Lecture 7 - Growth PART TWO Flashcards
in an obligate aerobe, where do the microbes stay in a broth tube?
they lay at the top, since the microbes really need oxygen.
do obligate aerobes create toxic waste products? if so, what do they do to get rid of it?
yes, they have enzymes in their cells for O2 detoxification.
in a facultative anaerobe, where do the microbes lay in a broth tube?
they stay everywhere in the tube, however since they prefer O2, there are some more microbes laying on the top next to the O2.
do facultative anaerobes create toxic waste products?
yes, they also have detoxifying enzymes.
in obligate anaerobes, where do the microbes lay?
they stay at the bottom of the broth tube, since they don’t like O2.
do obligate anaerobes create toxic waste products?
no
in microaerophiles, where do the microbes lay?
they lay close to the surface, but still leave a little space, since they like a little bit of O2.
do microaerophiles create toxic waste products?
yes, small amounts.
in aerotolerant organisms, where do the microbes lay in a broth tube?
they lay dispersed all over, since they can tolerate O2.
do aerotolerant organisms create toxic wast products?
yes
T/F: all microbes need energy and a carbon source - it just depends where the energy and carbon are sourced from.
True
what does an organic molecule consist of?
carbon and hydrogen
what are photoautotoph’s energy and carbon source?
-Solar (sun) energy source.
-CO2 (carbon dioxide) carbon source.
what are photoheterotroph’s energy and carbon source? what does the root hetero refer to?
-Solar energy source.
-Organic compounds carbon source (glucose, proteins).
Hetero = organic
what are chemolithoautotrophs energy and carbon source? what does the roots chemo and litho refer to?
-Inorganic compounds (H2, NH3) energy source.
-CO2 carbon source.
chemo = chemical.
litho = inorganic
what are chemoorganoheterotroph’s energy and carbon source? what does organo refer to?
-Organic compounds (sugars, amino acids) energy source.
-Organic compounds carbon souse.
Organo = organic
what components are needed for growth?
Major components (CHONPS) and trace elements
what category of the previous nutrients are humans in?
chemoorganoheterotrophs
what category of the previous nutrients are pathogens in?
chemoorganoheterotrophs
Describe an organism that:
-grows at body temperature
-thrives in acid
-can live with or without oxygen
-uses organic matter for both carbon and energy
-mesophile
-acidophile
-facultative anaerobe
-chemoorganoheterotrophs
what is the purpose of controlling microbe growth?
to reduce the chances of infections
what did Ignaz Semmelweis come up with?
After realizing doctors were infecting mothers from the bacteria from cadavers, Semmelweis prescribed “chlorine hand washing” to kill particles before operating on mothers - and it worked.
what do we now know was the name of the disease causing infection that killed mothers during childbirth?
Puerperal fever - infection of the uterus by Streptococcus pyogenes
what did Joseph Lister come up with?
he hypothesized that infected wounds would develop pus due to “minute organisms”. He started applying carbolic acid to wounds to kill these organisms and he saw that this practice prevented pus formation.
Joseph Lister also started doing what with disinfectant?
He started disinfecting surgical instruments and maintaining a clean operating room to prevent infections during surgery
T/F: Different risks call for different levels of control
true
when choosing microbial growth control methods, what are different things to consider?
-Type of organism
-Numbers present initially
-Organic matter/biofilms
-Time of exposure
-Risk of infection
-Composition of item
-Toxicity
-Cost and availability
from most resistant to kill to least resistant to kill (easiest to kill) what are different microbes?
Prions
Endospores of bacteria
Mycobacteria
Cysts of protozoa
Vegetative protozoa
Gram-negative bacteria
Fungi (inc. most fungal spores)
Viruses without envelopes
Gram-positive bacteria
Viruses with lipid envelopes
what is sterilization?
killing ALL vegetative cells, viruses, and endospores
what is vegetative?
growing and metabolically active cells
what is sterilization used for?
for surgical instruments
does sterilization kill endospores?
yes
what is disinfection?
kills MOST or all vegetative cells and viruses
does disinfection kill endospores?
no
what is a disinfectant?
used for non-living things; ex: lab bench
what is an antiseptic used for?
living things; ex: mouth wash
what is decontamination?
it reduces the number of pathogens to a safe level
what is an example of decontaminating?
washing hands
does decontamination get rid of all bacteria?
NO
is decontamination sterilizing as well?
NO
what is preservation?
the process of delaying the spoilage of perishable products
what are examples of preservation?
Refrigeration
Drying
Chemical Preservative
Pasteurization
what is pasteurization?
reducing the number of spoilage microbes and kills pathogens
what is an example of pasteurization?
milk (at 72 degrees for 15 sec)
does pasteurization get rid of all microbes?
NO
what type of temp. does pasteurization use?
HEAT
what are the suffixes and examples of words for destroying (killing) microbes?
-cidal
-cide
Germicide, Bactericide, Fungicide, Virucide
what are the suffixes and examples of words for inhibiting microbes?
-stasis
-static
Bacteriostatic, Fungistatic, Virustatic
what are 3 methods of using physical methods for killing microbes?
Heat (autoclave), Filtration, Radiation
what does heat do to microbes?
it denatures proteins and destroys cell components
is heat the #1 method?
yes, if available
what are two types of heat used?
- Dry heat: flaming (loop), incineration (medical waste/carcasses), dry heat ovens (glassware).
- Moist heat: boiling 5-10 minutes (for drinking water), pasteurization (milk, juices), autoclave (pressurized steam for surgical instruments and lab media).
what is the autoclave used for?
it is the preferred method of sterilization for surgical and medical equipment, media, glassware (if available)
what is the standard protocol for autoclaving?
121 degrees C at 15 psi for 15 minutes
what does this protocol for autoclaving destoy?
ENDOSPORES
out of the heat and pressure of the autoclave, what actually kills the microbes?
the heat.
does autoclaving destroy endospores?
yes
what is filtration?
it filters out microbes
what are examples of filtration?
-Liquid (membrane filters) - beer, wine, medications
-Air (HEPA filters) - biosafety cabinets, airplanes
what type of things use filtration?
heat sensitive things
can you autoclave antibiotics?
NO
how does the filtration actually work?
the bacteria are bigger than the filter pores, so they will be stuck and not go through
what does radiation damage?
it damages DNA
what are the two examples of radiation?
- Ionizing radiation (gamma and x-rays): spices, meats, drugs, disposable surgical supplies (forms ions).
- Non-ionizing radiation (UV light): drinking water, surfaces (doesn’t form ions).
can UV lights penetrate into an object and sterilize it?
no, just the surface
are microwaves considered forms of radiation that sterilize?
NO, they generate heat that kills microbes but does not heat evenly. It doesn’t destroy all bacteria, so don’t cook raw meat in a microwave.
various chemicals can sterilize, what does the chemicals do?
Chemicals disrupt cell membranes, proteins, or nucleis acids
what are examples of liquid and gases of chemicals?
Liquids: Lysol, bleach
Gases: Ethylene oxide, ozone
what concerns do we have about chemicals?
we have concerns about overuse and resistance because microbes can develop resistance to these chemicals
what does alcohol do?
denatures proteins and destroys membranes
what are the benefits of alcohol?
cheap, non-toxic, and evaporates quickly
what do Aldehydes do?
they inactivate proteins and nucleic acids
can aldehydes destroy endospores?
yes, if they are treated for 10-12 hours
are some Aldehydes toxic?
yes
what is an example of biguanides?
Chlorhexdine
where are biguanides found?
in skin creams, mouthwashes, cathaders
how toxic are biguanides?
low-toxicity
what are examples of halogens?
chlorine and iodine
can chlorine destroy endospores?
yes it can
can a high-bleach content be sterilizing?
yes
is chlorine toxic?
yes
what do metal compounds do?
destroy proteins by reacting with -SH groups
are metal compounds toxic?
yes
what are quats?
Quaternary ammonium compounds; cationic detergents (positively charged cations kill bacteria)
what do quats do?
destroy membrane
where are quats found?
shampoos and facial cleansers
what are the pro’s of quats?
cheap and effective
what do peroxygens do?
they oxidize biomolecules
what are peroxygens used to sterilize?
containers to package milk, etc.
the peroxygen hydrogen peroxide, is what…?
a biproduct of O2
what do phenolics do?
denature proteins and destroy membranes
what is Ethylene oxide?
it is a gas
what is Ethylene oxide used for?
for sterilization of heat and moisture sensitive stuff
where is Ethylene oxide used?
pacemakers, artificial hip, pillows
what are the cons of Ethylene oxide?
explosive and toxic
what does ozone do? where is it used? what are the cons?
-Sterilization
-Pacemakers, artificial hip, pillows
-Explosive and toxic
which bacteria is easier to destroy?
-Naked viruses
-Enveloped viruses
-Enveloped viruses because of the phospholipid bilayer. It is easier to destroy with alcohol.
what bacteria is easier to destroy/kill?
-Gram-negative
-Gram-positive
Gram-negative because of the outer membrane
if your goal is to sterilize an IV bag of fluids containing glucose (which caramelizes at high temperatures), what is the best way to do so?
Filtration
A chemoorganoheterotroph gets energy from _____ and carbon from _____.
organic matter; organic matter
To sterilize an object using an autoclave, one standard protocol is:
121 C at 15 psi for 15 minutes
