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Microbio > Final Exam > Flashcards

Final Exam Flashcards

1
Q

What microbes are we trying to control

A

Pathogens
- mesophiles, nuetrophiles, and chemoorganotrophs

Essentially microbes that can live in:
Temp 20-40 C
Near neutral pH
Sea level
0.9% salt
Ample nutrients - organic molecules

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2
Q

Where does fear of microbes come from

A

Germ theory of disease

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3
Q

Relationship between clean, sterile, disinfected, and sanitation

A

Sterile, disinfected, sanitized doesn’t equal clean

Clean doesn’t equal sterile

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4
Q

Define clean

A

Removal of dirt, dust, food, grease, particles, feces, vomit, etc
- goal is not to remove microbes

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5
Q

Define sterile, disinfected, sanitized

A

Lowering number of microbes

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6
Q

List the control methods

A

Clean
Sterilization
Disinfection
Antisepsis
Sanitation

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7
Q

Describe sterilization

A

Removal of all living cells and endoscopes
- zero living things
- only apply this to inanimate objects
- zero microbes
- endoscopes are gone

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8
Q

Describe disinfection

A

Removal of microorganisms from inanimate surfaces
- does not include endoscopes (all survive) and some viruses
- lowering number of microbes
- takes longer than sterilization

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9
Q

Describe antisepsis

A

Removal of microorganisms from living tissues, such as skin or mucous membrane
- doesn’t include endoscopes and some viruses
- want to not damage the living tissue = gentle
- ex: washing hands

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10
Q

Describe sanitation

A

Reducing microbe numbers to “safe” levels
- “safe” = public health standard
- inanimate objects
- particular #
- ranges based on item and office

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11
Q

Describe antimicrobial chemical products for: disinfectant

A

Chemical compound that has the ability to eliminate, kill or remove microorganisms from inanimate surfaces
- bleach
- harsh
- lowers number in animate surfaces

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12
Q

Describe antimicrobial chemical products for: antiseptic

A

Chemical that is capable of eliminating or reducing microorganisms deposited on the surfaces of living and mucous tissues without damaging them
- gentle
- lowers number in living tissues

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13
Q

What product can be used for both disinfectant and antiseptic

A

Alcohol

Difficult for chemicals to be both

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14
Q

Define -cidal agents

A

Lethal effects

Bacteriocidal agents kill bacteria

Kills the prefix

Fungicides, virucides, algicides, etc
- kill fungi, kill virus, kill algae

Ex: heating food till burnt

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15
Q

Define -static agents

A

Slow or stop metabolism or reproduction

Bacteriostatic agents inhibit bacterial growth

inhibits the growth of the prefix

Fungistatic, virustatic, algistatic
- slow fungi, slow virus, slow algae

Ex: storing leftovers in the fridge

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16
Q

What are the external factors that influence microbial control

A

These factors will influence effectiveness

Population size
- more = take longer

Composition of the population
- what microbes are present

Concentration/dose of agent
- dose/dilution

Contact time
- exposure time

Location
- living tissue vs inanimate objects
- pH, dirt, etc impact

Temperature
- hot temp is faster

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17
Q

Describe Protozoa of medical interest

A

Have motility

They have two lifestyles
- trophozoites (active feeding)
- cysts (dormant stage)

Depends on Protozoa, which stage is infective

Some protozoa never form cysts, others alternate between the two depending on environmental conditions

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18
Q

List the microbes from less resistant to more resistant

A

Enveloped viruses
- very weak, soap destroys this

Most gram positive bacteria
- 2 layers

Fungi and fungal spores
- same sensitivity

Most gram negative bacteria
- 3 layers

Protozoan trophozoites

Protozoan cysts
- dormant stage = resistant

Staphylococcus and psuedomonas
- biofilm pioneer bacteria

Mycobacterium
- hydrophobic, waxy layer

Bacterial endospores
- most resistant, withstand everything

Prions

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19
Q

List the influencers/factors that determine the external factors of microbial control

A

Composition of the population
- endospores take long bc they’re so resistant

Concentration/dose of antimicrobial
- higher does and concentration needed for more resistant microbes (endospores)

Location
- what’s happening around microbe (table v hand)
- organic load: dirt, dust, feces, etc
- scenery (hospital v home)

Temperature
- hotter the better
- increase = kill
- decrease = inhibit growth

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20
Q

What’s the mode of action of antimicrobial processes

A

Inhibit some cell processes
- dna replication
- transcription
- translation
- metabolism

Alteration of membrane permeability
- things don’t go in and out like it should

Damage to the cell wall or inhibition of wall synthesis
- lysis

Damage to dna or proteins

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21
Q

Describe physical control methods

A

Outcomes: disinfection, sanitization, and sterilization

Usually only used on inanimate objects, liquids, or gases

Temperature, radiation, and filtration

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22
Q

Describe temperature as a physical control method

A

Hot
- moist heat
- pasteurization
- dry heat

Cold
- refrigeration
- freezing

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23
Q

Describe heat as a physical control method

A

Preferred process

Denatures nuclei acids, proteins, and lipids
- inhibiting cellular processes (=cell death)

Advantages
- quick, cheap, and no toxic residues

Disadvantages
- some heat processes do not remove endospores (disinfection)
- not everything can be heated to kill temperatures
- plastic will melt

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24
Q

List and describe examples of moist heat

A

Boiling
- temp and exposure time = 100C for 1-3 min
- aggressive booking full time
- achieves disinfection / sanitization

Steam
- autoclave
- 121C and 15 Ib pressure for 20 min
- sterilization

Canning
- high temp and pressure
- if not done well clostridium botulinum endospores will survive and cause food poisoning

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25
Q

Describe clostridium botulinum

A

Gram positive rod

Endospore former

Strict anaerobe
- forms gas

Neurotoxin

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26
Q

Describe pasteurization

A

Thermal process that is carried out in liquids (milk and juices) with the intention of reducing the presence of pathogens

Developed by Louis Pasteur
- prevent wine from going bad

Disinfection/sanitization

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27
Q

Describe dry heat

A

Less efficient than moist heat

For materials that cannot be exposed to water or moisture
- metals

Requires higher temperatures and exposure times
- ovens (16 hours at 121C)
- incineration (flaming loop)

Sterilization

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28
Q

Describe radiation as a physical control method

A

Damage DNA structure, preventing DNA replication and transcription

Ionizing: used in medical equipment and food preservation (penetrates)
- gamma
- X-rays
- sterilization
*most efficient for food but people are scared and expensive
- wont affect taste and texture

No ionizing: disinfection of surfaces, gases, and fluids
- UV light

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29
Q

Describe filtration as a physical control method

A

Mechanical control

Small pores of 0.2 um

Removal of microorganisms
- has no effect on microbes

It is used with materials that usually cannot go through other processes
- liquids and gases (ex: drugs intravenous)
- super expensive

Sterilization

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30
Q

What physical control methods is selectively toxic

A

None, all of these physical outcomes impact us

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31
Q

Describe chemical control

A

Use of chemical compounds for the control of microorganisms

Most used type of control

The effectiveness is affected by temp, exposure time, and amount of organic matter in the environment
- external factors play a huge role in effectiveness of these control methods

Concentration and age of the chemical also affect its effectiveness
- older = lose potency

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32
Q

Describe the activity levels of the chemical control methods as regarded by cdc

A

High level: effective against vegetative bacterial cells, mycobacteria, endospores, fungi, and viruses
- ethylene oxide, glutaraldehyde, formaldehyde
- sterilization

Intermediate level: effective against vegetative bacterial cells, mycobacteria, fungi, and viruses
- phenolics, halogens
- sterilization/disinfection

Low level: effective against vegetative bacterial cells, fungi, and maybe viruses (enveloped)
- alcohols, quaternary ammonium compounds
- disinfection

33
Q

Describe ethylene oxide

A

Gas

Sterilize
- high level

Used for medical equipment and products
- sutures, catheters, artificial valves, plastics
- things that cannot be autoclaved or heated

They damage proteins and dna

Negative: in high concentrations, they are explosive and poisonous

34
Q

Describe hydrogen peroxide

A

Liquid

Damages macromolecules by producing free radicals

Most effective against anaerobes
- no catalase or SODs to get rid of free radicals

Can sterilize inanimate objects in certain concentrations
- activity levels range depending on concentration

Works well with organic materials

Toxic to eyes and if ingested

35
Q

Describe halogens

A

Iodine or chlorine
- betaiodine, bleach

Gaseous or liquid

Effective against bacteria, fungi, many viruses, Protozoa, protozoal cysts, fungal spores

Some are low acting against endospores
- high concentration and long time exposure can get rid of endospores

Damages proteins

Chlorine can tolerate some organic material
- takes longer

36
Q

Describe alcohols 70-90%

A

Liquid

They damage proteins and plasma membrane

Bactericide, fungicide, and inactivated enveloped viruses

It does not eliminate spores

Positive: leaves no chemical residue

Negative: evaporates quickly leaving little contact time with microbes
- higher concentration, faster will evaporate

Low level

37
Q

Describe quaternary ammonium

A

Low activity

Also used for sanitation

Damages membranes

Low activity in the presence of organic matter

Clean first!

Detergents
- bc amphipathic

38
Q

Describe soaps

A

They only remove microbes

Antibacterial soaps are no more effective than regular soap and water for killing disease-causing germs, according to the CDC

Very low activity
- doesn’t kill, but removes

Non toxic

Inactivate enveloped virus

Detergent
- bc it’s amphipathic

39
Q

Describe and list the antimicrobial drugs

A

Antibiotics
- bacteria
Antifungal
- fungi
Antiparasitic
- protozoans
Antihelminthics
- parasitic worms
Antivirals
- virus

In industrialized countries viruses are more of a threat
- difficult to create and maintain antiviral drugs

Antibiotics keep most bacterial diseases under control
- more comfy dealing with bacterial infection bc we have more access to antibiotics

Prior to ww2 (1939-1945), most leading causes of death were bacterial infections

40
Q

Define antibiotics

A

Most of these come from another bacteria or fungi

Chemicals produced by a microbe to kill bacteria
- antagonist
- natural process in their habitat to compete

Microbes are better chemists than us

41
Q

Describe the antibiotic discovery

A

Alexander Fleming (1929)
- accidentally discovered
- fungal contamination on glass Petri dishes, noticed Sa wasn’t growing around fungus
- produced by Pencillum mold (fungi)
- decade after to understand why this occurs

Roadblock
- low production of penicillin by mold

42
Q

Describe the penicillin production over the years

A

1929 - discovery by Fleming

1938 - research on penicillin starts at Oxford
- searching why bacteria doesn’t grow around this mold

1940 - animal trials successful

1941 - scientists travel to Peoria IL to work on mass production

1942 - just enough for 10 patients

1943 - Mary Hunt finds cantaloupe with Gordon mold
- had to radiate, mutations produced enough penicillin

1944 - enough production for soldiers on D-Day
- survive infections and can continue fighting

1945 - WW2 Nobel , 646 billion units/year, novel prize
- Allie’s are credited to winning bc access to penicillin

Penicillin is a cidal antibiotic

43
Q

Describe the history of the antibiotic industry

A

From 1940s-1980, discovered and commercialized dozens of antibiotics

1980s- we’ve “conquered” infectious disease
- stop funding the research to find more antibiotics

1980s- more lucrative diseases apparent

44
Q

Define and describe selective toxicity

A

Specifically targets microbe, not host

Target key aspects of microbial life that are very different from those of eukaryotes
- 5 main categories

45
Q

Describe the 5 main categories that are targets of microbial life only

A

Peptidoglycan synthesis
- pencillin (cidal antibiotic)

Cell membrane
- outer membrane

Metabolic
- vitamin b12, made in bacteria but we get it from diet

DNA replication enzymes

RNA polymerase

Ribosomes

46
Q

What is better, an antibiotic that is static or cidal

A

Both are equally effective

Static allows our immune system to catch up

Body works with drug to get rid of bacteria

47
Q

Describe the toxicity and other side effects of antibiotics

A

May harm body tissues and organs
- liver damage and hearing loss

Disrupt the normal microbiota
- can’t tell between good and bad bacteria
- secondary infections: yeast, diarrhea
- opportunistic pathogens take over

Induce allergies and hypersensitivities
- immune system responding incorrectly

Contribute to antibiotic resistance

48
Q

What is better, narrow or broad spectrum

A

Narrow to maintain microbiota

Broad when patients don’t have time to wait

Narrow is ideal

49
Q

Define and describe antibiotic resistance

What is it

Why should we worry

Where does it come from

How is it spread

A

Antibiotics are no longer effective at controlling bacterial infection

Running out of effective antibiotics against infections and bacteria are not just resistant to one antibiotic (resistant to multiple)

Antibiotics do not cause antibiotic resistance

Spreads via conjugation, horizontal gene transfer, aka passing of genes

50
Q

Why does antibiotic resistance occurs

A

Changes in DNA
- mutations

Selection
- selecting for the mutants in the population
- these are already resistant so therefore they survive

Multiplication of resistant cells
- mutants will be most fit to grow and replicate

=Evolution

  • mutations and passing genes
51
Q

Why is antibiotic resistance a form of natural selection

A

Via directional selection
- one phenotype has the highest fitness, the bell curve shifts towards the more fit phenotype

52
Q

List the strategies for antibiotic resistance in microbes

A
  1. Keep antibiotics out of the cell
    - antibiotic doesn’t get into cytoplasm, won’t affect the cell
  2. Prevent antibiotics from binding the target
    - prevent enzyme from binding to antibiotic
  3. Dislodge an antibiotic already bound to it’s target
    - physically shoves
53
Q

Describe how bacteria keep antibiotics out of the cell

A
  1. Destroy the antibiotic via enzyme secretion (breaks it down)
    - enzyme specifically destroys penicillin (strategy for bacteria resistant to penicillin)
  2. Pump the antibiotic out of the cell
    - membrane pumps bail drugs out of cell faster than they can enter
    - not specific, can work for multiple antibiotics
    - work also against disinfectants
  3. Decrease membrane permeability (cell membrane, and/or outer membrane for G-)
    - modify transporter proteins so antibiotics don’t come in
    - not specific, works against multiple drugs
    - works against disinfectants
54
Q

Describe how bacteria prevent antibiotics from binding the target

A
  1. Modify the target so that it no longer binds the antibiotic
    - change binding site (mutations)
    - modify target enzyme, decorate with different chemical groups
  2. Make more copies of target
    - overproducing so some are inhibited but not all
    - not enough antibiotic in the cell, competition still exists
  3. Alternate pathway/enzyme
    - to get chemical run to continue
55
Q

Describe how bacteria dislodge antibiotics that are already bound to target

A

Newly discovered

Ribosome protection or rescue
- proteins that bind to ribosome and dislodge macro life antibiotics

Ribosomes read mRNA, add tRNA with amino acids and create the peptide binds that create the new proteins

Antibiotics bind in the spaces of the ribosome, blocks the reading/adding of amino acids and new peptide chain
- ribosome stalls, can’t continue

Protein shoves itself in the active site of the ribosome and pushes out the antibiotic

56
Q

What is the art of choosing antibacterial

A

Is the causal agent of disease known

Is the susceptibility to antibiotics or the causal agent known

Condition and history of the patient
- pre existing
- allergies
- affordability
- other conditions

57
Q

Describe microbial ecology

A

Study of interactions between organisms and the environment

Microbe interactions

Can find microbes in water, soil, and atmosphere

58
Q

Describe the relationship between microorganisms and the planet

A

Microbes are omnipresent
- everywhere

Microorganisms show great metabolic diversity
- have ability to generate atp from almost everything
- aerobic and anaerobic

Can switch nutritional types depending on environment and also do many processes that allow us to survive

59
Q

Describe tropic levels

A

Microbes found in all levels

Cycling of CHONPS
- all nutrients are linked

60
Q

Describe biochemical cycle

A

Sun of the microbial, physical, and chemical processes that drive the flow of elements
- everything needs to be cycled
- essential for health of planet

Microbial metabolism
- nutritional types
- electron donors
- carbon source

Relationship with oxygen
- electron acceptor

Many microbes working together
- good things
- bad things

61
Q

Describe nitrogen fixation

A

Breaking the three bonds

Prokaryotes can only do this.
- nitrogen is now available for all organisms

62
Q

Describe precipitation cycle

A

Microbes affect precipitation
- only in temperate climate

Pseudomonas syringae
- G-
- grows on plant leaves (plant pathogen
- ice nucleation protein in membrane
- water molecules to form ice in temp that doesn’t make ice
- uses this as a virulence factor to masserate the leaves via the dew

63
Q

Define symbiotic

A

Organisms live in close nutritional relationships; required by one or both members

Mutualism: both benefit

Commensalism: one benefit, other doesn’t buy isn’t harmed

Parasitism: one is harmed (aka pathogenesis)

PHYSICAL CONTACT

64
Q

Define nonsymbiotic

A

Organisms are free living; relationships not required for survival

Synergism: members cooperate and share nutrients
- waste product is nutrients for others
- biogeochemical cycle works bc of this

Antagonism: some members are inhibited or destroyed by others
- produce something that harms the other

NO PHYSICAL CONTACT

65
Q

Describe the human microbiota/microbiome

A

All the microbes found in the human body

Estimates of microbiota numbers vary (just bacteria)
- same number of bacteria as human cells (10^14)
- 6 pounds of microbes, brain weighs 3 pounds

66
Q

Describe “normal” microbiota

A

Different parts of our body has different types of bacteria

Every environment is doing to select for a different group of microbes
- some microbes will be found in multiple places, others only 1
- due to the environment (change in temp, pH, oxygen, etc)

67
Q

When is the microbiota acquired

A

Before birth (a little)

Majority is acquired during birth
- natural (maternal vaginal microbiota)
- cesarean section (maternal skin microbiota)

Microbiota changes through human development

Completion of the microbiota also depends on the diet
- fiber is key for healthy microbiota

At toddlerhood, all have the same microbiota regardless of delivery form

68
Q

What are factors that affect microbiota

A

Balance:
Birth mode, feeding type, siblings, daycare, season

Imbalance: vaccinations, infection, antibiotics, and smoking

Genetics is for both

69
Q

How do you acquire an abundant and diverse microbiota

A

Fiber

A good guy health is a microbiota that is diverse and abundant

70
Q

What are the benefits of a microbiome

A

Digesting food (plant fiber)
- we don’t have the enzymes, they produce short chain fatty acids that our intestine cells can digest

Vitamins (b and k)

Helps develop intestines

Help develop and enabling function of the immune system

Interfering with colonization by pathogens by:
- competing for attachment sites (all chairs are filled)
- competing for food sources
- synthesizing antimicrobial compounds

71
Q

Describe the direct and indirect mechanism that the microbiota does to protect us from pathogens

A

Direct: Interactions between gut microbes
- nutrient consumption
- antagonism

Indirect: induction of host cell response
- antimicrobial peptides
- host immune cell response
* microbiota alerts our immune system

72
Q

What are the risks of a microbiome

A

Microbiota may escape and cause infection and disease

Opportunistic pathogens among the microbiota cause disease in immunocompromised hosts

Compounded by acquired antibiotic resistance

73
Q

How does microbiota communicate with host

A

Microbial metabolites in blood and urine affect host gene expression

Human neurotransmitters and hormones change bacterial gene expression

  1. Host products affecting the microbiota (hormones)
  2. Cross-species effects / quorum sensing
  3. Microbiota products affecting the host (butyrate, índole, others)

They talk via chemical communication (bacteria and host cells)

74
Q

Describe the microbiome-brain gut axis

A

But microbiota produces compounds that have nueroyrsnsmiyyer activity

Microbiota can affect behavior

Correlation between microbiota and anxiety moods, autism, Parkinson’s

  • vagus nerve goes from gut to brain, these signaling molecules that are produced by the gut bacteria travel through the vagus nerve and that’s how our behavior can become affected by microbes
75
Q

How do we change the microbiota

A

Diverse and abundant is good

Antibiotic use (less)

Obsession with hygiene (less)

Diet (depending, fiber will increase)

Supplements (not FDA regulated)
- prebiotic (fiber, help microbiota that is already present)
- probiotic (actual microbes, higher number)
- postbiotics (products the microbiota makes: short chain fatty acids that microbes produce)

Microbiota transplants
- fecal transplants to improve gut health, specifically combat against c diff (anaerobic endospores former that is caused by prolong antibiotic use)
- fecal donor is from someone that lives with patient or relative

76
Q

What is microbiome dysbiosis

A

Microbiome is out of wack
- less diverse and less abundant
- prolonged antibiotic usage

A lot of diseases are correlated to a change in the microbiome
- obesity
- rheumatoid arthritis
- diabetes
- inflammatory bowel disease
- non alcoholic fatty liver disease
- carcinogénesis
- pulmonary disease and asthma
- atherosclerosis

77
Q

Describe the relationship between obesity and microbiota

A

Microbiota of obese mice were transplanted into germ free mice

These mice became obese despite consuming the same diet

Bacteria eats fiber and produces short chain fatty acid and hydrogen gas (process of fermentation) -> hydrogen gas is a feedback inhibitor, tells bacteria went to stop producing short chain fatty acids
- methanogens will use co2 and hydrogen gas, if we consume hydrogen gas, we are removing this inhibition and allowing for more short chain fatty acid to be produced (calories)

78
Q

What is the hygiene hypothesis

A

Lack of exposure to microbes during childhood
- increases susceptibility to allergies and asthma in adulthood
- delayed or incorrect development of the immune system

People in developing countries have a larger and more diverse microbiota and lesser incidence of autoimmune diseases (vice versa)

79
Q

List the altering of composition of microbiota in: clean water, cesarean deliveries, use of preterm antibiotics, reduced breast-feeding, smaller family size, widespread antibiotic use, increases bathing and use of antibacterial soap, use of mercury amalgam dental fillings

A

Reduced fecal transmission of bacteria

Reduced vaginal transmission

Reduced vaginal transmission

Reduced cutaneous transmission and altered immunological environment

Reduced early life transmission

Accelerates change of microbiome composition

Accelerates change of skin microbiome composition

Accelerates change of oral cavity microbiome composition

Microbio (4 decks)

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