Control of Microbial Population Flashcards

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1
Q

What is Ebers Papyrus

A

ancient document showing that people of ancient times were interested in how to treat diseases

document had tx for everything under the sun

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2
Q

Who is Paul Ehrlich

A

popularized the concept of magic bullet and also invented first tx for syphilis thereby initiating and naming the concept of chemotherapy

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3
Q

Who is Alexander Fleming

A

rediscovered penicillin

left petri dishes over night and noticed where fungi was growing, there was no bacteria

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4
Q

Who is Gerhard Domagk

A

red azo dyes –> compound will kill bacteria

prontonsil –> first antibiotic

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5
Q

what are the two methods of microbial control

A

physical and chemical

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6
Q

difference between physical and chemical methods for microbial control

A

physical: high temp (moist heat, pasteurization, dry heat), low temp, radiation, filtration, ethylene oxide gas
chemical: food preservatives, disinfectants, antiseptics, antibiotics, antifungals, antivirals

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7
Q

what roadmap does one use to go about deciding how to control microbes

A

what is it?
where is it?
what do you need to achieve?

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8
Q

Given streptococcus pyogenes as an example, use the roadmap to decide how you would go about controlling it

A

what is it? - streptococcus pyogenes
where is it? - living tissue (soft tissues of arms)
what do you need to achieve? - inhibition of growth

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9
Q

what microbe is most resistant to disinfectant and antiseptic agents

A

bacterial spores

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10
Q

what agent is successful at killing all the microbes which includes bacteria, virus, fungus, bacterial endospores, mycobacteria

A

formaldehyde and glutaraldehyde

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11
Q

difference between disinfectants and antiseptics

A

disinfectants tends to be used on hard surfaces while antiseptics can be used on living tissue like our skin and such

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12
Q

what agent can be used as both a disinfectant and an antiseptic

A

iodophors and alcohol

hence these two can be used on hard surfaces and living tissue

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13
Q

what microorganism is resistant to a lot of antiseptics and disinfectants

A

bacterial spores

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14
Q

what does it mean that bacterial spores have inherent resistance

A

endospore formation of a biofilm or a structural component of cell such as a waxy coating or outer membrane is where these microorganisms get their resistance from (AKA their resistance is not acquire rather it is innate)

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15
Q

what is meant by acquired resistance

A

microorganism building a resistance to an antiseptic or disinfectant agent due to multiple exposure (AKA it is not innate)

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16
Q

most resistant microorganisms

A

prions –> endospores –> mycobacteria

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17
Q

most susceptible microorganisms

A

enveloped virus –> gram pos bacteria —>large non enveloped viruses

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18
Q

NOT SURE HOW IMPO THIS IS but list the organisms from most resistant to most susceptible

A

prion –> endospores –> mycobacteria –> small non enveloped viruses –> fungal spores –> gram neg viruses –> vegetative fungi –> large non enveloped viruses –> gram pos bacteria –> enveloped viruses

PEMS-FGV-LGE

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19
Q

what does the number of microorganisms influence

A

tx type, duration, conc etc

20
Q

what is the difference in time of inactivation in a bacteria vs. a bacterial endospore

A

it takes longer to kill those with an endospore and might take a higher conc of tx and even possibly a diff tx

21
Q

give an example of a gram neg and a gram pos bacteria

A

gram neg - E. coli

gram pos - S. aureus

22
Q

how does the MIC (minimum inhibitory concentration) differ in E. coli vs. S. aureus?

A

since E. coli is a gram neg bacteria, it takes higher MIC to inhibit its growth

23
Q

what are some goals to achieve when it comes to microbes

A
  • reducing microbial numbers to sanitary/acceptable levels
  • slow down or inhibit microbial growth
  • kill microorganism
  • prevention vs. treatment
24
Q

what is used to reduce microbial numbers to sanitary/acceptable levels

A

disinfectants

25
Q

what is the process called when killing microorganisms

A

sterilization

26
Q

what is difference in prevention vs. treatment

A

in prevention, antiseptics and disinfectants are used

in tx, therapeutic antibiotics are used

27
Q

most effective liquid sterilant available

A

peracetic acid

28
Q

why is peracetic acid considered so effective

A

kills endospores and viruses in 30 mins
kills bacteria and fungi in less than 5 mins
kills most microorganisms

29
Q

what are some advantages of peracetic acid

A

no toxic residue

minimally affected by organic matter

30
Q

what is peracetic acid actually used for

A

high level disinfection for eg heat or steam sensitive instruments for invasive procedures

31
Q

what is the difference between an addition of a static and cidal compound during the log phase

A

static - keeps the microbes constant and they cannot replicate anymore

cidal - actually kills the microorganisms

32
Q

difference in bacteriostatic and bacteriocidal in term of onset, requiring functional immune system, used in immunocompromised pt, used in life threatening situations respectively

A

bacteriostatic - slower, Yes, not advised, not advised

bacteriocidal - faster, no, yes, yes

33
Q

why do bacteriostatic compounds require a functioning immune system

A

bacteriostatic compounds keep microbes constant so they can’t replicate so they need the immune system to step in and finish the job

34
Q

what is more than 80% of the antibiotics we make used for?

A

to feed animals to treat food and not for actual tx of disease

35
Q

what differentiates between therapeutic and preventive antimicrobials

A

the specificity of the target – therapeutic is more specific –> they target structures and physiological function

36
Q

can some compounds be both bacteriostatic and bacteriocidal

A

yes they can – they can be bacteriostatic at some concentrations and then bacteriocidal at another concentration

37
Q

what can happen with the addition of two compounds aimed at killing microbes

A
  • they can be indifferent (no change)
  • can be synergistic: work cooperatively together to kill microbes a lot quicker
  • can be antagonistic: can antagonize each other hence getting worse results
38
Q

what is selective toxicity

A

compounds with minimal or no effect on host cells but maximum effect against the infecting microorganism

39
Q

what are some examples of ideal targets unique to infecting microorganisms

A
peptidoglycan (antibacterial)
ergosterol (antifungal)
reverse transcriptase (antivirals)
40
Q

what are some alternative targets for infecting microorganisms

A

targets that are suitably different from that of the host cell equivalent

41
Q

which microbial groups are harder to achieve with?

A

eukaryotes because we as humans are also eukaryotes so they are lots of similarities so must be really specific/unique with the target

42
Q

why do some compounds only have an application in prevention and what is an example?

A

an example would be disinfectants – they only have a target in prevention because their general mechanism of action means they will be harmful to living tissue

43
Q

what is the importance of penicillin generations

A

they are some chemical changes between each that help improve half life and other pharmacological aspects

44
Q

what are natural sources of antibiotics

A

actinomycetes
filamentous fungi
bacteria especially streptomyces

45
Q

where is penicillin originally from

A

penicillium chrysogenum though it is now produced semi synthetically

46
Q

other sources of antibiotics

A

end products (secondary metabolites) of fermentation pathway
synthetic: quinolones (by product of antimalarial drugs)
analogs of nalidixic acid, quinolone, or derived ring (fluoroquinolone)