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MMSC 428 Exam 4 Questions with Detailed
Verified Answers
Question: Anaerobes
Ans✅ ✅: 1. Are able to replicate in the absence of oxygen.
2. Anaerobic cultures performed in clinical microbiology laboratories are used to
recover organisms in these two groups.
Question: Obligate Anaerobes
Ans✅ ✅: 1. Unable to grow in the presence of oxygen (oxygen is toxic). Also called
"strict" anaerobes.
Question: Aerotolerant Anaerobes
Ans✅ ✅: 1. Able to survive short exposures to oxygen, but unable to perform many
metabolic processes in the presence of oxygen. Also called "moderate" anaerobes
Question: Endogenous Anaerobes
Ans✅ ✅: 1. Opportunistic pathogens, usually gaining access to tissues, sterile body
sites, and the bloodstream.
Question: Anaerobes: Normal Microbiota
Ans✅ ✅: 1. Many different sites
2. Skin, upper respiratory tract, oral cavity, GI tract, and genitourinary tract.
Question: Anaerobes: Incidence of Infection
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Ans✅ ✅: 1. Infections may be localized to the colonizing site, adjacent to the site, or
distant from the colonizing site.
2. Bacteremia
3. Variety of abscesses (brain, lungs, oral, abdomen, etc)
4. Peritonitis
5. Female genital infections
6. Myonecrosis
7. Aspiration pneumonia
Question: T/F: Many infections involving anaerobes are polymicrobial:
consisting of mixtures of anaerobes, or anaerobes and aerobes.
Ans✅ ✅: True
Question: Anaerobic Infections: Clues for ID
Ans✅ ✅: 1. Presence of foul odor
2. Infection in close proximity to a mucosal surface
3. Infection following human or animal bites
4. Traumatic puncture of the bowel or genital tract (following trauma or surgery)
5. Necrotic tissue, gangrene
6. Large quantity of gas
Question: Anaerobes: Collection of Specimens
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Ans✅ ✅: 1. Suitable specimens
- All sites not likely to be contaminated with normal microbiota can be cultured for
anaerobes
2. Unsuitable specimens
- Sites that are likely contaminated by normal microbiota
Question: Anaerobes: Suitable Specimens
Ans✅ ✅: 1. Sterile body fluids/aspirates, blood & bone marrow, tissues & bones,
aspirated closed abscesses
Question: Anaerobes: Unsuitable Specimens
Ans✅ ✅: 1. URT and oral swabs, sputum/BAL, stool/bowel contents/rectal swabs,
voided urine, genital swabs, surface swabs from wounds, any material collected
adjacent to a mucous membrane where adequate decontamination was not performed
Question: Anaerobes: Collection w/ Aspirates & Tissues
Ans✅ ✅: 1. Aspirates of fluids/purulent material collected by needle and syringe are
the specimens of choice over swabs as they are less likely to be contaminated by
endogenous microbiota and provide more material than swabs.
2. Tissues collected by biopsy and bones are also ideal specimens. Swabs are the least
ideal collection method and should only be used when aspiration is not possible or
tissue cannot be obtained.
Question: Anaerobes: Transport
Ans✅ ✅: 1. Provides oxygen-free environment to protect obligate anaerobes.
2. Preservative-free vacuum collection tubes can be used for fluids. Sterile cup can be
used for larger tissues (>1 cm2) provided they are transported to the lab within a few
hours. All specimens should be transported ASAP and maintained at Room
temperature.
Question: Anaerobes: Direct Exam
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Ans✅ ✅: 1. Gram stains should be performed on all non-blood specimens submitted
for anaerobic culture for several reasons
2. The presence of multiple distinct organism morphotypes suggests that the infection
is polymicrobic.
3. Certain morphotypes may provide a presumptive identification of the causative
organisms. E.g. Large, boxcar-like GPB suggest Clostridium species. Thin, fusiform
GNB suggest Fusobacterium.
4. Gram stain helps evaluate the quality of the specimen based on the presence and
number of SECs, that would suggest specimen contamination during collection.
5. Helps to identify morphotypes that were seen in Gram stain but not recovered in
culture. Different culture media may be needed or anaerobic culture conditions were
not initially met.
-Detect toxins directly in the specimen (e.g. C. difficile toxins in stool)
Question: T/F: Anaerobes direct examination includes gross &
microscopic exams and detect toxins
Ans✅ ✅: True
Question: Anaerobes: Culture Characteristics
Ans✅ ✅: 1. Media
a) Nutritious primary isolation media: prereduced, room temperature
1) CDC anaerobic blood agar & Brucella agar
2) Laked sheep blood with vitamin K
3) Broths
a) Thioglycollate
b) Chopped (cooked) meat
Question: Who am I?
MMSC 428 Exam 4 Questions with Detailed
Verified Answers
Question: Anaerobes
Ans✅ ✅: 1. Are able to replicate in the absence of oxygen.
2. Anaerobic cultures performed in clinical microbiology laboratories are used to
recover organisms in these two groups.
Question: Obligate Anaerobes
Ans✅ ✅: 1. Unable to grow in the presence of oxygen (oxygen is toxic). Also called
"strict" anaerobes.
Question: Aerotolerant Anaerobes
Ans✅ ✅: 1. Able to survive short exposures to oxygen, but unable to perform many
metabolic processes in the presence of oxygen. Also called "moderate" anaerobes
Question: Endogenous Anaerobes
Ans✅ ✅: 1. Opportunistic pathogens, usually gaining access to tissues, sterile body
sites, and the bloodstream.
Question: Anaerobes: Normal Microbiota
Ans✅ ✅: 1. Many different sites
2. Skin, upper respiratory tract, oral cavity, GI tract, and genitourinary tract.
Question: Anaerobes: Incidence of Infection
, Page | 2
Ans✅ ✅: 1. Infections may be localized to the colonizing site, adjacent to the site, or
distant from the colonizing site.
2. Bacteremia
3. Variety of abscesses (brain, lungs, oral, abdomen, etc)
4. Peritonitis
5. Female genital infections
6. Myonecrosis
7. Aspiration pneumonia
Question: T/F: Many infections involving anaerobes are polymicrobial:
consisting of mixtures of anaerobes, or anaerobes and aerobes.
Ans✅ ✅: True
Question: Anaerobic Infections: Clues for ID
Ans✅ ✅: 1. Presence of foul odor
2. Infection in close proximity to a mucosal surface
3. Infection following human or animal bites
4. Traumatic puncture of the bowel or genital tract (following trauma or surgery)
5. Necrotic tissue, gangrene
6. Large quantity of gas
Question: Anaerobes: Collection of Specimens
, Page | 3
Ans✅ ✅: 1. Suitable specimens
- All sites not likely to be contaminated with normal microbiota can be cultured for
anaerobes
2. Unsuitable specimens
- Sites that are likely contaminated by normal microbiota
Question: Anaerobes: Suitable Specimens
Ans✅ ✅: 1. Sterile body fluids/aspirates, blood & bone marrow, tissues & bones,
aspirated closed abscesses
Question: Anaerobes: Unsuitable Specimens
Ans✅ ✅: 1. URT and oral swabs, sputum/BAL, stool/bowel contents/rectal swabs,
voided urine, genital swabs, surface swabs from wounds, any material collected
adjacent to a mucous membrane where adequate decontamination was not performed
Question: Anaerobes: Collection w/ Aspirates & Tissues
Ans✅ ✅: 1. Aspirates of fluids/purulent material collected by needle and syringe are
the specimens of choice over swabs as they are less likely to be contaminated by
endogenous microbiota and provide more material than swabs.
2. Tissues collected by biopsy and bones are also ideal specimens. Swabs are the least
ideal collection method and should only be used when aspiration is not possible or
tissue cannot be obtained.
Question: Anaerobes: Transport
Ans✅ ✅: 1. Provides oxygen-free environment to protect obligate anaerobes.
2. Preservative-free vacuum collection tubes can be used for fluids. Sterile cup can be
used for larger tissues (>1 cm2) provided they are transported to the lab within a few
hours. All specimens should be transported ASAP and maintained at Room
temperature.
Question: Anaerobes: Direct Exam
, Page | 4
Ans✅ ✅: 1. Gram stains should be performed on all non-blood specimens submitted
for anaerobic culture for several reasons
2. The presence of multiple distinct organism morphotypes suggests that the infection
is polymicrobic.
3. Certain morphotypes may provide a presumptive identification of the causative
organisms. E.g. Large, boxcar-like GPB suggest Clostridium species. Thin, fusiform
GNB suggest Fusobacterium.
4. Gram stain helps evaluate the quality of the specimen based on the presence and
number of SECs, that would suggest specimen contamination during collection.
5. Helps to identify morphotypes that were seen in Gram stain but not recovered in
culture. Different culture media may be needed or anaerobic culture conditions were
not initially met.
-Detect toxins directly in the specimen (e.g. C. difficile toxins in stool)
Question: T/F: Anaerobes direct examination includes gross &
microscopic exams and detect toxins
Ans✅ ✅: True
Question: Anaerobes: Culture Characteristics
Ans✅ ✅: 1. Media
a) Nutritious primary isolation media: prereduced, room temperature
1) CDC anaerobic blood agar & Brucella agar
2) Laked sheep blood with vitamin K
3) Broths
a) Thioglycollate
b) Chopped (cooked) meat
Question: Who am I?
