Microbiology Chapter 7

"Why do they take the baby to the mother first? She had him for 9 months. Share!"

"His head was so messed up. His eyes were closed but his face was facing me like I'm scared" "They tried to cover it up, put a little hat"

How John learned about spray tanning...

"I'm not gonna say her name, Stacy, came in one day looking like a punkin"

We in Connecticut, if you see something, say something.

(John on the topic of handwashing)

What factors are important to effective disinfection?

*Concentration of disinfectant Organic matter pH Time *There are exceptions: 100% alcohol is not as effective as 70%, it needs water

Factors that affect effectiveness of treatment?

-Number of microbes -Environment -Time of exposure -Microbial characteristics

Ionizing radiation is used for...

-gamma radiation penetrates deep into objects -destroys bacterial endospores; not always effective against viruses -used for sterilization and pasteurization of antibiotics, hormones, sutures, plastic disposable supplies, and food

HEPA stands for

A filter NOT for water, for air High-efficiency particulate air

_____ is talking about living tissue

Antisepsis

_____ - proteins produced by one bacterium that inhibits another

Bacteriocins

Norovirus, what happens if you get it?

Beware of the tongs on cruise ships Bad things

*Chlorhexidine is a _____ that you might see in your hospital as _____

Biguanide; hibiclens (a presurgical cleaner, could also come in a mouthwash variety)

_____ : hypochlorous acid (HOCl)

Bleach

Steam or boiling water, if you had to stick your finger in one, which would hurt less or do the least damage?

Boiling water

How does UV light do damage?

Causes thymine dimers, preventing replication and transcription

_____ = chlorine + ammonia

Chloramine

_____ used in water systems, if you live too far from system you might not get enough. Activated by the sun, doesn't behave very well as temperatures go up

Chlorine Don't go in a hot tub when you smell chlorine, you smell it but there's not enough of it in the water. Use bromine in your hot tub not chlorine, it''s more stable

All canned goods in stores have been _____ to protect from _____ endospores

Commercial sterilization, C. botulinum

Sodium nitrate and sodium nitrite are added to many meat products, such as ham, bacon, hot dogs, and sausage. These additives help to prevent the growth of Clostridium botulinum by inhibiting certain iron-containing enzymes of the organism. This is an example of chemical food preservation. Which of the following correctly describes a method of chemical control used to control microbial growth?

Correct There are multiple types of chemical agents that can be used to disinfect body tissues or inanimate objects. When choosing an agent, one should consider the groups of organisms that the disinfectant is effective against, the effective concentration, the nature of the material being disinfected, and how easily the disinfectant will come into contact with the microbes. The major effects of disinfection are disruption of plasma membranes, protein/enzyme denaturation, alteration of cellular components, lipid dissolution, and metabolic inhibition. Remember, most disinfectants only slow the growth of microbes. They are not as effective at killing microbes as most physical methods!

_____ = Minutes to kill 90% of a population at a given temperature

Decimal reduction time (DRT)

Microbial terminology

Degerming: the mechanical removal of microbes from a limited area Sanitization: lowering microbial counts on eating utensils to safe levels Biocide (germicide): treatments that kill microbes Bacteriostasis: inhibiting, not killing, microbes Sterilization: removing and destroying all microbial life Commercial sterilization: killing C. botulinum endospores from canned goods Disinfection: destroying harmful microorganisms Antisepsis: destroying harmful microorganisms from living tissue

_____ is removing water/drying stuff out

Desiccation

_____ is the absence of water (prevents metabolism)

Desiccation

Method that utilizes the zone of inhibition?

Disk-diffusion method

What method is used for heat sensitive materials?

Filtration High-efficiency particulate air (HEPA) filters remove microbes

One alternative to autoclaving for sterilization of liquids is filtration. Imagine that you are using a filter to sterilize a drug solution. You use a filter with a 0.22 μm pore size. Which of the following microbes will effectively be removed by this filter?

Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side. Nonionizing radiation, such as UV light, has a wavelength longer than that of ionizing radiation. The wavelengths of UV light are absorbed by cellular DNA in organisms directly exposed to the light. Desiccation is a process that removes water from microorganisms, leaving them unable to grow or reproduce, but still viable. Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food.

What kind of aldehyde is the most useful?

Glutaraldehyde

H2O2 is _____, used for

Hydrogen peroxide; antiseptic stuff

Very dangerous and powerful form of radiation, _____

IONIZING RADIATION Has enough energy to ionize water, split it up creating very powerful bad hydroxyl radicals

_____ is better at killing stuff than alcohol.

Iodine

Iodine combined with something other than alcohol, like something organic is called _____

Iodophor

Gamma and X-rays are what kind of radiation?

Ionizing

Is ionizing or nonionizing radiation more dangerous?

Ionizing

_____ is freeze drying

Lyophilization

Type of filter used for liquids?

Membrane filters

_____ kill by heat not radiation; are not especially antimicrobial

Microwaves

_____ heat denatures proteins. Examples are boiling or free-flowing steam

Moist

Moist heat vs. dry heat, which is faster?

Moist -> 15 minutes Dry -> 10 hours Why? More energy

_____ & _____ prevent spoilage of cheese

Nisin and natamycin

_____ & _____ prevent endospore germination

Nitrites & nitrates

_____ - you need a small amount to get a big effect

Oligodynamic action

_____ reduces spoilage organisms and pathogens

Pasteurization *REDUCED not sterilized

What kind of chemical... -Injures lipids of plasma membranes, causing leakage -First used as antiseptic by Lister

Phenol and Phenolics

Is radiation a physical method or chemical method of microbial control?

Physical The media's got us thinking wrong

WASH YOUR HANDS

Please

_____ is used to prevent ophthalmia neonatorum

Silver nitrate (stains skin red, goes away. All babies get this whose mothers did a natural birth, to prevent certain microbes from causing blindness)

Peroxygens and other forms of oxygen/oxidizing agents are not always effective, why?

Some organisms produce an enzyme called catalase that will turn hydrogen peroxide into water (S. aureus)

Wavelength of UV is most bactericidal (DNA absorbs)

Tanning beds kill flora!

Actions of microbial control agents

Target cell membrane (make it leaky) Damage to proteins (enzymes) Damage to nucleic acids

_____ are used to indicate sterility in moist heat

Test strips

_____ = lowest temperature at which all cells in a liquid culture are killed in 10 min

Thermal death point (TDP)

Yoou totally don't know this..

Thermal death point (TDP): lowest temperature at which all cells in a liquid culture are killed in 10 min Thermal death time (TDT): minimal time for all bacteria in a liquid culture to be killed at a particular temperature Decimal reduction time (DRT) Minutes to kill 90% of a population at a given temperature

_____ = minimal time for all bacteria in a liquid culture to be killed at a particular temperature

Thermal death time (TDT)

_____ organisms survive high temps/processes like Pasteurization

Thermoduric

Iodine combined with alcohol is

Tincuture

_____ is a special type of Pasteurization that has been sterilized

Ultra-high-temperature (UHT)

The greatest lesson from this microbiology class

Wash your hands, wash your fruit, wash it all

The absence of significant contamination

asepsis

_____ = steam under pressure

autoclave

Inhibits but doesn't kill _____

bacteriostasis

Treatments that kill microbes are called _____

biocide/germicide

_____ the removal of microbes from a limited area (i.e. with soap)

degerming

Soap

degerming; emulsification That is all

Ethylene oxide is a _____

gas (chemical sterilization)

Ethylene oxide is used for anything that is _____

heat sensitive (chemical sterilization)

As wavelength decreases, energy _____

increases (inversely related)

Nonionizing is also bad but does not have enough energy to _____

ionize water

Osmotic pressure uses salts and sugars to create a hypertonic environment, which causes

plasmolysis

Aldehydes are used for _____

preserving -toxic for us to breathe -Glutaraldehyde is one of the few liquid chemical sterilizing agents (safer, works better than formaldehyde)

Lowering microbial counts on eating utensils to safe levels is called _____

sanitization

Bacterial contamination

sepsis

Bisphenol

sounds like a chemical

Autoclave is a _____ process

sterilization

Removing or killing all microbial life is called

sterilization

Nonionizing radiation creates

thymine dimers

Alcohols (like ethanol and isopropanol) require _____ to work best

water (70% alcohol is most effective)