Exam 2 Flashcards
(257 cards)
1
Q
Factors to consider
A
Location, type & number of microbe, risk of infection
2
Q
Why control microbial growth?
A
To prevent diseases,
protect the food supply,
create clean areas for research & development
Remember that not all microbes are pathogens and most are beneficial
3
Q
By killing microbes
A
Cidal agents think “sui-“
4
Q
By inhibiting microbial growth
A
Static agent
“inhibit” meaning that the bacteria stops growing BUT does not kill them. Static=electricity=shocks (things don’t move when they’re shocked)
5
Q
Bactercidal
A
To kill bacteria
6
Q
Sterilization
A
Removing all microbial life
Does not consider prions
7
Q
Disinfection
A
Destroying harmful microbes on a surface or object
Some microbes will remain
8
Q
Disinfectant
A
Chemicals used for disinfecting inanimate objects
9
Q
Antiseptics
A
Destroy harmful microbes on living tissues/people
used on patients before invasive procedure
10
Q
Asepsis
A
Free of microbial contamination
11
Q
Aseptic techniques
A
Prevention of contamination through procedures
12
Q
Decontamination
A
Reduces the number of pathogens to a safer level
13
Q
Sanitation
A
Substantially reducing the microbial population to meet health standards
14
Q
Pasteurization
A
Brief heating to reduce the number of spoilage microbes and destroy pathogens without changing the characteristics of the product
15
Q
Preservation is a form of [?] method
A
bacteriostatic method inhibits the growth of bacteria but does not kill the bacteria
16
Q
Preservation
A
A process of delaying spoilage
example would be refrigeration, which uses temperature to slow the growth of bacteria.
Chemical preservatives can be added to slow growth even further
17
Q
Approaches to microbial growth
A
Depends on the situation: daily life, setting, laboratories, food production facilities, water treatment plants, and any other industries.
18
Q
Daily life requirements for microbial control
A
Washing and soaping and scrubbing and detergent
19
Q
most frequently misses spots when handwashing
A
under the nails, wrists, around, jewelry,
20
Q
how does soap work to remove microbes during handwashing
A
nonpolar tails of micelle soap adhere to the dirt on the skin. Polar groups are soluble in water and help lift the dirt away from the skin
21
Q
Soap is beneficial to skin microbiota because
A
the skin is not affected by regular use given that they reside deeper in underlying layers of skin
22
Q
BSL4
A
lethal pathogen for which no vaccine or treatment is available
23
Q
BSL-1
A
Microbes is not know to cause disease
24
Q
Washing your hands
A
Soap aids in the mechanical removal of microbes
The most important step in stopping the spread of many infectious diseases
25
Health care associated infection HAIS
Patients are often more susceptible to infection due to their weakened condition
Patients may undergo invasive procedures cutting intact skin which exposes it to pathogens
Pathogens are more likely to be found in hospitals (feces, ventilation)
Operating rooms must be monitored
Surgical instruments must be sterilized
Prions are a relatively new concern and are very difficult to destroy
26
Microbial laboratory
Aseptic technique
Sterilization if materials cdc guideline
Bio safety levels range from BSL1-4 (1 microbes not know to cause disease)
(4 being lethal pathogens with no vaccine or treatment existing)
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Food preparation
Perishables retain quality longer when contaminating microbes are destroyed removed or inhibited
Heat treatment (most common), irradiation (kill microbes) chemical additives (prevent growth)
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Water filtration
Ensure that drinking water is free of pathogens
Uses filtration and chemical methods
Chlorine is traditionally used to disinfect water
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Selection of an effective antimicrobial procedure depends on
The type and number of microbes
Environmental condition
Risk of infection
Composition of the item being treated
Length of exposure needed
Cost and availability
Toxicity
30
Microbes resistant to treatment
Bacterial endospore
Only extreme heat and chemical treatment destroy them
Protozoa cyst and oocytes
Resistant to disinfection but susceptible to boiling
Mycobacterium species
Pseudomonas species
Resistant to disinfectants and can even grow in some of them
Enveloped and non enveloped
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Decimal reduction time
time required to kill 90% of populations under specific conditions
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temperature and Ph can
influence effectiveness of disinfectants
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microorganisms in [?} are more resistant to any anti-microbial treatment
biofilm
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Bleach is more effective at [?] ph
low
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Dirt grease and body fluids
Can interfere with heat penetration action of chemicals
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Risk for infection categories for medical instruments
Critical= must be sterile (direct body tissues)
Semi critical= must be free of viruses and vegetative bacteria (contact mucous membrane but not body tissues)
Non critical= pose a low risk of transmission (contact unbroken skin only)
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Actions of antimicrobial agents
alteration of membrane permeability
damage proteins
damage nucleic acids
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how does heat kill microbes
the cytoplasmic membrane is disrupted/ damaged
proteins and enzymes are denatured
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Heat treatment is the best
and most useful methods for microbial control
can only be used to disinfect or sterilize
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Types of heat
Moist heat=destroys microbes by irreversibly denaturing their proteins
Dry heat= less efficient than moist heat at killing microbes; requires longer times and higher temperatures
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Moist heat
Boiling (100C) after 5 minutes bacteria is killed
Pasteurization; heating to a high temperature for a short time// does not sterilize
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Dry heat
less effective because it takes longer times and higher temperatures
Incineration= components to ashes
Hot air oven= destroy cell components and irreversibly denature proteins
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Autoclave
used to sterilize surgical instruments- increase pressure raises the stream temperature
kills endospores
can destroy prions
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Commercial canning
uses an industrial size autoclave called retort//designed to destroy clostridium botulinum endospores
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Low temperature
inhibits growth-bacteriostatic
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Desiccation
removes water, prevent metabolism,
microbes may remain visible but are dormant for years
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Osmotic pressure
high sugar/salt causes plasmolysis and inhibits metabolism
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Surface tension depressants
soaps, detergents (loosens contamination from surfaces
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Filtration
uses a membrane filter to remove microbes
membrane filters have microscopic pores that allow liquid to pass through
in air, High-efficiency particle air (HEPA) is used to remove airborne particeles
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Radiation
can be used to destroy microbes
ultraviolet, ionizing, and microwaves are types of radiation
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limitations to ultraviolet radiation
bacterial endospores are resistant to UV lights
poor penetrating power- only kills microbes on the surface
must be used carefully since it can cause skin cancer and damage retina
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ultraviolet radiation
destroy microbes by damaging their DNA
UV light is absorbed by microbial DNA causing thymine dimers to form in DNA
used to destroy microbes in air, water and hard surfaces
UV light is most effective in close range against exposed microorganisms
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Ionizing radiation
x rays, gamma rays
damage skin cells
used to sterilize heat-sensitive materials such as foods
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Microwave
low energy wave that does not have a direct effect on microbes
microwaves kill by generating heat via water molecules
cook food unevenly
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High pressure processing
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Types of physical antimicrobial methods
Heat treatments
Moist heat, dry heat
Filtrations
Radiation
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Soap aids in
Mechanical removal of microbes thorough handwashing
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Transient
Pathogens not related to our microbe
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Temperatures to kill microbe
Cytoplasmic
Denatured
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Autoclave
121°C at, 15 min
131°C for 1 hr for endospores
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Ultra violet radiation
Alters DNA
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Germicide
Chemicals used to disinfect & in some cases sterilize (kills microorganisms & inactivates viruses
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Sterilants
destroy all microbes including endospores and viruses; used to treat heat-sensitive critical instruments
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Disinfection
elimination of microbes from inanimate objects
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Disinfectants
agent used to eliminate microbes from inanimate objects
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Antiseptic
an agent that kills or inhibits growth of microbes and is non-toxic enough to use be used on human tissue
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Sanitation
an agent that reduces microbial numbers to safer levels
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Considerations when selecting the appropriate germicide
Toxicity )
Length of contact required (contact time)
Concentration
Types & number of microbes present
Activity in presence of organic material
Comparability with materials being treated
Residues
Cost & availability
=~
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Actions of antimicrobial agents can be achieved
through physical control methods and chemical
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why 100% alcohol does not work
proteins are more soluble and denature easily in alcohol mixed with water
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limitations to alcohols
does not reliably destroy endospores and some non-eveloped virus
evaporates quickly, limiting contact time
can damage rubber, some plastics
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Alcohol
Quickly kills vegetative bacteria & fungi
70% is used in hospitals & laboratories
Proteins are more soluable & denature more easily
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Soap & water vs hand sanitizer
water reduces the amounts of all types of germs
60% hand sanitizer is recommended
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Halogens
Chlorine & iodine
Common disinfectants that damage proteins & cellular components
limitations include being too irritating to the skin and mucous membrane to be used as an antiseptic
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Chlorine
disinfectant
very low levels are used to disinfect drinking water
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Iodine
antiseptic; kills vegetative cells, unreliable or endospores
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What is added to water to disinfect
chlorine
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Peroxygens
Hydrogen peroxide
Powerful oxidizer used as sterilants
Germicide on living tissue
Leaves no residue
limitations; less effective/potentially irritating gon living tissues due to catalase activity
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Phonolics
Phenol one of the earliest disinfectants. kills most vegetative bacteria by destroying cytoplasmic membranes and denaturing proteins; not reliable on all viruses and endospores
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positive charge of quat attracts
negative charges on cell surface of microbes
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limitations to quats
can grow within the solutions
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Quats
Quaternary Ammonium Compounds// destroys vegetative bacteria and enveloped viruses but is not effective on endospores
disrupts the cells membrane and negatively charged proteins
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Ethylene oxide
destroys all microbes including endospores and viruses by chemically modifying proteins and nucleic acids
used to sterilize sensitive items (pacemakers, artificial hips. fabrics)
IS TOXIC
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Aldehydes
capable of destroying all microbes; inactivates proteins and nucleic acids
toxicity;carcinogens
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perishable products can be preserved by
chemical preservatives
low temperature storage
reducing the available water
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chemicals preservatives
weak organic acids (alter membrane function lower Ph) and nitrate and nitrite (inhibit endospore germination)
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Blacklights
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Thawing food
some microbial cells are killed by ice crystal formation but many survive and can grow once thawed
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reducing available water
adding sugar or salt which creates a hypertonic solution drawing water out of cell (plasmolysis)
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drying food
stops microbial growth, but does not kill it
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Discovery of antibodies
Alexander flaming identified mold
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Antimicrobial medication
Drug that inhibits the growth of or kills infectious microorganisms
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Antibiotics
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Antiviral
Drug that
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Characteristics to antimicrobial drugs
Selective toxicity to microbes
Antimicrobial action
Spectrum of antimicrobial activity
Tissue distribution, metabolism and excretion of
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therapeutic index
lowest dose that is toxic divided by the therapeutic dose (high TI is less toxic)
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Antimicrobial action
bactericidal: drug kills bacteria directly
bacteriostatic : inhibits bacterial growth
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Selective toxicity
drugs cause greater harm to microbes than to human hosts
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the spectrum of antimicrobial medication
broad-spectrum: gram-positive and gram-negative bacteria (disrupt normal microbiota. important for acute diseases
narrow spectrum: requires identification of pathogen and testing it for sensitivity
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Tissue distribution, metabolism, & excretion of drugs
antimicrobial behaviors differ in the body
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Route of administration
IV, IM, oral, tropical ect
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Drug combinations
Antagostnic: medications interfere with each other
Synergistic: one medication enhances another
Additive: combinations that are neither are additive
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Adverse effects
Allergies
Toxic side effect
Suppression of normal microbiote may lead to dysbiosis
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Target of antimicrobial drugs
cell wall synthesis
cell membrane
protein synthesis
nucleic acid synthesis
metabolic pathways
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Glycopeptide
vancomycin (last resort against MRSA)
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bacitracin
topical, triple antibiotic ointment
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Amoxicillin
Inhibits cell growth
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Beta lactam antibiotics
all have a Beta lactam ring
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medications that inhibit beta lactam
penicillin, cephalosporins, carbapenems, monobactam
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resistance methods used by bacteria against Beta lactams
beta-lactamases: some bacteria synthesize Beta-lactamase, which break down the beta-lactam ring
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types of beta lactamase
penicillinase (inactivates members of the penicillin family)
extended spectrum Beta-lactamases (inactivates a wide variety of beta lactam)
carbapenemases- inactivate the greatest number of beta lactams lead to carbapenem drug resistance
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How antibiotic resistance happens
Lots of germs
Little resistance
Antibiotics kills bacteria causing the illness as well as good bacteria protecting the body of the infection
The drug resistance bacteria are allowed to grow and take over
Some bacteria give their drug resistance to other bacteria causing bacteria
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Five general groups of penicillins
natural
penicillin resistant (methicillin)
broad spectrum (amoxicillin)
extended spectrum (ticaricillin)
pencillin + beta-lactamase (augmentin- amoxicillin+clavulanic acid)
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Mechanism of drug resistance
Blocking entry of drug
Inactivate the drug enzyme and interfere with drug
Alteration or drugs target molecule
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Inhibits protein synthesis by attaching to various subunits of the [?] 70s Ribosome
prokaryotic
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Pleuromutlins
prevents peptide bonds from being formed
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streptogramins
each interferes with a distinct step of protein synthesis
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Lincosamides
prevents the continuations of protein synthesis by binding 50s subunit
resists many antibiotics
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macrolides
prevent the continuation of protein synthesis by reversibly binding 50s subunit to prevent the translation from continuing
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chloramphenicol
prevents peptide bonds from being formed by binding to 50s ribosomal subunit and prevents peptide bonds between amino acids
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oxazolidinones
interfere with the initiation of protein synthesis
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tetracyclines and glycylines
block the attachment of tRNA to the ribosome
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Aminoglycosides
block the initiation of translation and cause the misreading of mRNA
irreversibly bind 30s ribosomal subunit
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Fluoroquinolones
inhibits topoisomerase 2 or gyrase
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Rifamycins
inhibits RNA synthesis by blocking prokaryotic RNA polymerase
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Metronidazole
binds DNA in anaerobic organisms only
anaerobic metabolism required to convert to active form
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Interfere with cytoplasmic membrane integrity
interfere with bacterial cytoplasmic membrane permeability or synthesis--> cell leakage and death
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Target Metabolic pathways
broad spectrum, bacteriostatic
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some antibiotics are folate inhibitors
acts as PABA substrate analogs to inhibit different folate pathways which produce nucleotides
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sulfonamides, trimethoprim
inhibit different steps in synthesis of folic acid and coenzyme required for nucleotide synthesis
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Sulfonamides and related are called
sulfa drugs
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amoxicillin
treats bacterial infection by inhibiting bacterial cell wall growth
amoxicillin binds to the transpeptidase active site
amoxicillin blocks transpeptidase activity
amoxicillin interrupts bacterial cross linking and cell wall synthesis
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Kirby baer disc diffusion test is routinely used to
determine susceptibility of a bacterial strain to antibiotics
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Blocking entry of drug
Decreased uptake of the meditation
Changes in porin protein of the outer membrane in gram negative bacteria
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Inactivation of drug by bacterial enzyme
Bacteria produces
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Alteration of drugs target molecules
Minor structural changes that affect binding
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Gram positive
Thick peptidoglycan layer absorbs
Surrounding layer absorbs surrounding
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Gram negative
Harder to kill
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Acquisition to resistance
Occur during DNA replication at a low rate but can have effect
In a population of 109 cells at least one will likely mutate
A single base pair change in a bacterial gene encoding a ribosomal proteins yields resistance to strepto
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Horizontal gene transfer
Genes encoding resistance Can spread to different strains
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R plasmids Can contain
Genes encoding for resistance to antimicrobial medications
Genes required for pilus synthesis
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Mechanism
Conjugation
Transduction
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Superbugs
Bacteria that is resistant to large numbers of antibiotics
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Multiple and extensive drug resistant mycobacterium tuberculosis
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Viruses
Obligate intracellular parasites
Not alive, acellular particles or agents
Not an organism
Not made up of cells
No metabolism, replication or motility
Hijack the host cells replications system to divide
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Can viruses divide outside is a living cell
No
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Viruses are ((n)) outside cells
Inert
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Smallest to largest
10 to 800nm
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All viruses have
Nucleic acid (Either DNA or RNA)
Capsid (protein coat)
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Some virus have
Spikes
Envelope (more vulnerable)
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Capsid
Protein coat that all virus’s have
Determines the shape of the virus
Protects the Nucleic acid
Capsid are protected
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Virus shape
Helical Ebola
Polyhedral adenovirus
Complex bacteriophages
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Virus envelope
No envelope= naked virus or non enveloped virus
Phospholipid bilayer membrane outside of the virus
Taken from host cell
Provide protection and attachments so it can hide from the immune system
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Naked vs enveloped
N
E
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Spikes
Glycoproteins
Outer surface protection
Important for attachment to the host cell
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Adenovirus
Polyhedral
Double stranded DNA
Non enveloped
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SARS CO V 2
Single stranded RNA
Helical
enveloped
Spikes glycoproteins
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For a virus to replicate multiply
It must invade the host cell
It must take over that hose metabolism machinery
Host are anything alive
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Virion
160
Modes of transmission
Direct transmission
Direct contact
Direct Spray
Indirect transmission
Airborne
Vehicle borne (fomite)
Vector borne carry the agent
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Entry for virus
Epithelial surface
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Viral taxonomy
-viridae
-virus
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Enteric virus
Oral fecal
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Zoonotic
Animals
165
Arbovirus
166
Animal virus
DNA or RNA
167
Animal virus cycle
Attachment
168
Bacteriophage
Virus that infects bacteria
Most numerous viruses on earth
important for ecology and evolution
Removes bacteria from ocean
Used as models for learning about animal virus
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Lytic
Phage causes lysis and death of the host bacteria cell
Attachment
Genome
synthesis phage genome is transcribed
Assembly
Release bacterial cell lyses
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Lysogenic
Phage DNA is incorporated into the host DNA
Attachment
Genome entry
Phage DNA is integrated into the hosts cells called prophage
Prophage replication
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Temprate phage
Lambda
Can alter
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Toxins are encoded by
Phage genes
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Exotoxins
Released from bacterial cell
Potent
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Clostridium tétani
Tetanus neurotoxin block nerve impulses
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Clostridium botulinum
Botulinum toxin causes food poisoning
Botox prevents nerve impulses
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Escherichia coli
177
Staphylococcus
178
Opportunistic infection
Disease that is caused by microbes that is not known to be harmful
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Primary pathogens
180
Skin and mucus membranes are barriers
Mutualism
Commercialism
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Acure
Short lived infection
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Chronic
Infection that develops slowly and last long
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Latent
Infection that is present but not causing symptoms
184
Exotoxin
Toxic protein produced by a microorganism
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Normal microbiota
Group of microorganism found growing in healthy individuals
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Resident microbiota
Inhabit sites for extended periods permanently colonize
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Transient microbiota
Inhabit temporary
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Human micro biome
Colonization at birth changes when c section and with vaginal delivery
Breastfeeding
Environment
Changes with lifestyle
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Normal microbiota benefits
Protects against pathogens cancer
Antibiotic exposure kills normal bacteria leads to dysbiosis
Simulation of adaptive immune system
Promotes immune system tolerance
Aids in Digestion
Produces substances important to human health
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Pathogenicity
The ability of an agent to cause disease
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Virulence
The degree of pathogenicity of an organism
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Virulence factors
Traits of a microbes that allow it cause disease genes can be transferred via horizontal gene transfer
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Communicable
Infectious disease that spread from one host to another
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Etiology
Cause of disease
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Incubation period
Time between introduction of microbes to host and onset of signs
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Convalescence
Recuperation
197
Carriers
Individuals who have recovered from the illness but still are capable of spreading disease
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Sign vs symptoms
Sign what you see
Symptom what you’re told
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Overview of the immune system
Collection of organs, tissues, and cells
Job is to guard the body against pathogen, abnormal malfunctioning cells,foreign cells or particles
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Adaptive immunity
activated by exposure to specific pathogens; continually develops over your lifetime as its exposed to specific pathogens
immunological memory
201
Innate immunity
routine protection present at birth non specific, quick response
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Thymus
T cells mature here
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Spleen
Filtering out blood
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Appendix
Lymphoid tissues
205
collectively, the main roles of the innate immune systems
prevent the entry of foreign material using physical and chemical barriers
prevent further spread of infection
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adaptive immunity
we are not born with , but is acquired throughout our lifetime T cells and B cells when exposed to specific antigens
acquire immunity
slower but very effective
"creates memory" through memory cells
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Immune tolerance
ability for the immune system to ignore normal self cells
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what is an antigen
foreign particle that the body recognizes as non self
adaptive is antigen-specific
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antigen presentation
requires the recognition of specific non self antigens during this process
210
antigens react specifically with antibody
B-cell and T cell receptors
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antigenic determinants (epitope)
binds to receptors
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immunological memory
the ability of the immune system to respond more rapidly to any pathogen or antigens that has been encountered previously
thanks to this, we can vaccinate against infectious disease and avoid through natural infection
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neutrophils
common leukocytes found in the blood
when injury and or microbial occurs they are alerted via chemotaxis, they are the first to leave blood stream
phagocytes, they kill via phagocytosis and live hours to a few days then undego apoptosis
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natural killer cells
innate immune system
derived from lymphoid stem cells so they are lymphocytes
recognizes the abnormality
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monocytes macrophages and dendritic cells function
as phagocytes and form an important first line of defense against harmful
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dendritic cells
phagocytes that live in blood or tissue
phagocytic and antigen-presenting cells
only connection between adaptive and innate
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lymphocytes
type of white blood cell (leukocyte)
derived from lymphoid stem cells
218
t cells
cell-mediated immunity
direct the immune response by helping to stimulate b cells
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B cells
humoral cells
220
humoral immunity
b cells mature in bone marrow, make antibodies, memory cells
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cell mediated immmunity
t cells mature in the thymus helpert T cells activate B cells
cytoxic t cells are directly involved in killing infected cells
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anatomy of the lymphatic system
secondary lymphoid organs contatn dense populations of lymphocytes and other immune cells
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secondary lymphoid organs
lymph nodes, spleen, tonsils/adenoids/, apendix
224
peyers patches
lymphoid tissue in intestinal wall
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cytotoxic t cells
directly involved in killing infected cells
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helper t cells
stimulate b cells towards antibody production; releases cytokines to stimulate other immune cells
227
regulatory t cells
regulate and suppress immune cells as needed; peripheral tolerance
228
memory t cells
can respond quickly upon re-exposure to the same antigen
229
naive lymphocyte
has never encountered an antigen
230
activated lymphocyte
received specific signals, proliferates produces proteins
231
effector lymphocytes
232
memory lymphocytes
233
lymphocytes receptors
b cells and t cells have membrane bound receptors
function is to recognize and bind specific antigens
234
b cell receptor
membrane version of the specific version of the specific antibody; binds free antigens
235
t cell receptor
236
antigen presenting cells
have receptors that bind antigens
237
major histocompatibility complex proteins
238
what cells are responsible for t cell activation
dendritic cells
239
Fluoroquinolones
inhibits topoisomerase 2 or gyrase
240
Rifamycins
inhibits RNA synthesis by blocking prokaryotic RNA polymerase
241
Humoral activity
antibody response
242
three antigen presenting cells
dendritic
macrophages
b cells
243
plasma cells
affector cells
244
cytochines
chemical signal from helper T-cells to plasma cell
245
B cell mature in
bone marrow
246
BCR genes
V ariable, D iverity J oining regions
247
Diversity is created through
gene diversity of VDJ genes on the light and heavy chains of b cell receptors
248
Central tolerance
process during development where B cells that bind to self-antigens are destroyed
249
peripheral tolerance
most mature b cells require signaling and confirmation from Helper t cells to begin making B cells
250
Naive B cells
mature B cell with functional BC that has not yet encountered an antigen
251
A naive b cell encounters an antigen
in secondary lymphoid organs
252
antigen binds to the
variable region of the b cells receptor
253
B cells internalizes processes and
presents antigen epitope on MHCII
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B cells presents antigen on MHCII to
Helper T cells (CD4)
255
Activated B cells proliferation and differentiate to form
effector B cells or plasma cells and memory B cells
256
Plasma Cells secrete
large quantities of antibodies that bind to the antigen
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memory B cells are long lived descendants of activated B cells
