Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
48 Cards in this Set
- Front
- Back
nosocomial infections
|
hospital-acquired infections
before aseptic techniques caused death in at least 10% of surgical patients and up to 25% of delivering mothers |
|
thermal death point (TDP)
|
the lowest temperature at which all the microorganisms in a particular liquid suspension will be killed in 10 minutes
|
|
thermal death time (TDT)
|
the minimal length of time for all bacteria in a particular liquid culture to be killed at a given temperature
|
|
moist heat
|
kills primarily by coagulating proteins
protein denaturation |
|
boiling
|
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 |
|
reliable sterilization with moist heat
|
steam under pressure;autoclave
the higher the pressure, the higher the temperature;usually set for 15 min. At 15 psi (121oC) |
|
Pasteurization
|
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 |
|
classic pasteurization
|
63oC for 30 minutes
|
|
high-temperature short-time pasteurization (HTST)
|
72oC for 15 seconds
milk flows past a heat exchanger kills pathogens and lowers total bacterial count |
|
ultra-high-temperature treatments (UHT)
|
sterilizes
fluid rapidly heated to 140oC for 3 seconds then rapidly cooled can be stored at room temperature Not pasteurization |
|
filter sizes - pore sizes;0.22-0.45 m
|
traps most bacteria
maybe not spirochetes and mycoplasmas |
|
Listeria monocytogenes
|
listeriosis;gram-positive rod (but produces endotoxin)
causes stillbirth and neurological disease in humans and other animals |
|
lyophilization
|
freeze-drying
certain foods are freeze-dried coffee, some fruit additives for dry cereals |
|
Deinococcus
|
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.
|
|
phenol
|
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% |
|
Phenolics
|
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 |
|
O-phenylphenol
|
main ingredient in most formulations of Lysol
|
|
Para-tertiary amylphenol
|
used as a demulsifyer, biocide and in fragrances; an active ingredient of Birex a one-step germicidal detergentused to disinfect countertops
|
|
bisphenols
|
contain two phenolic groups connected by a bridge
|
|
hexachlorophene
|
in pHisoHex
very good against gram positive staphylococci and streptococci used to wash newborns excessive use can lead to neurological damage |
|
triclosan
|
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 |
|
Pseudomonas aeruginosa
|
a gram-negative bacterium is very resistant to triclosan
|
|
biguanide
|
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.
|
|
chlorhexidine
|
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 |
|
iodine
|
one of the oldest and most effective antiseptic
possible mechanism combines with certain amino acids |
|
tincture
|
in solution in aqueous alcohol
|
|
chlorine
|
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 |
|
calcium hypochlorite
|
[Ca(OCl)2] (chloride of lime)
|
|
sodium hypochlorite
|
NaOCl (bleach)
|
|
chlorine dioxide - ClO2
|
gaseous
used for area disinfection used to kill endospores of anthrax bacterium in buildings Used in food processing; does not leave residue or odor |
|
chloramines
|
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 |
|
alcohols
|
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 |
|
heavy metals
|
silver, mercury, copper
oligodynamic action ability of very small amounts to exert antimicrobial activity combine with sulfhydryl groups on amino acids; denature proteins |
|
silver
|
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 |
|
surface active agents
|
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 |
|
quaternary ammonium compounds
|
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 |
|
sodium nitrate and sodium nitrite
|
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 |
|
aldehydes
|
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 |
|
formaldehyde
|
formalin - 37% aqueous solution of formaldehyde gas
once extensively used to preserve biological specimens still used to inactivate bacteria and viruses in vaccines |
|
glutaraldehyde
|
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 |
|
ethylene oxide
|
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 |
|
plasmas
|
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 |
|
ozone
|
(O3)
generated by passing oxygen through high-voltage electrical discharges used in the disinfection of water expensive |
|
hydrogen peroxide
|
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) |
|
peracetic acid
|
most effective liquid chemical sporicide
sterilant many applications food processing, medical equipment leaves no toxic residues |
|
Pseudomonas and Burkholderia of special interest
|
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 |
|
groups of resistant microbes
|
mycobacteria
waxy. Lipid-rich component in cell wall endospores affected by relatively few biocides cysts and oocysts of protozoa |
|
prions
|
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 |