Portage Microbiology Exam #5
Define the concept of universal precautions (short answer) - Answer Universal
precautions means any and all samples, whether known or unknown, are to be treated
as potentially hazardous (or pathogenic) materials
List at lease 3 observations a researcher would be sure to note while assessing and
unknown microbial sample (short answer) - Answer Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
While observing an unknown sample of limited amounts, a researcher must determine
the following observations: 1) the presence of any motility and 2) its Gram status using
the same sample- the liquid sample cannot be divided. Which would you determine first
and why? (short answer) - Answer You must determine motility before determining
Gram status. Motility requires a wet mount, while gram staining requires heat fixing the
sample. If one were to begin with the gram stain, the heat fixation process would kill the
organism, making any observations regarding motility impossible. The correct approach
would be to place the liquid culture on a glass slide and determine its motility status.
Next, the same liquid culture can be heat fixed and gram stained.
A facultative anaerobe is a microorganism capable of growth under what conditions?
(short answer) - Answer A facultative anaerobe is capable of growth under aerobic (with
oxygen) and anaerobic (without oxygen) conditions
True or False: The Lancefield groups are used to subdivide antigenic groups of alpha-
hemolytic Streptococcus - Answer False. The Lancefield groups are used to subdivide
beta-hemolytic strep
The distinctions for Lancefield subgroups lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above - Answer B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left
untreated - Answer Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of
human population where it remains non-symptomatic - Answer False. Staphylococcus
in only found (non-symptomatic) in ~30% of the human population
Define commensal bacteria (short answer) (know term and definition first) - Answer The
bacterium neither harms nor benefits from the host from which it obtains nutrients
, How can staphylococcus be differentially tested? (short answer) - Answer
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - Answer Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - Answer Ruptured-pustules; treated with penicilin
Symptoms of Impetigo - Answer Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - Answer Infections of thin, transparent scieral tissue
Symptoms of ophthalmia neonatorum - Answer Infection occurs at time of birth
True or False: the causative agent of conjunctivitis can be either bacterial or viral -
Answer True. There are bacterial (staph) and viral forms of conjunctivitis, both resulting
in the inflammation of the conjunctiva and 'pink eye'
True or False: Tuberculosis is best identified by a gram stain - Answer False.
Mycobacterium show poor Gram staining and show be screened via an acid-fast stain
True or False: You can become infected with TB simply by sharing a drink with
someone who is currently infected with TB - Answer False. As per the CDC guidelines,
simply shaking someone's hand, sharing a drink, or even kissing someone cannot
spread TB
Identify the disease based on the following (select all that apply): It is a small, acid-fast
rod usually remaining asymptomatic for up to 20 years. It affects the skin, nerves, upper
respiratory tract and eyes of infected individuals
A. Tuberculosis
B. Leprosy
C. Scalded-skin syndrome
D. Hansen's disease
E. Bacterial conjunctivitis - Answer B & D (Hansen's disease is another name for
leprosy)
True or False: Only directly ingesting the pre-formed clostridium toxin (neither the
bacteria nor its spores) will cause disease in adults - Answer True
While visiting his grandparents, a 10-year old child has green beans for dinner that were
harvested from his grandparents' garden and canned the previous year. Severe illness
sets in and the child is taken to the hospital. Botulism is suspected, but what form?
(short answer) - Answer Foodbourne botulism. The child is too old (> 6 months) to be
considered and wounds were not present. The green beans were likely improperly
canned and under the low-acidic, anaerobic conditions, bacterial growth was
encouraged
Define the concept of universal precautions (short answer) - Answer Universal
precautions means any and all samples, whether known or unknown, are to be treated
as potentially hazardous (or pathogenic) materials
List at lease 3 observations a researcher would be sure to note while assessing and
unknown microbial sample (short answer) - Answer Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
While observing an unknown sample of limited amounts, a researcher must determine
the following observations: 1) the presence of any motility and 2) its Gram status using
the same sample- the liquid sample cannot be divided. Which would you determine first
and why? (short answer) - Answer You must determine motility before determining
Gram status. Motility requires a wet mount, while gram staining requires heat fixing the
sample. If one were to begin with the gram stain, the heat fixation process would kill the
organism, making any observations regarding motility impossible. The correct approach
would be to place the liquid culture on a glass slide and determine its motility status.
Next, the same liquid culture can be heat fixed and gram stained.
A facultative anaerobe is a microorganism capable of growth under what conditions?
(short answer) - Answer A facultative anaerobe is capable of growth under aerobic (with
oxygen) and anaerobic (without oxygen) conditions
True or False: The Lancefield groups are used to subdivide antigenic groups of alpha-
hemolytic Streptococcus - Answer False. The Lancefield groups are used to subdivide
beta-hemolytic strep
The distinctions for Lancefield subgroups lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above - Answer B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left
untreated - Answer Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of
human population where it remains non-symptomatic - Answer False. Staphylococcus
in only found (non-symptomatic) in ~30% of the human population
Define commensal bacteria (short answer) (know term and definition first) - Answer The
bacterium neither harms nor benefits from the host from which it obtains nutrients
, How can staphylococcus be differentially tested? (short answer) - Answer
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - Answer Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - Answer Ruptured-pustules; treated with penicilin
Symptoms of Impetigo - Answer Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - Answer Infections of thin, transparent scieral tissue
Symptoms of ophthalmia neonatorum - Answer Infection occurs at time of birth
True or False: the causative agent of conjunctivitis can be either bacterial or viral -
Answer True. There are bacterial (staph) and viral forms of conjunctivitis, both resulting
in the inflammation of the conjunctiva and 'pink eye'
True or False: Tuberculosis is best identified by a gram stain - Answer False.
Mycobacterium show poor Gram staining and show be screened via an acid-fast stain
True or False: You can become infected with TB simply by sharing a drink with
someone who is currently infected with TB - Answer False. As per the CDC guidelines,
simply shaking someone's hand, sharing a drink, or even kissing someone cannot
spread TB
Identify the disease based on the following (select all that apply): It is a small, acid-fast
rod usually remaining asymptomatic for up to 20 years. It affects the skin, nerves, upper
respiratory tract and eyes of infected individuals
A. Tuberculosis
B. Leprosy
C. Scalded-skin syndrome
D. Hansen's disease
E. Bacterial conjunctivitis - Answer B & D (Hansen's disease is another name for
leprosy)
True or False: Only directly ingesting the pre-formed clostridium toxin (neither the
bacteria nor its spores) will cause disease in adults - Answer True
While visiting his grandparents, a 10-year old child has green beans for dinner that were
harvested from his grandparents' garden and canned the previous year. Severe illness
sets in and the child is taken to the hospital. Botulism is suspected, but what form?
(short answer) - Answer Foodbourne botulism. The child is too old (> 6 months) to be
considered and wounds were not present. The green beans were likely improperly
canned and under the low-acidic, anaerobic conditions, bacterial growth was
encouraged
