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Chapter 11: Physical and Chemical Control of Microbes. aseptic. Lister.

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Chapter 11: Physical and Chemical Control of Microbes

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Chapter 11 physical and chemical control of microbes l.jpg

Chapter 11: Physical and Chemical Control of Microbes

aseptic

Lister

  • Joseph ______ started _________ techniques with medical applications. By using carbolic acid (_______) -soaked rags and instruments during and after surgery, gangrene and other infections following surgery greatly diminished.

  • II. Terminology and Methods of Control

  • A. _____________means COMPLETE destruction of viruses and

  • microbes (including endospores) so that even if they are placed

  • in a new growth medium, they will not revive or reproduce.

  • B. __________means to reduce the number of pathogens (including viruses) until they are not a hazard, usually involving the use of antimicrobial chemicals.

  • C. _______________ refers to removing toxins.

  • D. ____________ refers to a substantially

  • reduced microbial population that meets

  • accepted health standards.

  • A clean appearance is expected!

phenol

Sterilization

Disinfection

Decontamination

Sanitization


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E. Different situations warrant different levels of microbial control.

1. daily life

Simple ____________ with plain soap and water

is considered to be the single most important step in

preventing the spread of many infectious diseases!

handwashing


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nosocomial

weakened

pathogenic

2. hospitals

Danger of ___________ (hospital acquired) infections because of:

a. _________ condition of hospitalized patients

b. higher concentration of sick people with ____________ microbes (*many resistant forms!!)

c. _______ procedures (such as)

d. many health care workers are ______

e. lack of _______ care (handwashing

between patients, using gloves, etc.)

invasive

carriers

aseptic

3. microbiology/research/hospital laboratories

must use ________ techniques

a. Work surfaces should be ______.

b. All media and instruments must be ______.

c. Used ________ must be properly disposed of.

aseptic

clean

sterile

cultures


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microbe

contamination

environmental

infection

endospores

III. Selection of an antimicrobial procedure depends on many factors such as the type of _______, the extent of ____________, ____________ conditions, and potential risk of _________.

A. types of resistant microbes

1. Bacillus and Clostridium can make ___________.

2. Mycobacterium has ______ cell walls.

3. ____________ is capable of metabolizing unusual

substances for food. (Like disinfectants!)

waxy

Pseudomonas

B. the extent of contamination (size of the microbial population)

1. ‘Industry standard’ requires that ____% of the population is killed with every __ minutes of exposure to the treatment

a. 100 microbes  10 microbes  1 microbe in __ minutes

b. 1010 microbes        would take ___ minutes

SO, ________/_________ first helps reduce the population before disinfection or sterilization.

C. environmental conditions

1. _____________ ( heat chemical action)

2. _____

3. ____, _______, _______, ______ can all block chemical action

90

2

4

20

washing

scrubbing

temperature

pH

saliva

dirt

blood

feces


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Critical

D. Potential risk of infection

1. _______ items come into direct contact with body tissues.

Semicritical

2. ____________ items come into contact with mucous membranes, but do not penetrate body tissues.


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Noncritical

3. ____________ items only touch keratinized skin surfaces.

IV. Methods of Physical Control

A. ______ works by_________ cell proteins /enzymes. It is the most common control method because it is fast, reliable, inexpensive & nontoxic.

1. ______ heat

a. _______ 100°C/10 minutes (kills most microbes & inactivates most viruses, but does not destroy __________).

denaturing

Heat

Moist

Boiling

endospores


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Pasteurization

b. ____________: a brief heat treatment followed by rapid cooling.

(Kills pathogens and reduces the number of spoilage organisms in

milk, juices, wine, beer: Does not sterilize!)

(1). LTLT (Low Temperature Long Term) 63°C/30 minutes

*(2). HTST (High Temperature Short Term) 72°C/15 seconds

Autoclave

c. __________ (steam under pressure)

(1). 15-20 psi/15-20 minutes/121°C

(2). ________ equipment, media, etc.

(3). used in canning procedures to destroy

Clostridiumbotulinum __________!

Sterilizes

endospores


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Microbiology is Fun!

2. ___ heat sterilizes.

a. Hot air ovens (160-170°C/2-3 hours) used when ________ is undesirable.

b. ____________ (burning)

(1). _________/___________used to destroy disposable items,

soiled dressings, tissue specimens etc. @ 800°C to 6500°C

c. The hottest part of a Bunsen burner flame reaches 1,870°C for ______ during lab.

Dry

moisture

Incineration

furnaces

incinerators

flaming


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ultraviolet

B. Radiation (waves having energy but no mass) causes lethal changes in DNA, denatures proteins, but doesn’t reliably destroy endospores)!

1. Nonionizing rays = ________

radiation

a. can be used to reduce the number

of organisms in air and on clean

surfaces

b. of limited use, cannot penetrate

materials like cloth, glass, paper

2. Ionizing rays = ________ or _____________

a. can be used to __________ items that are

heat or chemical sensitive, such as plastics

b. more effective, penetrates liquids and most

solids (used to treat Washington DC mail)

c. In the US, radiation is approved to treat

pork to prevent ___________, to treat beef

for ________ contamination and used to

treat chicken for _________ contamination.

X-rays

Gamma rays

sterilize

trichinosis

E. coli

Salmonella


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3. microwaves

a. do not affect microbes directly, but may kill by _____ they

generate

b. drawback is that microwave heating is ________

heat

uneven

C. Filtration (may be used for air, some heat sensitive materials such

as serum, vaccines, drugs, IV fluidsbeer/wine)

1. _____ ________ ________ ____ (HEPA) filters remove

airborne contaminants; used in operating rooma, for people with

allergies, etc.

2. In fluid filtration, _______ are separated from ________ by passing through _______ with extremely fine pores

a. Mechanical force or vacuum suction helps fluid through the filter

b. does not sterilize unless pore size is small enough to trap everything (smaller pores,  cost)

High-Efficiency Particulate Air

liquids

solids

filters


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Chemical

membrane

DNA

proteins

V. Methods of ________ Control (* for heat sensitive items, large surfaces)

Destructive actions include injury to the cell _________,

denaturation of cell ________, inhibiting replication of _____.

A. Disinfectants Vs Antiseptics

1. _____________ are chemicals used on inanimate objects.

a. ___________ are chemicals that KILL/DESTROY germs.

(examples: fungicides, bactericides, viricides)

b. __________ refers to chemicals that do not kill, but

prevent the growth of microbes .

(examples: bacteriostatic, fungistatic)

2. __________ are disinfectants nontoxic enough to be used on

skin.

B. Germicides are grouped according to their _______ (strength)

1. __________ destroy everything, including endospores

(for sterilizing scalpels, respiratory therapy equipment,

proctoscopes, plastic Petri dishes, endoscopes)

(ethylene oxide gas, hydrogen peroxide)

Disinfectants

Germicides

Germistatic

Antiseptics

potency

Sterilants


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High

2. ____ level disinfectants (do not reliably destroy endospores)

(used for GI endoscopes) (iodine, phenol, chlorhexidine, heavy

metals such as silver nitrate)

3. ___________ level disinfectants (will kill Mycobacterium, but do

not destroy all viruses or endospores, even with prolonged

exposure) (used for stethoscopes, electrodes, thermometers)

(alcohols: ethyl alcohol, isopropyl)

4. _____ level disinfectants (will not kill Mycobacterium)

(soaps, detergents)

Intermediate

Low


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Phenol coefficient

time

identical

organism

concentration

less

C. ______ _________ (5% Phenol is the standard against which

chemical agents are tested and compared)

1. Each chemical is compared for the same length of _____

on the same _________ under ________ conditions

2. IF the chemical being tested requires a greater ____________

or a longer ______ than phenol, its efficiency is _____ than

phenol.

IF the chemical being tested requires a lower concentration or a shorter time than phenol, its efficiency is _______ than

phenol.

3. Ratio of: tested chemical activity

phenol activity

< 1 means _____ efficient than phenol

> 1 means _____ efficient than phenol

time

greater

less

more


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Toxicity

material

D. Selecting the Appropriate germicidal chemical

1. ________ (the benefit of disinfecting or sterilizing an item or

surface must be weighed against the risks associated with the use

of that chemical) (hospital Vs home/office)

2. compatibility with the ________ being treated (metal, rubber,

glass, plastic)

3. ________ may necessitate rinsing

4. ______ and availability (bleach)

5. _________ and stability (concentrates require less space and

store for long periods, but when diluted/mixed, often have limited

shelf life)

6. _____________risk (disposal procedures needed)

Residue

Cost

Storage

Environmental


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Chemical

acids

nitrates

VI. Methods used for Preservation (delaying spoilage) of Perishable

Products

A. ________ preservatives (both nonfood and food)

1. organic ______ lower pH (inactivates enzymes, inhibits

growth, but does not always destroy microbes)

2. ________ and _______ inhibit germination of Clostridium

botulinum endospores!

B. Low Temperatures

1. _____________

a. 0-10° C (___° C average)

b. retards but does not prevent growth

2. ________

a. ___° C

b. prevents growth but does not kill all organisms

C. Increased _______ pressure by adding _____ or ______; causes water to leave the cell, killing it.

D. ___________ (dehydration) of the material (natural [sun] or

artificial)

nitrites

refrigerator

4

freezer

-20

osmotic

sugar

salt

Desiccation


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E. ____________ (freeze-drying)

1. materials _______ frozen at temperatures well below 0°C

2. vacuum while frozen to remove ________ (lightweight)

3. biological cultures, medications, foods (expensive)

Lyophilization

rapidly

moisture


Chap 12 elements of chemotherapy l.jpg

Chap 12: Elements of Chemotherapy

Chemotherapy

I. Terminology

A. ____________ = use of chemical agents to treat disease

B. _________________ agent (CTA) = chemical agent used for treatment of disease (even cancer)

C. _____________ agent (AMA) = chemical agent used to treat diseases caused by microbes

II. Antimicrobial Agents

A. Types of antimicrobial agents

1. ________ agents = metabolic products produced by certain groups of fungi and fungal-like bacteria that are antibacterial in action

2. __________ agents = produced in the laboratory

3. _______________ agents = derivatives of natural agents

altered in the laboratory by adding chemical groups to

improve effectiveness

Chemotherapeutic

Antimicrobial

Natural

Synthetic

Semi-synthetic


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enzymes

competitive

B. Modes of action

1. interfere with microbe’s chemosynthesis by inhibiting ________

2. Disruption/interference with

a. of an essential metabolite by _________ inhibition

(Sulfa drugs mimic PABA, blocking folic acid synthesis) (p. 77)

b. by weakening/disrupting the bacterial cell ______

(Penicillin inhibits the enzyme that builds the amino acid cross-

linkages of peptidoglycan) (p. 78)

c. by damaging the cell ___________ (Polymixin cleaves the

layers of the membrane like a knife) (p. 78)

d. by inhibiting ________________ at 70s ribosomes (p. 79) (Erythromycin inhibits translocase, freezing the ribosome on

the mRNA.)

(Tetracycline blocks tRNA attachment to mRNA) (Chloramphenicol inhibits transferase, preventing peptide

bond formation between amino acids.)

(Streptomycin causes a misreading of mRNA.)

e. by inhibiting nucleic acid (______ and/or ____) synthesis (Antiviral: AZT inhibits reverse transcriptase.)

(Antibacterial: rifampin inhibits RNA polymerase.)

(Antifungal: griseofulvin inhibits RNA polymerase.)


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Folic acid

PABA


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B. Modes of action

1. interfere with microbe’s chemosynthesis by inhibiting ________

2. Disruption/interference with

a. of an essential metabolite by _________ inhibition

(Sulfa drugs mimic PABA, blocking folic acid synthesis) (p. 77)

b. by weakening/disrupting the bacterial cell ______

(Penicillin inhibits the enzyme that builds the amino acid cross-

linkages of peptidoglycan) (p. 78)

c. by damaging the cell ___________ (Polymixin cleaves the

layers of the membrane like a knife) (p. 78)

d. by inhibiting ________________ at 70s ribosomes (p. 79) (Erythromycin inhibits translocase, freezing the ribosome on

the mRNA.)

(Tetracycline blocks tRNA attachment to mRNA) (Chloramphenicol inhibits transferase, preventing peptide

bond formation between amino acids.)

(Streptomycin causes a misreading of mRNA.)

e. by inhibiting nucleic acid (______ and/or ____) synthesis (Antiviral: AZT inhibits reverse transcriptase.)

(Antibacterial: rifampin inhibits RNA polymerase.)

(Antifungal: griseofulvin inhibits RNA polymerase.)

enzymes

competitive

wall


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Glycan “backbone”


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B. Modes of action

1. interfere with microbe’s chemosynthesis by inhibiting ________

2. Disruption/interference with

a. of an essential metabolite by _________ inhibition

(Sulfa drugs mimic PABA, blocking folic acid synthesis) (p. 77)

b. by weakening/disrupting the bacterial cell ______

(Penicillin inhibits the enzyme that builds the amino acid cross-

linkages of peptidoglycan) (p. 78)

c. by damaging the cell ___________ (Polymixin cleaves the

layers of the membrane like a knife) (p. 78)

d. by inhibiting ________________ at 70s ribosomes (p. 79) (Erythromycin inhibits translocase, freezing the ribosome on

the mRNA.)

(Tetracycline blocks tRNA attachment to mRNA) (Chloramphenicol inhibits transferase, preventing peptide

bond formation between amino acids.)

(Streptomycin causes a misreading of mRNA.)

e. by inhibiting nucleic acid (______ and/or ____) synthesis (Antiviral: AZT inhibits reverse transcriptase.)

(Antibacterial: rifampin inhibits RNA polymerase.)

(Antifungal: griseofulvin inhibits RNA polymerase.)

enzymes

competitive

wall

membrane


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hydrophilic

hydrophobic

amphipathic


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B. Modes of action

1. interfere with microbe’s chemosynthesis by inhibiting ________

2. Disruption/interference with

a. of an essential metabolite by _________ inhibition

(Sulfa drugs mimic PABA, blocking folic acid synthesis) (p. 77)

b. by weakening/disrupting the bacterial cell ______

(Penicillin inhibits the enzyme that builds the amino acid cross-

linkages of peptidoglycan) (p. 78)

c. by damaging the cell ___________ (Polymixin cleaves the

layers of the membrane like a knife) (p. 78)

d. by inhibiting ________________ at 70s ribosomes (p. 79) (Erythromycin inhibits translocase, freezing the ribosome on

the mRNA.)

(Tetracycline blocks tRNA attachment to mRNA) (Chloramphenicol inhibits transferase, preventing peptide

bond formation between amino acids.)

(Streptomycin causes a misreading of mRNA.)

e. by inhibiting nucleic acid (______ and/or ____) synthesis (Antiviral: AZT inhibits reverse transcriptase.)

(Antibacterial: rifampin inhibits RNA polymerase.)

(Antifungal: griseofulvin inhibits RNA polymerase.)

enzymes

competitive

wall

membrane

protein synthesis


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B. Modes of action

1. interfere with microbe’s chemosynthesis by inhibiting ________

2. Disruption/interference with

a. of an essential metabolite by _________ inhibition

(Sulfa drugs mimic PABA, blocking folic acid synthesis) (p. 77)

b. by weakening/disrupting the bacterial cell ______

(Penicillin inhibits the enzyme that builds the amino acid cross-

linkages of peptidoglycan) (p. 78)

c. by damaging the cell ___________ (Polymixin cleaves the

layers of the membrane like a knife) (p. 78)

d. by inhibiting ________________ at 70s ribosomes (p. 79) (Erythromycin inhibits translocase, freezing the ribosome on

the mRNA.)

(Tetracycline blocks tRNA attachment to mRNA) (Chloramphenicol inhibits transferase, preventing peptide

bond formation between amino acids.)

(Streptomycin causes a misreading of mRNA.)

e. by inhibiting nucleic acid (______ and/or ____) synthesis (Antiviral: AZT inhibits reverse transcriptase.)

(Antibacterial: rifampin inhibits RNA polymerase.)

(Antifungal: griseofulvin inhibits RNA polymerase.)

enzymes

competitive

wall

membrane

protein synthesis

RNA

DNA


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C. Criteria that determine the effectiveness of antimicrobial agents

1. ________ toxicity = destroys or inhibits microbe without

affecting host cells

Selective

Spectrum

Broad

2. __________ of activity = range of microbes inhibited or killed

a. ______spectrum usually effective against Gram+ and Gram-

bacteria

(1). useful when no time to figure out exactly which microbe is

causing disease

(2). disadvantage is that it disrupts normal flora too (resulting in

__________ infections caused by opportunists).

b. _______spectrum requires identification of the pathogen

3. Tissue distribution, metabolism & excretion

a. ______ in body fluids (to be distributed in the blood)

b. _______ in body fluids (so it is not broken down easily)

assuring constant and effective levels in the body (pH of

stomach may limit ______ administration unless coated)

c. must be _________ by body tissues affected

d. _________ refers to the elimination rate of a drug

(this dictates the ___________ of dosage needed)

secondary

Narrow

Soluble

Stable

oral

absorbed

Half-life

frequency


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allergenic

mutagenic

toxic

4. should be non __________ and not cause adverse reactions

5. should be non __________ to reduce development of resistant

strains

D. Disadvantages of antimicrobial therapy

1. ______ effects on normal tissues (especially liver &/or kidneys)

2. disturb ____________

3. ________ reactions

4. development of __________ strains of bacteria, usually by

producing _________ that destroy AMA (such as penicillinase)

a. _________ occur naturally

b. resistance genes on _________ that can be spread from

bacterial cells to other bacterial cells by ____________,

______________, or ____________.

normal flora

Allergic

resistant

enzymes

mutations

plasmids

Conjugation

Transduction

Transformation


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Discriminate

identification

prescription

E. Avoid disadvantages by

1. __________ (careful) use of AMA

a. Dr: proper ____________ of disease

microbe & proper __________ of AMA

b. patient: maintain proper levels by

(1). taking medication at prescribed

_________

(2). taking medication for prescribed

length of _____

2. _________ effect of combination of 2-more AMA when resistance is likely to develop

F. AMA testing = _________________

method (p. 66)

1. procedure

a. Inoculate a solid ______ of

bacteria on agar

b. Place paper disks saturated with

various _________ on the surface

c. ________ 24 hours and then observe

intervals

time

Synergistic

disk-plate diffusion

lawn

antibiotics

Incubate


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inhibits

Zone of inhibition

2. The principle behind this is that during incubation, the antibiotic diffuses into the agar and, if effective, ________ growth of the bacteria in its presence.

3. observations

a. _________________ (no growth around the disk means the

AMA is effective)

b. _________ colonies are isolated colonies in the zone of

inhibition

They represent ________ cells from the original population!

Satellite

resistant

Overlapping antibiotics (with synergistic effects) may be needed if satellite colonies appear.

Location of satellite colonies if present


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