Chapter 7 Micro

Front 1

nosocomial infections

Back 1

hospital-acquired infections
before aseptic techniques caused death in at least 10% of surgical patients and up to 25% of delivering mothers

Front 2

thermal death point (TDP)

Back 2

the lowest temperature at which all the microorganisms in a particular liquid suspension will be killed in 10 minutes

Front 3

thermal death time (TDT)

Back 3

the minimal length of time for all bacteria in a particular liquid culture to be killed at a given temperature

Front 4

moist heat

Back 4

kills primarily by coagulating proteins
protein denaturation

Front 5

boiling

Back 5

kills vegetative forms of bacterial pathogens, almost all viruses, fungi and their spores in 10 minutes or less
hepatitis virus can survive up to 30 minutes
endospores can survive more than 20 hours
brief boiling even at high altitudes will kill most pathogens

Front 6

reliable sterilization with moist heat

Back 6

steam under pressure;autoclave
the higher the pressure, the higher the temperature;usually set for 15 min. At 15 psi (121oC)

Front 7

Pasteurization

Back 7

developed to prevent spoilage in beer and wine
mild heating sufficient to kill organisms that cause spoilage without seriously damaging the taste of the product
used also in milk
intent is to lower microbial numbers which prolongs milk’s good quality under refrigeration
thermoduric (heat resistant) bacteria survive, but unlikely to cause disease or cause refrigerated milk to spoil

Front 8

classic pasteurization

Back 8

63oC for 30 minutes

Front 9

high-temperature short-time pasteurization (HTST)

Back 9

72oC for 15 seconds
milk flows past a heat exchanger
kills pathogens and lowers total bacterial count

Front 10

ultra-high-temperature treatments (UHT)

Back 10

sterilizes
fluid rapidly heated to 140oC for 3 seconds
then rapidly cooled
can be stored at room temperature
Not pasteurization

Front 11

filter sizes - pore sizes;0.22-0.45 m

Back 11

traps most bacteria
maybe not spirochetes and mycoplasmas

Front 12

Listeria monocytogenes

Back 12

listeriosis;gram-positive rod (but produces endotoxin)
causes stillbirth and neurological disease in humans and other animals

Front 13

lyophilization

Back 13

freeze-drying
certain foods are freeze-dried
coffee, some fruit additives for dry cereals

Front 14

Deinococcus

Back 14

All members of the genus Deinococcus are very resistant to ionizing radiation (IR). They can survive 10,000 Gy, while a human would be killed by 8 Gy. Gy (gray) is the absorption of one joule of radiation energy by one kilogram of matter.

Front 15

phenol

Back 15

carbolic acid
Lister used it
now rarely used
still used in throat lozenges for its local anesthetic effect
antibacterial effect in throat sprays at concentrations above 1%

Front 16

Phenolics

Back 16

derivatives of phenol;phenol altered to reduce irritating qualities and increase antibacterial activity
often combines with soap or detergent
injure lipid membranes and walls of mycobacteria
remain active in presence of organic compounds
stable, persist
cresols - derived from coal tar

Front 17

O-phenylphenol

Back 17

main ingredient in most formulations of Lysol

Front 18

Para-tertiary amylphenol

Back 18

used as a demulsifyer, biocide and in fragrances; an active ingredient of Birex a one-step germicidal detergentused to disinfect countertops

Front 19

bisphenols

Back 19

contain two phenolic groups connected by a bridge

Front 20

hexachlorophene

Back 20

in pHisoHex
very good against gram positive staphylococci and streptococci
used to wash newborns
excessive use can lead to neurological damage

Front 21

triclosan

Back 21

another bisphenol;in antibacterial soaps and one toothpaste
incorporated into plastic kitchen cutting boards and handles of knives and other plastic kitchenware
resistant bacteria have been reported
inhibits enzyme needed for biosynthesis of fatty acids
especially effective against gram-positive bacterial

Front 22

Pseudomonas aeruginosa

Back 22

a gram-negative bacterium is very resistant to triclosan

Front 23

biguanide

Back 23

can refer to a molecule, or to a class of drugs based upon this molecule. Biguanides can function as oral antihyperglycemic drugs used for diabetes mellitus or prediabetes treatment. They are also used as antimalarial drugs.

Front 24

chlorhexidine

Back 24

biguanides;broad spectrum
combined with detergent or alcohol
surgical hand scrubs, preoperative skin preparation
strong affinity for binding to the skin or mucous membranes
injures plasma membrane
mycobacteria relatively resistant
endospores and protozoan cysts not affected
only enveloped viruses affected

Front 25

iodine

Back 25

one of the oldest and most effective antiseptic
possible mechanism
combines with certain amino acids

Front 26

tincture

Back 26

in solution in aqueous alcohol

Front 27

chlorine

Back 27

forms hypochlorous acid (HOCl) with water
strong oxidizing agent that prevents much of the cellular enzyme system from functioning
neutral in electrical charge and diffuses as rapidly as water through the cell membrane?
Used to disinfect municipal drinking water, water in swimming pools and sewage

Front 28

calcium hypochlorite

Back 28

[Ca(OCl)2] (chloride of lime)

Front 29

sodium hypochlorite

Back 29

NaOCl (bleach)

Front 30

chlorine dioxide - ClO2

Back 30

gaseous
used for area disinfection
used to kill endospores of anthrax bacterium in buildings
Used in food processing; does not leave residue or odor

Front 31

chloramines

Back 31

chlorine and ammonia
very stable
effective in organic matter
act slowly
used to sanitize glassware and eating utensils and to treat dairy and food-manufacturing equipment
used in municipal water-treatment - helps control taste and odor
toxic to aquarium fish

Front 32

alcohols

Back 32

kill bacteria and fungi but not endospores and nonenveloped viruses
protein denaturation and disrupt plasma membranes
evaporates and leaves no residue
degerming before an injection
unsatisfactory for treating wounds
coagulates proteins behind which bacteria grow
pure ethanol less effective than 60-95%
isopropanol better than ethanol
Zephiran (quat in alcohol [tincture]) better than in water

Front 33

heavy metals

Back 33

silver, mercury, copper
oligodynamic action
ability of very small amounts to exert antimicrobial activity
combine with sulfhydryl groups on amino acids; denature proteins

Front 34

silver

Back 34

1% silver nitrate solution
used to be put in eyes of newborns
gonorrheal ophthalmia neonatorum
silver-impregnated dressings, indwelling catheters
Silver thread in military uniforms
Used as bandages
silver-sulfadizine - topical cream for use on burns
surfacine - silver iodide and biguanide - not yet approved

Front 35

surface active agents

Back 35

surfactants;decrease surface tension soaps and detergents
soaps
little antiseptic value
function to help mechanical removal
emulsification - good degermers
detergents - acid-anionic surface active sanitizers
damages plasma membrane

Front 36

quaternary ammonium compounds

Back 36

cationic detergents
most widely used surface-active agents
modifications of the four-valence ammonium ion
strongly bacteriocidal against gram-positive bacteria, fungicidal, amoebicidal, virucidal (enveloped)
do not kill endospores or mycobacteria
Zephiran - benzalkonium chloride
Cepacol - cetylpyridinium chloride
Approved as an antimicrobial wash in poultry processing (FDA);certain bacteria (Pseudomonas and Burkholderia) can actively grow in them

Front 37

sodium nitrate and sodium nitrite

Back 37

in many meat products
ham, bacon, hot dogs, sausage
bacteria can convert sodium nitrate to sodium nitrite the active ingredient
nitrate reduced to nitrite in anaerobic respiration
functions
red color (reacts with blood components)
prevents germination and growth of botulism endospores (Clostridium botulinum); inhibits iron containing enzymes

Front 38

aldehydes

Back 38

most effective antimicrobials
formaldehyde and glutaraldehyde
inactivate proteins by forming covalent cross-links with several organic functional groups
amino group, hydroxyl group, carboxyl group, sulfhydryl group

Front 39

formaldehyde

Back 39

formalin - 37% aqueous solution of formaldehyde gas
once extensively used to preserve biological specimens
still used to inactivate bacteria and viruses in vaccines

Front 40

glutaraldehyde

Back 40

less irritating, more effective
Cidex -2% solution
used to disinfect hospital instruments
sporicidal in 3-10 hours
could almost be considered a sterilizing agent
used by morticians for embalming
used as a fixative by electron microscopists

Front 41

ethylene oxide

Back 41

denatures proteins
hydrogens on sulhydryl groups and carboxyl groups are replaced by alkyl groups (-CH2 CH2OH)
alkylation
4-18 hours
toxic and explosive - mixed with carbon dioxide or nitrogen
used to sterilize spacecraft, mattresses
no heat required

Front 42

plasmas

Back 42

A state of matter in which a gas is excited (by an electromagnetic field) to make a mixture of nuclei with assorted electrical charges and free electrons
A partially ionized gas with some free electrons
Electrically conductive
Distinct state of matter separate from gas, liquid, solid
Hydrogen peroxide plasmas

Front 43

ozone

Back 43

(O3)
generated by passing oxygen through high-voltage electrical discharges
used in the disinfection of water
expensive

Front 44

hydrogen peroxide

Back 44

may slow wound healing
quickly broken down to water and oxygen gas by catalase (present in human cells)
effect on inanimate objects - sporicidal at elevated temps
aseptic packaging, cleaning contact lenses (platinum catalyst removes)

Front 45

peracetic acid

Back 45

most effective liquid chemical sporicide
sterilant
many applications
food processing, medical equipment
leaves no toxic residues

Front 46

Pseudomonas and Burkholderia of special interest

Back 46

unusually resistant to biocides
grow actively in some disinfectants and antiseptics
most notably in the quaternary ammonium compounds
also resistant to many antibiotics
porins - openings in outer membrane of gram-negative bacteria - highly selective

Front 47

groups of resistant microbes

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mycobacteria
waxy. Lipid-rich component in cell wall
endospores
affected by relatively few biocides
cysts and oocysts of protozoa

Front 48

prions

Back 48

special problem
infectious proteins - spongiform encephalopathies
normal autoclaving inadequate
Recommended by CDC and WHO
Combine use of sodium hydroxide and autoclaving at 134oC
Use of proteases
Use of disposable instruments