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An antibacterial agent is considered static if it ___________________
An antibacterial agent is considered static if it doesn’t kill the bacteria, but stops their growth completely
. Which of the following statements is true regarding the spores of Clostridium botulinum?
a. boiling water is cidal after about 9 hours
b. water at 1210 C is cidal after 5 minutes
c. water at 1160 C is cidal after 15 minutes
d. both a and b are correct
e. both a and c are correct
a. boiling water is cidal after about 9 hours
According to the idea of exponential death phase, if we had a sample containing 30,000
bacteria, and we autoclaved it for 15 minutes, how many bacteria would be alive at the 4 minute
time?
300
Which of the above characteristics apply to Free Flowing Steam ?
1. Sterilizes 2. Disinfects 3. Protein coagulation 4. Protein oxidation 5. Removes water necessary for enzymatic hydrolysis 6. Destroys only vegetative cells 7. Destroys spores
Free flowing steam:
2 disinfects
3 protein coagulation
6 destroys only vegetative cells
Which of the above characteristics apply to hot air oven?
1. Sterilizes 2. Disinfects 3. Protein coagulation 4. Protein oxidation 5. Removes water necessary for enzymatic hydrolysis 6. Destroys only vegetative cells 7. Destroys spores
hot air oven: 1 sterilizes 3 protein coagulation 4 protein oxidation 5 removes water necessary for enzymatic hydrolysis 7 destroys spores
What is the physical method for controlling bacteria is used prior to filtration in water purification?
sedimentation
What is the physical method for destroying bacteria is used primarily in research labs for studying internal
components of bacterial cells?
sonic vibrations
Which of the following pairs are mismatched?
a. syphilis - destroyed in minutes upon exposure to drying
b. tetanus spores - last indefinitely in dry conditions
c. gonorrhea- destroyed in an hour or so upon exposure to drying
d. Hepatitis B - destroyed quickly upon exposure to drying
e. HIV - destroyed quickly upon exposure to drying
d. Hepatitis B - destroyed quickly upon exposure to drying
Hepatitis B will last at least 7 days on a dry surface before being destroyed
Some drugs such as antibiotics are stored in a dry condition for preservation. The mode of
action of bacterial control with this method is ___________
removal of water necessary for enzymatic hydrolysis
Sunlight can be quite effective in killing bacteria. Mycobacterium can be killed in a few hours if
exposed. Currently it is thought that the mode of action of this process is ___________
protein oxidation
Which of the following is NOT TRUE regarding the use of ultraviolet radiation for control of
bacterial growth?
a. it is nonionizing radiation
b. it has a low power of penetration
c. it will cause thymine to bond to another thymine resulting in a mutation
d. it is used for air disinfection in laminar flow hoods
e. the high intensity of light causes photo oxidation
e. the high intensity of light causes photo oxidation
The correct mode of action of UV light is DNA forms pyrimidine dimers which leads to mutation
All of the following statements regarding cold temperatures are true EXCEPT
a. cold temperatures are not usually cidal to bacteria
b. refrigerator temperatures are primarily inhibitory to bacterial growth
c. freezer temperatures are primarily static to bacterial growth
d. the mode of action for freezing is removal of water for enzymatic hydrolysis
e. the mode of action of refrigeration is protein coagulation
e. the mode of action of refrigeration is protein coagulation
Refrigeration is inhibitory, it slows the rate of enzymatic reaction. This slows bacterial growth
All of the following produce hyperactive ions EXCEPT:
a. gamma rays
b. x-rays
c. microwaves
d. cathode rays
e. both c and d are incorrect
c. microwaves
microwaves are too low energy to produce hyperactive ions
Jams and jellies have 50 to 60% sugar concentrations. Therefore, the main reason most bacteria
do not grow in these foods is that their mode of action is _____________
plasmolysis of cells
What is the difference between plasmolysis and plasmoptysis of cells?
Plasmolysis is when a cell shrinks due to water living.
Plasmoptysis is the bursting fourth of protoplasm from a cell, through rupture of the cell wall.
for protein coagulation as a mode of action in chemical methods of control, True or false:
they disrupt the 3-D structure of proteins
true
for protein coagulation as a mode of action in chemical methods of control, True or false:
they stop enzymatic metabolism
true
for protein coagulation as a mode of action in chemical methods of control, True or false:
they are generally cidal
true
for protein coagulation as a mode of action in chemical methods of control, True or false:
they are generally narrow spectrum
false
for protein coagulation as a mode of action in chemical methods of control, True or false:
they cannot generally be used systemically
true
True or false:
chlorhexidene is a phenol derivative
false
True or false:
the mode of action of chlorhexidene is protein coagulation
true
True or false:
chlorhexidene is used for hand scrubbing and preparing sites for surgery
true
True or false:
chlorhexidene is safe since it is not absorbed into the deeper tissues of the skin
true
regarding phenol and its derivatives, true or false:
they remain effective in the presence of organic matter
true
regarding phenol and its derivatives, true or false:
they have analgesic properties
true
regarding phenol and its derivatives, true or false:
they are broad spectrum
true
regarding phenol and its derivatives, true or false:
they are protoplasmic poisons
true
regarding phenol and its derivatives, true or false:
they are useful for systemic control of organisms
false
Halazone was used commonly by campers to disinfect water from streams until it was found to
be ineffective against ____________.
protozoan cysts
The mode of action of halazone is considered to be _______________
protein oxidation
This agent is considered to be a mild oxidizing agent useful for disinfection of deep wounds
3% hydrogen peroxide
Many chemicals are said to be useful as “cold sterilants” but are really only disinfectants. Of the
agents listed below, which one actually sterilizes?
a. 3% hydrogen peroxide
b. 70% ethanol
c. 70% isopropanol
d. betadine
e. ethylene oxide
e. ethylene oxide
Which of the following statements are NOT TRUE concerning chemicals that disrupt lipoprotein membranes? a. they are surfactants b. they are generally cidal in action c. they are selectively toxic d. they can't be used systemically e. a, b and c are incorrect
c. they are selectively toxic
since both humans and bacteria have lipoprotein membranes, chemicals which disrupt them are harmful to both us and bacteria making them non selective
This agent is a nonionic detergent that is used in mouthwashes to control bacteria
a. sodium lauryl sulfate
b. cetylpyridinium chloride
c. benzalkonium chloride
d. bile
e. none of the above
e. none of the above
Taxo P discs are used in microbiology to help identify Streptococcus pneumoniae. They inhibit
the growth of this organism because they contain this anionic detergent
bile
This cyclical peptide antibiotic is isolated from Bacillus species and is used in selective media
such as Thayer Martin Selective agar
polymyxin E
This imidazole compound is a drug of choice that is used topically for dermatophytic infections
such as athlete’s foot
clotrimazole
This polyene antibiotic is isolated from Streptomyces species and is a main drug of choice for
systemic mycoses
amphotericin B
This antibiotic is used for severe cases of tuberculosis
streptomycin
This antibiotic is effective against many Rickettsial diseases
tetracycline
This antibiotic was used for meningitis caused by Haemophilus influenzae but is now considered
an alternate for that disease because of its toxicity
chloramphenicol
True or False? Halogens are effective antiseptics due to their mode of
action, which is disruption of cell membranes
False
During which part of the growth phase are cells more susceptible
to bacterial agents because the cells are sitting in their own toxic wastes
log death
True or False? Chemical agents such as chlorine may become inactivated
in solutions due to adsorption on to large particles known as colloids
suspended in the solution
true
Steam under pressure (15lbs/in2) is an effective means of sterilization
since the pressure allows the temperature to reach _________ °C
121.5 °C
High vacuum sterilization is a much quicker method of sterilization
simply because it uses a higher pressure allowing the temperature to
reach __________ °C
135 °C
The batch method of pasteurization is currently set at 62.9 °C to kill
Coxiella burnetii. Previously it was set a little lower to kill this pathogen
(give genus and species)
mycobacterium bovis
This protein coagulant is an acid that is commonly used as a
preservative in soft drinks and mouthwashes
benzoic acid
This heavy metal salt was commonly used in the eyes of newborns
to prevent infections picked up as the baby passed through the birth
canal
silver nitrate
This alcohol is used as a preservative in external preparations
benzyl
Dimorphic fungi can cause systemic mycoses. They are called
dimorphic because they look like yeast in the body but look like
molds when incubated at this temperature?
25 °C
True or False? Mouthwashes containing sodium lauryl sulfate should
generally be expected to be more effective than those containing
cetylpyridinium chloride
False
Give the mode of action and use for each of the following antibiotics:
Dapsone
Trimethoprim
Neomycin
dapsone- antimetabloite. leprosy
trimethroprim- antimetabloite. pneumocystis carinii pneumoniae
neomycin- protein synthesis. topical creams
Give four major uses for the antibiotic erythromycin, giving the genus and species of each specific organism and the name of the disease
ophthalmic neonatorum. Neisseria gonorrhoeae.
legionnaire’s disease. Legionella pneumophila
diphtheria. Corynebacterium diphtheriae
pertusis. bordetella pertusis
Give two drugs for as antivirals including the specific uses of each of these drugs
acyclovir- herpes viruses
azidothymidine- AIDS (HIV)
Give the specific uses of each of the following drugs:
Griseofulvin
Flucytosine
griseofulvin- dermatophytes
flucytosine- systemic mycoses
Describe the Flash method of pasteurization of milk, giving the time and temperature needed
71.6 °C for 15 seconds
Explain how infra-red light can be used for disinfection. That is, what is its mode of action?
absorbed as heat. dehydration, protein oxidation, protein coagulation
Explain the mode of action of antimetabolites, using PABA (paraaminobenzoic acid) as an example, stating the specific substrate, antimetabolite, and product
sulfa drugs trimethoprim
PABA (substrate)—x——-dihydrofolic acid—-x——–tetrahydrofolic acid—-purines,
pyrimidines, amino
acids
Define or describe these terms:
bactericide
MIC
bactericide-destroys bacteria except endospores
MIC- smallest concentration that visibly inhibits growth
Describe the use of the following agents:
quinine
metronidazole
mebendazole
quinine- antimalarial
metronidazole- amebic dysentery
mebendazole- melminths
Explain, using a graph, the effectiveness of number of hand scrubs, using a nongermicidal soap, in a 15 minute period in reducing the load of bacteria on hands
number of bacteria decrease with each washing. Effective in reducing load each 15 minutes, but
no residual action
Which of the following is/are a lactasmase resistant penicillin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(I) oxacillin is a lactasmase resistant penicillin
Which of the following is/are a repository penicillin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(H) benzathine penicillin is a repository penicillin
Which of the following is/are a natural penicillin resistant to acid in stomach: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(E) phenoxymethyl penicillin is a natural penicillin resistant to acid in stomach
Which of the following is/are a broad spectrum penicillin used for UTI's caused by pseudomonas aeruginosa: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(C) carbenicillin is a broad spectrum penicillin used for UTI’s caused by pseudomonas aeruginosa
Which of the following is/are a third generation cephalosporin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(L) moxalactam is a third generation cephalosporin
Which of the following is/are a penicillin with an extra amino group effective against UTI's caused by Proteus mirabilis: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(G) ampicillin is a penicillin with an extra amino group effective against UTI’s caused by Proteus mirabilis
Which of the following is/are used for MRSA: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(N) vancomycin is used for MRSA
Which of the following is/are a polypeptide antibiotic effective against G+ bacteria: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(M) bacitracin is a polypeptide antibiotic effective against G+ bacteria
Which of the following has protein coagulation as a mode of action and is used as an antiseptic and analgesic on mucous membranes : A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(A) cresyl acetate has protein coagulation as a mode of action and is used as an antiseptic and analgesic on mucous membranes
Which of the following is/are an organic form of mercury and a skin antiseptic: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin
(F) thimerosal is an organic form of mercury and a skin antiseptic
