Chapter 11: Physical and Chemical Control of Microbes

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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
2

• 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
3

• 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.)

nosocomial
weakened
pathogenic
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
4

• 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!)

microbe
contamination
environmental
infection
endospores
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
dirt
saliva
blood
feces
5

• D. Potential risk of infection
• 1. _______ items come into direct contact with
  body tissues.

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

Heat
denaturing
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) 63C/30 minutes (2). HTST (High
Temperature Short Term) 72C/15 seconds

Autoclave
c. __________ (steam under pressure) (1).
15-20 psi/15-20 minutes/121C (2). ________
equipment, media, etc. (3). used in canning
procedures to destroy Clostridium botulinum
__________!
Sterilizes
endospores
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2. ___ heat sterilizes. a. Hot air ovens
(160-170C/2-3 hours) used when ________ is
undesirable. b. ____________ (burning)
(1). _________/___________used to destroy
disposable items, soiled dressings, tissue
specimens etc. _at_ 800C to 6500C c. The
hottest part of a Bunsen burner flame reaches
1,870C for ______ during lab.
Dry
moisture
Incineration
furnaces
incinerators
flaming
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• B. Radiation (waves having energy but no mass)
  causes lethal changes in DNA, denatures proteins,
  but doesnt 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.

ultraviolet
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

• 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)

membrane
DNA
proteins
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

• 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
• lt 1 means _____ efficient than phenol
• gt 1 means _____ efficient than phenol

time
organism
identical
concentration
less
time
greater
less
more
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• 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)

Toxicity
material
Residue
Cost
Storage
Environmental
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• 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)

Chemical
acids
nitrates
nitrites
refrigerator
4
freezer
-20
osmotic
sugar
salt
Desiccation
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E. ____________ (freeze-drying) 1. materials
_______ frozen at temperatures well below 0C 2.
vacuum while frozen to remove ________
(lightweight) 3. biological cultures,
medications, foods (expensive)
Lyophilization
rapidly
moisture
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Chap 12 Elements of 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

Chemotherapy
Chemotherapeutic
Antimicrobial
Natural
Synthetic
Semi-synthetic
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• B. Modes of action
• 1. interfere with microbes 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
19
(No Transcript)
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Folic acid
PABA
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B. Modes of action 1. interfere with
microbes 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
22
Glycan backbone
23
B. Modes of action 1. interfere with
microbes 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
24
amphipathic
25
B. Modes of action 1. interfere with
microbes 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
26
(No Transcript)
27
B. Modes of action 1. interfere with
microbes 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
28
C. Criteria that determine the effectiveness of
antimicrobial agents 1. ________ toxicity
destroys or inhibits microbe without affecting
host cells
Selective
Spectrum

• 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)

Broad
secondary
Narrow
Soluble
Stable
oral
absorbed
Half-life
frequency
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allergenic

• 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 ____________.

mutagenic
toxic
normal flora
Allergic
resistant
enzymes
mutations
plasmids
Conjugation
Transduction
Transformation
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• 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

Discriminate
identification
prescription
intervals
time
Synergistic
disk-plate diffusion
lawn
antibiotics
Incubate
31

• 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!

inhibits
Zone of inhibition
Satellite
resistant
Overlapping antibiotics (with synergistic
effects) may be needed if satellite colonies
appear.
Location of satellite colonies if present