Portage Learning: Microbiology Module
5
Universal precautions means any and all samples, whether known or unknown, are to
be treated as potentially hazardous (or pathogenic) materials.
Define the concept of universal precautions.
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
4. The presence of any chemical reactions
5. Changes in color localized to the organism or the surrounding media
6. Capture (or draw) images of any of the characteristics described above
What would a researcher be certain to note while analyzing a microbial sample?
A BAP (blood agar plate) would be the quickest way to identify and classify a potential
streptococcus microbe based on its hemolytic properties.
Which non-selective yet differential agar plate should be used if a Streptococcus sample
is suspected?
Rheumatic fever occurs in approximately 3% of untreated cases of streptococcal
pharyngitis, presenting approximately 2-3 weeks post-infection.
What disease can result if a patient with streptococcal pharyngitis goes untreated?
All of the above foreign microbes are capable of causing septicemia, also known as
blood poisoning.
Streptococcus, E. coli, pseudomonas, and klebsiella are all capable of causing what
disease?
,A facultative anaerobe is capable of growth under both aerobic (with oxygen) and
anaerobic (in the absence of oxygen) condition.
What is a facultative anaerobe?
Staphylococcus species are capable of growth in the presence of bile salts.
How can Staphylococcus be differentially tested?
The causative agent of impetigo is staph aureus, a Gram-positive bacterium capable of
fermenting mannitol. Fermentation will lower the pH of the agar and change the dye
color from red to yellow.
A bacterial swab is taken from a patient with impetigo and streaked across an MSA
plate. Following incubation at 37C, what will be the color of the agar?
To stain for TB, one would utilize an acid-fast stain to best visual the foreign microbe.
As a mycobacterium tuberculosis would stain poorly (indeterminate) using the Gram
stain.
If a patient were suspected to have tuberculosis (TB), which differential stain would you
select and why?
Leprosy is completely curable using a multiple-drug therapy regimen consisting of
various combinations of the drugs dapsone, rifampin and clofazimine—all of which is
given free of charge.
According to the module, which mycobacterium infection will be treated free of charge
by the World Health Organization (WHO)?
Foodborne, infant and wound. Foodborne botulism is often the result of improperly
canned, contaminated, low-acidic foods such as green beans, corn and beats. Infant
botulism occurs when children, usually under the age of 6 months consume foods
containing the bacteria. A potential source of infant botulism is honey (which is why
pediatricians recommend avoiding feeding honey to infants) but can also be found in
, common places such as soil. Wound botulism occurs when C. botulinum bacteria
colonize a deep wound, often a puncture such as those who inject street drugs such as
heroine. As contaminated needles are injected through the skin, spores enter the body
and, in the absence of oxygen, release the toxin.
What are the three main conditions caused by the botulism toxin?
Due to infants still maturing intestinal tract and lack of an adult microbiota, the bacteria
are able to colonize and produce the associated toxin. In adults, only the direct
ingestion of the pre-formed toxin causes disease—ingestion of C. botulinum or the
associated spores do not cause illness as a mature intestinal microbiota sufficiently
prevents bacterial germination and growth.
Why are infants (< 6 months) more susceptible to botulism?
The toxin acts on inhibitory neurons causing systemic muscle stiffness and spasms.
Muscle stiffness can be observed in the jaw (lock-jaw) or spread systemically (if left
untreated) to muscles relating to respiratory function.
What is the mechanism of action of the toxin produced by clostridium tentani (tetanus)?
Legionella is often associated with unclean water systems such as hot tubs, hot water
tanks and AC units. Notably, legionella can only be transmitted through water droplets
small enough to be inhaled.
What Gram-negative bacterium might you come into contact with in a unsanitary hot
tub?
Bubonic (lymph), pneumonic (lungs) and septicemic (blood). Bubonic plague is best
characterized by painfully swollen lymph nodes. Pneumonic plague affects the
respiratory system (lungs). The most rare of all three plagues, septicemic plague targets
the blood system and, if left untreated, will develop into a life-threatening illness as the
blood-borne bacteria can infect all major organs.
5
Universal precautions means any and all samples, whether known or unknown, are to
be treated as potentially hazardous (or pathogenic) materials.
Define the concept of universal precautions.
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
4. The presence of any chemical reactions
5. Changes in color localized to the organism or the surrounding media
6. Capture (or draw) images of any of the characteristics described above
What would a researcher be certain to note while analyzing a microbial sample?
A BAP (blood agar plate) would be the quickest way to identify and classify a potential
streptococcus microbe based on its hemolytic properties.
Which non-selective yet differential agar plate should be used if a Streptococcus sample
is suspected?
Rheumatic fever occurs in approximately 3% of untreated cases of streptococcal
pharyngitis, presenting approximately 2-3 weeks post-infection.
What disease can result if a patient with streptococcal pharyngitis goes untreated?
All of the above foreign microbes are capable of causing septicemia, also known as
blood poisoning.
Streptococcus, E. coli, pseudomonas, and klebsiella are all capable of causing what
disease?
,A facultative anaerobe is capable of growth under both aerobic (with oxygen) and
anaerobic (in the absence of oxygen) condition.
What is a facultative anaerobe?
Staphylococcus species are capable of growth in the presence of bile salts.
How can Staphylococcus be differentially tested?
The causative agent of impetigo is staph aureus, a Gram-positive bacterium capable of
fermenting mannitol. Fermentation will lower the pH of the agar and change the dye
color from red to yellow.
A bacterial swab is taken from a patient with impetigo and streaked across an MSA
plate. Following incubation at 37C, what will be the color of the agar?
To stain for TB, one would utilize an acid-fast stain to best visual the foreign microbe.
As a mycobacterium tuberculosis would stain poorly (indeterminate) using the Gram
stain.
If a patient were suspected to have tuberculosis (TB), which differential stain would you
select and why?
Leprosy is completely curable using a multiple-drug therapy regimen consisting of
various combinations of the drugs dapsone, rifampin and clofazimine—all of which is
given free of charge.
According to the module, which mycobacterium infection will be treated free of charge
by the World Health Organization (WHO)?
Foodborne, infant and wound. Foodborne botulism is often the result of improperly
canned, contaminated, low-acidic foods such as green beans, corn and beats. Infant
botulism occurs when children, usually under the age of 6 months consume foods
containing the bacteria. A potential source of infant botulism is honey (which is why
pediatricians recommend avoiding feeding honey to infants) but can also be found in
, common places such as soil. Wound botulism occurs when C. botulinum bacteria
colonize a deep wound, often a puncture such as those who inject street drugs such as
heroine. As contaminated needles are injected through the skin, spores enter the body
and, in the absence of oxygen, release the toxin.
What are the three main conditions caused by the botulism toxin?
Due to infants still maturing intestinal tract and lack of an adult microbiota, the bacteria
are able to colonize and produce the associated toxin. In adults, only the direct
ingestion of the pre-formed toxin causes disease—ingestion of C. botulinum or the
associated spores do not cause illness as a mature intestinal microbiota sufficiently
prevents bacterial germination and growth.
Why are infants (< 6 months) more susceptible to botulism?
The toxin acts on inhibitory neurons causing systemic muscle stiffness and spasms.
Muscle stiffness can be observed in the jaw (lock-jaw) or spread systemically (if left
untreated) to muscles relating to respiratory function.
What is the mechanism of action of the toxin produced by clostridium tentani (tetanus)?
Legionella is often associated with unclean water systems such as hot tubs, hot water
tanks and AC units. Notably, legionella can only be transmitted through water droplets
small enough to be inhaled.
What Gram-negative bacterium might you come into contact with in a unsanitary hot
tub?
Bubonic (lymph), pneumonic (lungs) and septicemic (blood). Bubonic plague is best
characterized by painfully swollen lymph nodes. Pneumonic plague affects the
respiratory system (lungs). The most rare of all three plagues, septicemic plague targets
the blood system and, if left untreated, will develop into a life-threatening illness as the
blood-borne bacteria can infect all major organs.
