Universal precautions means any and
Define the concept of universal precau- all samples, whether known or unknown,
tions. are to be treated as potentially haz-
ardous (or pathogenic) materials.
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
What would a researcher be certain to 4. The presence of any chemical reac-
note while analyzing a microbial sam- tions
ple? 5. Changes in color localized to the or-
ganism or the surrounding media
6. Capture (or draw) images of any of the
characteristics described above
A BAP (blood agar plate) would be the
Which non-selective yet differential agar
quickest way to identify and classify a
plate should be used if a Streptococcus
potential streptococcus microbe based
sample is suspected?
on its hemolytic properties.
Rheumatic fever occurs in approximate-
What disease can result if a patient with
ly 3% of untreated cases of streptococ-
streptococcal pharyngitis goes untreat-
cal pharyngitis, presenting approximate-
ed?
ly 2-3 weeks post-infection.
Streptococcus, E. coli, pseudomonas, All of the above foreign microbes are ca-
and klebsiella are all capable of causing pable of causing septicemia, also known
what disease? as blood poisoning.
A facultative anaerobe is capable of
growth under both aerobic (with oxygen)
What is a facultative anaerobe?
and anaerobic (in the absence of oxy-
gen) condition.
How can Staphylococcus be differential- Staphylococcus species are capable of
ly tested? growth in the presence of bile salts.
The causative agent of impetigo is staph
A bacterial swab is taken from a patient
aureus, a Gram-positive bacterium capa-
with impetigo and streaked across an
ble of fermenting mannitol. Fermentation
MSA plate. Following incubation at 37C,
will lower the pH of the agar and change
what will be the color of the agar?
the dye color from red to yellow.
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, Portage Learning Microbiology BIOD 171 module 5 Questions and Answers
To stain for TB, one would utilize an
If a patient were suspected to have tu- acid-fast stain to best visual the foreign
berculosis (TB), which differential stain microbe. As a mycobacterium tubercu-
would you select and why? losis would stain poorly (indeterminate)
using the Gram stain.
Leprosy is completely curable using a
According to the module, which my-
multiple-drug therapy regimen consist-
cobacterium infection will be treated free
ing of various combinations of the drugs
of charge by the World Health Organiza-
dapsone, rifampin and clofazimine—all
tion (WHO)?
of which is given free of charge.
Foodborne, infant and wound. Food-
borne 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 bot-
ulism is honey (which is why pediatri-
What are the three main conditions
cians recommend avoiding feeding hon-
caused by the botulism toxin?
ey to infants) but can also be found in
common places such as soil. Wound bot-
ulism occurs when C. botulinum bacteria
colonize a deep wound, often a puncture
such as those who inject street drugs
such as heroine. As contaminated nee-
dles are injected through the skin, spores
enter the body and, in the absence of
oxygen, release the toxin.
Due to infants still maturing intestinal
tract and lack of an adult microbiota, the
bacteria are able to colonize and pro-
Why are infants (< 6 months) more sus- duce the associated toxin. In adults, only
ceptible to botulism? 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
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