MICROBIOLOGY EXAM 2 UAMS
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS ALREADY
PASSED!!!
Microbiology: Medicolegal Protocols & Urine Culture Quantification
What standard laboratory protocol must be followed in medicolegal cases
(e.g., sexual assault investigations) when an isolate appears to be Neisseria
gonorrhoeae?
✔✔ Perform at least two (2) confirmatory tests based on different
principles/methods (to ensure legal defensibility and rule out cross-reacting
commensal species).
What diagnostic methods are acceptable for confirming Neisseria gonorrhoeae
in medicolegal cases?
✔✔ ELISA, Nucleic Acid Probe, Direct Fluorescent Antibody (DFA), and
Nucleic Acid Amplification Tests (NAAT) (or culture paired with
biochemical/immunological confirmation).
What are the formulas and thresholds for calculating and reporting urine
colony counts (CFU/mL)?
✔✔ For a $1\ \mu\text{L}$ ($0.001\ \text{mL}$) loop:
What is the significance of three organisms in equal numbers on a urine culture?
Mixed flora; contaminated. Need new specimen.
What is a clue cell?
Vaginal epithelial cell with obscured edges; numerous organisms such as gram
negative, variable coccobacilli cover them
,What are clue cells associated with?
Bacterial vaginosis from Gardnerella vaginalis and a lack of lactobacillus (normal
flora)
How can gram-stained smears be used in the interpretation of culture results?
Used to confirm presence of organisms and determine cell morphology to properly
work up
Name six organisms that are part of the normal flora of humans
-Yeast
-Staph
-Strep
-Enterococci
-GNB
-Anaerobic cocci
How is Brucella transmitted?
It is zoonotic; usually transmitted through consumption of unpasteurized milk or
exposure to meat products (butchers)
,What are symptoms of Brucellosis?
Undulant fever or fever of unknown origin
How is Pasteurella multocida transmitted?
It is zoonotic; it is part of the normal flora of the upper respiratory tracts of cats
and dogs. It can be transmitted through bite or scratch.
How is Aeromonas transmitted?
Contact with contaminated food, water, or cold blooded animals.
How is Legionella transmitted?
Through airborne transmission; usually due to contact with contaminated food,
water, cooling towers, or showers.
What are the symptoms of Legionnaire's disease?
Acute pneumonia, high fever, and prostration
True or False: Chlamydia trachomatis is transmitted through direct contact
, True
What is the desired specimen for diagnosing Chlamydia trachomatis?
Epithelial cells of the involved sites collected by vigorous swabbing or scraping.
Usual sites: cervix, urethra, conjunctiva, nasopharynx
Laboratories must perform QC on certain media even though manufacturers have
documented that the media meets NCCLS standards. Name three of these media.
CHOC, CAMPY-BAP, Neisseria media
Indicate the typical colony morphology of E. coli on the following media.
-EMB
-MAC
-SS
-HE
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS ALREADY
PASSED!!!
Microbiology: Medicolegal Protocols & Urine Culture Quantification
What standard laboratory protocol must be followed in medicolegal cases
(e.g., sexual assault investigations) when an isolate appears to be Neisseria
gonorrhoeae?
✔✔ Perform at least two (2) confirmatory tests based on different
principles/methods (to ensure legal defensibility and rule out cross-reacting
commensal species).
What diagnostic methods are acceptable for confirming Neisseria gonorrhoeae
in medicolegal cases?
✔✔ ELISA, Nucleic Acid Probe, Direct Fluorescent Antibody (DFA), and
Nucleic Acid Amplification Tests (NAAT) (or culture paired with
biochemical/immunological confirmation).
What are the formulas and thresholds for calculating and reporting urine
colony counts (CFU/mL)?
✔✔ For a $1\ \mu\text{L}$ ($0.001\ \text{mL}$) loop:
What is the significance of three organisms in equal numbers on a urine culture?
Mixed flora; contaminated. Need new specimen.
What is a clue cell?
Vaginal epithelial cell with obscured edges; numerous organisms such as gram
negative, variable coccobacilli cover them
,What are clue cells associated with?
Bacterial vaginosis from Gardnerella vaginalis and a lack of lactobacillus (normal
flora)
How can gram-stained smears be used in the interpretation of culture results?
Used to confirm presence of organisms and determine cell morphology to properly
work up
Name six organisms that are part of the normal flora of humans
-Yeast
-Staph
-Strep
-Enterococci
-GNB
-Anaerobic cocci
How is Brucella transmitted?
It is zoonotic; usually transmitted through consumption of unpasteurized milk or
exposure to meat products (butchers)
,What are symptoms of Brucellosis?
Undulant fever or fever of unknown origin
How is Pasteurella multocida transmitted?
It is zoonotic; it is part of the normal flora of the upper respiratory tracts of cats
and dogs. It can be transmitted through bite or scratch.
How is Aeromonas transmitted?
Contact with contaminated food, water, or cold blooded animals.
How is Legionella transmitted?
Through airborne transmission; usually due to contact with contaminated food,
water, cooling towers, or showers.
What are the symptoms of Legionnaire's disease?
Acute pneumonia, high fever, and prostration
True or False: Chlamydia trachomatis is transmitted through direct contact
, True
What is the desired specimen for diagnosing Chlamydia trachomatis?
Epithelial cells of the involved sites collected by vigorous swabbing or scraping.
Usual sites: cervix, urethra, conjunctiva, nasopharynx
Laboratories must perform QC on certain media even though manufacturers have
documented that the media meets NCCLS standards. Name three of these media.
CHOC, CAMPY-BAP, Neisseria media
Indicate the typical colony morphology of E. coli on the following media.
-EMB
-MAC
-SS
-HE
