
What do interferons do
important in our defense against viruses by interfering with viral replication
What are the 3 things the stem cells differentiate into for blood
RBC
WBC
platelets
What do WBC differentiate into further
monocytes
neutrophils
immune cells involved in adaptive immunity (B, T, and NK cells)
What is the purpose of neutrophils
phagocytes that are active engulfers and killers of bacteria
What do monocytes further differentiate into
macrophages and dendritic cells
What are macrophages and dendritic cells also
Antigen-presenting cells
Are WBC non specific
yes
Malaria spreads via vector; what is that
an animal or insect that transmit a pathogen from host to host
What is the mechanism of paslmodium flaciparum aka malaria
infect RBC
What group has natural immunity to malaria
sickle cell trait
What are the challenges of treating malaria
control mosquito
control parasite growth
Leukocytes display special molecules on their membranes known as PRRs which recognize what
PAMP
What do PAMPs act as
a red flag to signal WBC
What is phagocytosis
ingestion and destruction by WBC
What is thymus and bone marrow
primary lymph tissue
What is the spleen responsible for
filtering blood
What is the function of the lymph nodes
to filter the lymph fluid
How does lymph get into the systemic system
lymph continues to trickle from the lymph nodes via efferent ducts into system of larger drainage vessels, which connects to large veins near the heart
Cells and products of immunity can do what due to the close relationship of lymphatic system and circulatory system
continually enter the regular circulation
Cells involved in innate immunity are called _______ and form
WBC or leukocytes; stem cells
WBC have ________ on their surface that recognize many microbes by their PAMP
PRR
Through the process __________ the WBC internalizes foreign material or pathogens and destroy them
phagocytosis
After phagocytosis, ___________ expel debris and die, whereas ______________ present an antigen derived from the degraded material
neutrophils; macrophages and dendritic cells
What will reset the hypothalamus to increase body temperature
pyrogen
What are the two benefits of fever
increase temp to make the growth conditions less favorable
stimulates immune system further
Unlike innate immunity adaptive immunity responses are tailored to
specific threats that are not self–antigens
Unlike innate immunity adaptive immunity response time ________ with subsequent exposure to a pathogen while innate is the _______ everytime
shortens; same
The cardinal signes of inflammation: what does SHARP stand for
SWELLING
HEAT
ALTERED FUNCTION
REDNESS
PAIN
________ immunity discriminates well between self and non-self while ________ acts indiscriminately
adaptive; innate
______ is made up of classes of identical cells; ________ enormous diversity that can recognize trillions of antigens
innate; adaptive
_________ is made of the same type of response to each pathogen; ________ is specific and unique response to each pathogen
innate; adaptive
________ remembers previous exposure to antigens to mount stronger subsequent response while _________ has no memory of previous exposure
adaptive; innate
What are the two features of adaptive immunity that is very different from innate immunity
specificity and memory
_________ help with specificity
antibodies
_____ help with memory
lymphocytes
Define antigen
molecules that are recognized by T cells or B cells and have very specific interaction
Good antigens tend to be _________ while poor antigens include
complex molecule; small, simple molecules not attached to a carrier molecule and simple large molecules
What do b cells do in the cooperation between lymphocytes during antigen presentation
B cells assist in the production and actions of antibodies in response to the antigen–APC
what do t cells do in the cooperation between lymphocytes during the antigen presentation
respond to the APC’s
B cell receptors are called ________ and they bind __________
antibodies; antigens
T cell receptors bind _________ molecules that present antigens
MHC–2 receptors with an antigen
What do t cells release
cytokines, can induce lysis or apoptosis, can stimulate beta cell maturation
Where do t cells mature and then migrate
full maturation in the thymus gland, then migrate to the lymphoid organs
Where are CD4 on
t helper cells
Where are CD8 on
T cytotoxic cells
What are the examples of antigen presenting cells
dendritic cells
macrophages
B cells
What do CD8 cytotoxic t cells do
recognize MHC 2 and antigen and target the cell for destruction
What do CD4 t helper cells do
recognize MHC-2 and antigen to trigger cytokine production
What do CD4 T memory cells do
protect against future encounters with the same antigen
What is natural immunity
acquired as part of normal life experience
What is artificial immunity
acquired through medical procedures like a vaccine (also called immunization)
What is active immunity
a person develops their own immune response to an antigen that stimulates production of antibodies to create memory cells and takes time but is lasting
What is passive immunity
pre formed antibodies are made by one individual and donated to another individual; does not create memory, acts immediately and is short term
What do vaccines do
train our body to recognize and fight the disease if we encounter it in the future
If only a portion of a pathogen is being used as the basis for a vaccine, it would be an
acellular vaccine
What is a recombinant vaccine
from genetic material
What is a killed vaccine
from killed cell or inativated virus
What is an attenuated vaccine
live cells and viruses
