2 - Control of Microbrial Growth (with LE Q's) Flashcards
1
Q
microorganisms capable of causing disease (pathogens or potential pathogens)
A
infectious
2
Q
unwanted microbes i.e. vegetative cells, endospores, protozoan cysts, fungal hyphae, viruses, etc
A
contaminant
3
Q
hospital acquired infection
A
nosocomial infection
4
Q
clean safe food prep, cleaning dirt/dust; personal hygien
A
normal household conditions
5
Q
improved personal hygiene (handwashing); routine use of chemical disinfectants
A
general medical conditions
6
Q
assume patients are infectious; use PPE; wash hands etc
A
Standard precautions
7
Q
BSL-1
A
agents NO known potential for infection
8
Q
BSL-2
A
clinical samples, including HIV and several more unusualy pathogens (not highly transmissible by respiratory route); PPE, lab access, special handling
9
Q
BSL-3
A
more unusual or HIGHLY transmissible i.e. Mycobacterium tuberculossi, Brucella spp., infrequently encountered viruses, mold stages of fungi (highly transmissible respiratory. Precautions include Level 2 precautions HEPA filter mask, special lab design for control of air movement
10
Q
BSL-4
A
agents highly infectious exotic microbes and toxins for which there is no vaccine or effective treatment requiring MAX containment
11
Q
free of all microorganisms and their spores i.e. microbes have been destroyed or removed
A
sterile
12
Q
use of physical procedures or chemical agents to destroy all microbial forms, including bacterial spores (kill or remove the microbes)
A
sterilization
13
Q
procedures or chemical agents to destroy, inhibit, neutralize, or remove AT LEAST most of infect org
A
disinfect / decontaminate
14
Q
agent or method (usually chemical) used to carry out disinfection; normally used on inanimate objects (levels of high, intermediate, low effects)
A
disinfectant agents
15
Q
chemical agents on skin to eliminate or inhibit microorganisms (mild disinfectant)
A
antiseptic
16
Q
-cide, -cidal
A
kills microbe e.g. bacteria, fungi, viruses (maybe not spores)
17
Q
destroys spores & vegetative cells
A
sporicidal
18
Q
-stat, -static
A
inhibiting growth (prevent) or multiplication of bacteria, but not killing
19
Q
applying mild heat to kill, or reduce microbes that spoil food & beverage
A
pasteurization
20
Q
free of contaminating or infectious microorg
A
aseptic
21
Q
easily altered, decomposed, or destroyed by heat
A
thermolabile
22
Q
not easily altered, decomposed or destroyed by heat
A
thermostable
23
Q
Overall degree of microbial resistance to killing (most to least)
A
1) Bacterial Endospores
2) Mycobacteriam
3) Protozoan cysts
4) Non-enveloped small viruses
5) Vegetative bacteria
6) Fungi
7) Enveloped viruses
24
Q
more resistant to antimicrobial control methods than all other microbial forms
A
Bacterial endospore
25
microbes are not killed instantly when exposed to lethal agents, but more dysfunctional and die over time. Vegetative cells die more rapidly than spores
microbial death
26
which die first... vegetative cells or spores?
vegetative die first
27
a larger quantity of contaminating microbes requires a longer exposure time to destroy
population size
28
usually increase chem concentration increase micro-org death. Some agents are more effective at lower concentrations
concentration/Intensity of antimicrobial
29
the longer a population is exposed to a microbicidal agent, the more organisms are killed
duration of exposure
30
High temps can inactivate enzymes and denature molecules--- chem disinfectants may function better/faster at increased temps.
Strong acids can directly kill microbes; weak acid may enable chemicals to inactivate microbes faster
Temperature and pH
31
organic matter can protect micro-org from heating and chemical disinfectants
presence of protective or neutralizing matter
32
Modes of Action of Microbial Control Methods
Damage to cell wall
Disrupt cytoplasmic membrane
Inhibit synthesis of proteins and nucleic acids
Alter function of proteins & nucleic acids
33
a. Block its synthesis, digest it, or break down its surface b. Examples: antibiotics, lysozyme, detergents
Damage to cells wall
34
a. Cause loss of membrane integrity and selective permeability
b. Example: detergents (surfactants), heat
Disrupt cytoplasmic membrane
35
a. Interference with gene translation, thus preventing protein synthesis
b. Examples: antibiotics, radiation, formaldehyde
Inhibit synthesis of proteins and nucleic acids
36
a. Alter bonds that determine secondary and tertiary structure. Altered structure inactivates or denatures functions of enzymes and nucleic acids.
b. Examples: heat, strong organic solvents, phenolics, metallic ions, antibiotics
Alter function of proteins & nucleic acids
37
a. Refrigeration -- slows metabolism of microbes, but does not kill most microbes. Used for prolonging storage and shelflife of foodstuffs, vaccines, blood, medications, etc.
b. Freezing (especially ultra-low, -70°C) -- essentially stops metabolism, but does not kill microbes. Used for long-term storage of microbes and serum.
Cold Temperatures ( Physical Control Method)
38
Methods of PHYSICAL control of Microorganisms
Cold Temperatures
Heat
Radiation
Filtration
39
a. Heat kills cells by disrupting cell membrane functions, denaturing proteins, and inactivating nucleic acids.
(1) Cell membranes become more fluid at elevated temperatures, causing them to lose their
selective permeability.
(2) Proteins (e.g. enzymes) and nucleic acids are inactivated by breaking their hydrogen bonds,
which unfolds proteins and separates double-stranded nucleic acids.
b. Limited to heat-resistant materials. Sterilization depends on temperature, duration of heating, and
humidity.
c. Moist heat is more effective than dry heat
(1) Moist heat possesses greater heat energy than dry heat
(2) Boiling doesn't kill bacterial endospores which may survive hours of boiling.
Heat (Physical Control of micro-org)
40
___ is more effective than dry heat
Moist heat
41
possesses greater heat energy: dry heat or moist heat?
moist heat
42
how to attack proteins and nucleic acids?
breaking their hydrogen bonds (heat)
43
(1) Conditions -- 160 to 180°C for two hours.
(2) Disadvantages of dry heat oven
(a) Liquids cannot be heated above boiling point (100°C) without undergoing excessive evaporation and boil over.
(b) Organic compounds may denature above certain temperatures, e.g. 160°C.
(3) Used for thermostable non-liquid, e.g. metal or glass
Dry heat (hot air oven)
44
hot air oven?
dry heat
45
(1) Conditions
(a) 121°C for 15 minutes (minimum time required to ensure killing viable organisms and spores). Large loads may require more than 1 hour so that moist heat can penetrate to all items in the load.
(b) The high pressure in the autoclave counteracts vaporization (i.e. boiling) so that heat- stable liquids can be heated to 121°C under 15 lb of pressure without boiling over. High pressure does not cause the killing.
(2) Limitations
(a) Cannot be used for certain thermolabile substances
(b) Cannot be used for items adversely affected by moisture; i.e. surgical instruments with sharp cutting edges, dry chemicals, etc.
3) Uses
(a) Sterilization of clean, wrapped instruments, containers & microbial culture media
(b) To render contaminated materials biologically safe before they are discarded
Steam heat (steam under pressure, AUTOCLAVE)
46
The burning of organic material destroys living cells; used for small metal or glass instruments in the laboratory and on medical wastes at the facility or installation level.
High temperature (e.g. 1800F) reduces waste to ash within several seconds; industrial size processes up to 1000 kg/hour.
incineration
47
Heat methods:
Heat, moist heat, dry heat, steam heat, incineration
48
a. Ionizing radiation -- Gamma
(1) Nonspecifically alters cellular proteins and nucleic acids by penetrating deep into objects.
(2) Used to sterilize pharmaceuticals, medical/dental supplies, and items that cannot withstand the heat of steam sterilization or the effects of chemicals
b. Ionizing radiation – Electron Beam Radiation
(1) Alters nucleic acid
(2) Used to decontaminate packages, e.g. by Postal Service for mail, industry for medical items
c. Non-ionizing radiation -- Ultraviolet
(1) Nucleic acids mutations that prevent normal gene expression and DNA replication.
(2) Optimum wave length -- 240 to 280 nm (Optimum 254 nm).
(3) Low penetrating power - Must have direct contact with organism.
(4) Requires lengthy exposure, e.g. 10 seconds to 30 minutes depending on distance from UV
light source.
Radiation
Ionizing --- Gamma and Electron Beam
Non-ionizing--- Ultraviolet
49
a. Membrane micropore filters – membrane of cellulose acetate & cellulose nitrate has complex
system of pores that trap microbes by pore size and chemical affinity to the matrix
(1) Pore size of 0.22 micron is usually effective in removing all bacteria (i.e. sterilization).
(2) Moderately effective on viruses, mycoplasma, chlamydia, and rickettsia.
(3) Used for sterilization of thermolabile liquids.
b. High-Efficiency Particulate Air (HEPA) filtration
(1) HEPA filters consist of randomly oriented glass and polymer fibers that effectively remove
99.97% of particles 0.3um and larger.
(a) They are also highly effective at containing particles between 0.3 and 0.1 um (100
nanometers) and smaller. (Highly effective for blocking bacteria; moderately effective for blocking viruses)
(b) Most bacteria and viruses exist in clumps, thus are larger than the pore size
(c) Removal of particles is accomplished by adherence of particles to the fibers rather than
by sieve in common paper filters.
(2) Uses
(a) Air filters for respiratory protection
i. Mask: N95, not routine surgical or painters mask ii. PAPR: Powered Air Purifying Respirator – includes HEPA filter, blower, hood
(b) Biological safety cabinet -- A contained work area designed to prevent exposure to infectious aerosols and to protect materials and specimens from environmental contamination. Airflow carries particulate matter away from the user and into an area of filtration, and it prevents the outflow of infectious agents. (NOT same as chemical fume hood)
Filtration
50
Table 2 - Physical Control
Learn it!
51
Methods of Chemical Control of Microorganisms
1. Levels of disinfectant activity (not a prefect classification)
a. High-level disinfectants -- microbicidal and sporocidal, although some may do so slowly;
effectiveness approaches sterilization. Some may be sterilants under appropriate conditions.
b. Intermediate-level disinfectants -- (effectiveness varies within category) – [Most commonly
employed products] - effective against vegetative forms of bacteria and may be effective against
fungi and viruses (microbicidal -- tuberculocidal, fungicidal, virucidal), but few products will be sporocidal. A few are antiseptics.
Antiseptic – chemical disinfectant agent; method that may be safely used on skin; tissue
c. Low-level disinfectants -- usually (but not always) bactericidal; not sporocidal or tuberculocidal,
often not fungicidal or virucidal.
2. Soap
a. Moderately effective as a disinfectant in infection control by mechanical removal of microbes
through frequent handwashing
b. Washing for at least 15 seconds with soap and water provides reasonable effectiveness.
c. Bactericidal soap is not worthwhile, and several ingredients have been banned.
52
Mechanisms of action of antimicrobics -- note unique target sites of procaryotic cells
1. Introduction to antimicrobic concepts
a. Antibiotic / Antimicrobic agent (antimicrobic): a chemical substance of natural, semisynthetic, or
synthetic origin that inhibits or kills microorganisms and which can be used to treat or control
infection.
b. Selective toxicity -- the antibiotic will affect only the target organism (microbe) without harming the
host (patient) [although mild toxicity or side effects are considered acceptable]
2. Inhibitors of cell wall synthesis
a. Beta-lactam antibiotics (use this mechanism of action)
(1) The antibiotic activity of these compounds
depends on the integrity of the beta-lactam ring
(O=C-N). By altering the nature of the side
chains (R), differences in antimicrobic properties
can be obtained.
(2) Examples
(a) Penicillins (e.g. Pen G, ampicillin, methicillin,
carbenicillin, piperacillin) (b) Cephalosporins (e.g. cephalothin, cefoxitin, ceftazadime)
(3) Principle of action -- inhibits peptidoglycan synthesis by inhibiting the formation of crosslinks
between the polymers of the bacterial cell wall
(a) Peptidoglycan synthesis consists of about 30 enzymatic steps to synthesize long
polysaccharide chains of N-acetyl-glucosamine (NAG) & N-acetyl-muramic acid (NAM); and to cross link them by short peptides
(b) Penicillin binding proteins (PBP) are cell-membrane enzymes (proteins) responsible for
synthesizing peptidoglycan
(c) Beta-lactam antibiotics act by binding to PBPs. (d) Results in:
i. Inhibition of peptidoglycan synthesis
ii. Degradation of formed cell wall through the release of autolytic enzymes
iii. Weakened cell wall loses integrity and can no longer preserve osmotic pressure.
Results in cell death and increased phagocytosis.
(4) Major characteristics of Beta-lactams
(a) Acts poorly against existing peptidoglycan, so primarily effective against actively growing
bacteria
(b) Most effective against gram-positive bacteria because the outer membrane of gram-
negatives prevents some degree of antibiotic entrance (c) Very low toxicity (d) Generally bactericidal (e) Different groups/generations of antibiotics have different spectrums and resistance
(f) Resistance can occur due to:
i. Development of changes to pores thus preventing entrance of antibiotic
ii. Prevention of binding of antibiotic to PBP due to modified PBP structure
iii. Hydrolysis of antibiotic by beta-lactamases (penicillinase, cephalosporinase)
b. Vancomycin -- binds onto the cross-link peptide, so that the link cannot be completed and peptidoglycan polymer cannot elongate
c. Bacitracin -- blocks phospholipid carrier that helps carry subunits of peptidoglycan across membrane
to cell wall
d. Isoniazid (INH) -- inhibits formation of mycolic acid in cell walls of mycobacterium (tuberculosis
organism)
Inhibitors of cell wall synthesis
53
Inhibitors of cell wall synthesis
Beta-lactam antibiotics
Vancomycin
Bacitracin
Isonizid (INH)
54
Inhibitors of protein synthesis
a. Principle -- inhibits accurate translation of mRNA or polypeptide chain formation at the bacterial
ribosome
b. Examples and indications for use
(1) Chloramphenicol, clindamycin -- inhibits the polypeptide elongation steps in translation by
binding to 50S ribosome subunit and blocking peptide bond formation
(a) Bacteristatic
(b) Broad-spectrum
(c) Resistance is primarily due to chemical alteration of either the antibiotic or the ribosomal molecule, thus preventing binding
(2) Macrolides (e.g. erythromycin) – binds to 50S subunit; prevents translocation (3) Aminoglycosides (e.g. gentamycin, tobramycin) -- inhibit translation by binding to 30S ribosomal protein causing misreading of mRNA and incomplete synthesis of protein molecules
(a) Bactericidal
(b) Broad-spectrum, although predominately used against various systemic gram-negative
infections (c) Resistance most commonly results from enzymatic modification of the antibiotic
(4) Tetracyclines -- inhibits translation into polypeptides (proteins) by blocking binding of tRNA to
the 30S ribosome-mRNA complex
(a) Bacteristatic
(b) Broad-spectrum
(c) Resistance most commonly results from active efflux of the antibiotic out of the cell or the
production of proteins that protect the 30S ribosome
55
Inhibitors of cell membrane function
a. Principle -- disrupts functional integrity of cytoplasmic membrane, allowing nucleotides and proteins to escape (detergent-like)
b. Polymyxins -- active against gram-negatives, but nephrotoxicity limits them to external use
c. Amphotericin B (a polyene) -- antifungal; binds with ergosterol in fungal membranes; somewhat toxic
56
Inhibitors of nucleic acid
| synthesis
a. Principle -- competitive inhibition of essential nucleic acid precursor or binds essential enzyme (e.g. DNA gyrase)
b. Typical examples
(1) Quinolones (e.g. nalidixic acid) and Fluoroquinolones
(e. g. ciprofloxacin) -- inhibit bacterial DNA gyrase (the enzyme that controls DNA coiling -- if DNA is not tightly coiled, it will not fit into the bacterial cell)
(2) Rifampin -- inhibits transcription by binding to RNA polymerase and inhibiting initiation of mRNA synthesis
(3) Metronidazole -- causes breakage of microbial DNA (bacterial and parasitic DNA)
(4) Nucleoside analogues -- antiviral antimicrobics
(a) Inhibit DNA or RNA synthesis by altering their composition using nucleic acid analogues (structurally similar chemicals which inactivate the DNA or RNA)
(b) Examples -- Acyclovir, Ribavirin, Zidovudine
5) Flucytosine, 5-fluorocytosine (5FC) -- incorporates into fungal RNA and interferes with DNA
and protein synthesis
c. Most are bactericidal and moderately narrow spectrum
d. Resistance is typically because of decreased uptake into the cells due to cell wall or cell membrane molecular changes
57
Inhibitors of bacterial metabolism (antimetabolite)
Sulfonamides
Trimethoprim
Azoles
a. Sulfonamides (sulfamethoxazole) -- inhibits folic acid synthesis by competing for precursor molecules
b. Trimethoprim -- competitively interferes with folic acid production by inhibiting a metabolic enzyme c.
Azoles (fluconazole) -- antifungal -- inhibits synthesis of ergosterol, a key structural molecule of fungal cell membranes
58
inhibitors of cell wall synthesis
Beta Lactam Abx
Vancomycin
Bacitracin
Isoniazad
59
inhibitors of protein synthesis
Chloramphenicol & clindamycin
Macrolides (erythromycin)
Aminoglycasides (gentamycin, tobramycin)
Tetracyclines
60
Inhibitors of cell membrane function
Polymyxins
| Amphotericin B
61
Inhibitors of nucleic acid sythesis
```
Quinolones
Rifampin
Metronidazole
Nucleoside Analogues (Acyclovir, Ribavirin, Zidovudine)
Flucytosine, 5-fluorocytosine (5FC)
```
62
inhibitors of bacterial metabolism (antimetabolite)
Sulfonamides (sulfamethoxazole)
Trimethoprim
Azoles (fluconazole)
63
Non-enveloped or enveloped virus harder to kill?
why?
non-enveloped harder to kill!
Because enveloped virus have envelope made from human cell membrane or lipid bilayer.... which is easy to destroy with organic solvents
64
which dies more rapidly, spores or vegetative cells?
vegetative cells die more rapidly than spores
65
Abx Inhibitors of Protein synthesis sites of action
50S and 30S subunits
50S (CEC)
Chloramphenicol
Erythromycin
Clindamycin
```
30S (SAAT)
Streptomycin
Aminoglycosides
Amikacin
Tetracycline
```
66
Cell membrane Abx
Polymyxins
| Amphotericin B
67
Cell Wall Abx (synthesis and repair blocking drugs)
Bacitracin
Beta Lactams - Cephalosporins / Penicillins
Isoniazid (INH)
Vancomycin
68
DNA Abx
```
Inhibit Gyrase (unwinding enzymes) (GQ)
Quinolones (ciprofloxacin)
```
Inhibit RNA polymerase
Rifampin
69
Cytoplasm / metabolism Abx
Inhibit folic acid metabolism (ST)
SULFONamides (Sulfa drugs)
Trimethoprim
70
Beta Lactam Abx means? differences between? Ex's?
O=C-N
work differently by altering nature of side chains (R)
Penicillins & Cephalosporins
Penicillins
Pen G, ampicillin, methicillin, carbenicillin, piperacillin)
Cephalosporins
cephalothin, cefoxitin, ceftazadime
71
Principle of Action for Beta Lactam Abx
inhibits peptidoglycan synthesis by inhibiting the formation for crosslinks between the polymers of the bacterial cell wall
a. Peptidoglycan 30 steps
b. PBP (penicillin binding proteins) - are cell-membrane enzymes (proteins) responsible for synthesizing Peptidoglycan
c. Beta-Lactam Abx act by binding to PBP's
72
Result of Beta-Lactam Abx binding to PBP's
i. inhibtion of peptidoglycan synthesis
ii. degredation of formed cell wall through release of autolytic enzymes
iii. weakened cell wall loses integrity and can no longer preserve osmotic pressure --> cell death and increased phagocytosis
73
Major characteristics of Beta-Lactams
a. Exists poorly against EXISTING peptidoglycan (targets GROWING bacteria)
b. MOST effective with Gram +
c. very LOW toxicity
d. generally bactericidal
e. Abx face resistance
f. resistance can occur due to:
i. development of changes to pores (preventing entrance of abx)
ii. prevention of binding of Abx to PBP (modified PBP structure)
iii. Hydrolysis of Abx by Beta-lactamases (penicillinase, cephalosporinase)
74
Abx Beta Lactam resistance can occur due to:
i. development of changes to pores (preventing entrance of abx)
ii. prevention of binding of Abx to PBP (modified PBP structure)
iii. Hydrolysis of Abx by Beta-lactamases (penicillinase, cephalosporinase)
75
binds to the cross-link peptide, so that the link cannot be completed and peptidoglycan polymer cannot elongate
vancomycin
76
blocks phospholipid carrier that helps carry subunits of peptidoglycan across membrane to cell wall
bacitracin
77
inhibits formation of MYCOLIC ACID in cell walsl of mycobacterium (TUBERCULOSIS organism)
Isoniazid (INH)
78
inhibits accurate translation of mRNA or polypeptide chain formation at the bacterial ribosome
Inhibitor of protein synthesis (30S and 50S)
79
inhibits the polypeptide elongation steps in translation by binding to 50S ribosome subunit and blocking peptide bond formation
Chloramphenicol, clindamycin
- bacteriostatic
- broad spectrum
- resistance due to chemical alteration of ABX or ribosomal molecule (prevent binding)
80
binds to 50S subunit; prevents TRANSLOCATION
Macrolides (erythromycin)
81
Inhibits translation by binding to 30S ribosomal protein causing misreading of mRNA and incomplete proteins
Aminoglycosides (gentamycin, tobramycin)
- bacteriocidal
- broad spectrum
- resistance from enzymatic modification of ABX
82
inhibits translation into polypeptides (proteins) by blocking binding of tRNA to the 30S ribosome
Tetracyclines
- bacteristatic
- broad spectrum
- resistance from active efflux of ABX out of the cell or production of proteins to protect 30S ribosome
83
Inhibitors of cell membrane function abx
PA
Polymyxins (gram -, but NEPHROTOXIC to external use
Amphotericin B - antifungal - binds with ergosterol in fungal membranes
84
Inhibitors of nucleic acid synthesis abx types
```
QRMN (QueeR MeN)
Quinolones
Rifampin
Metronidazole
Nucleoside analogues
```
85
Inhibitors of nucleic acid synthesis abx principle
competitive inhibition of essential nucleic acid precursor or binds essential enzyme
86
inhibit bacterial DNA gyrase (enzyme controlling coiling)
Quinolones and Fluoroquinolones
87
inhibits TRANSCRIPTION by binding to the RNA polymerase and inhibiting initiation of mRNA synthesis
Rifampin
88
causes breakage of microbial DNA (bacterial and parasitic DNA)
Metronidazole
89
antirviral antimicrobics (Nucleoside analogues) work by?
Ex's?
inhibit DNA or RNA synthesis by altering their composition using nucleic acid analogues
Ex's: Acyclovir, Ribavirin, Zidovudine
90
Incorporates into fungal RNA and interferes with DNA and protein synthesis
Flucytosine, 5-flurocytosine (5FC)
91
Inhibitors of bacterial metabolism (antimetabolite)
SAT
Sulfonamides
Trimethoprim
Azoles
Sulfonamides (sulfamethoxazole) -- inhibits folic acid synthesis by competing for precursor molecules
Trimethoprim -competitively interferes with folic acid production by inhibiting a metabolic enzyme
Azoles (fluconazole) -- antifungal - inhibits synthesis of ergosterol, key structural component of fungal cell membranes
92
-- inhibits folic acid synthesis by competing for precursor molecules
Sulfonamides (sulfamethoxazole)
93
-competitively interferes with folic acid production by inhibiting a metabolic enzyme
Trimethoprim
94
-- antifungal - inhibits synthesis of ergosterol, key structural component of fungal cell membranes
Azoles (fluconazole)
95
action: disrupts structural proteins & enzymes
kills vegetative bacteria within minutes & spores in 3-10 hr; active solution unstable
Glutaraldehyde, 2-5% aqueous - High disinfectant, Y Sterilant (Sporocidal)
96
action: formation of hydroxyl free radicals which are toxic to cells
stays for several weeks. Vaporized sterilization -- about 6 hr. Disinfection - about 2-30 minutes
hydrogen peroxide
vaporized, 25% (High disinfectant, Y Sporocidal)
Aqueous, 3% (Int disinfectant)
97
Action: Disrupts cell walls & membranes; precipitates proteins
Kills vegetative bacteria within a few minutes; Stable. DIsinfection - about 2 - 30 minutes. Skin irritant.
Phenolic compounds
INT disinfectant, corrosive
98
Action: inactivates enzymes; damages membranes
Fast action; Skin & lung irritant (Gas highly toxic); bleach decomposes w/ in a few dasy (prepare fresh every 2-3 days: High Level Disinfection - about 1-6 hrs. Normal disinfection 2-30 minutes.
chlorine compounds
- gaseous, 100-1000 ppm
- hypochlorite (1:10% dilution of bleach)
99
when you see Mycobacterium tuberculosis, Brucella spp THINK
BSL-3
100
Action: Metabolic enzymes (disrupts)
Disinfection: 2-30 min
Iodophors (eg 1-10% povidone-iodine)
Antiseptic & inactivated by organic material
101
Action: dissolves membrane lipids; may coagulate protein
inactivated somewhat by organic matter; mild skin & lung irritant; dries skin; flammable. Disinfectant - about 1-10 min
Alcohol
70% isopropyl or ethyl
(including hand sanitizers)
102
surfactant, destroys cell membrane; denatures proteins
Quarternary ammonium compounds (TOXIC if ingested)
Chlorhexidine, 4% (Low toxicity!)
