BacT Final Flashcards
A urine sample is received in the laboratory for culture. If the specimen can not be plated immediately, it should be held:
in refrigeration
Which of the following media are both selective and differential?
Mannitol salt agar
A TSI medium is inoculated on Monday. On Wednesday, the TSI tube is completely pink. The microbiologist should report the reaction:
Inoculate a fresh TSI tube and incubate for 18-24 hours
Which of the following sets of specimens would be acceptable for anaerobic culture?
pleural fluid, brain abscess
The pH indicators neutral red and phenol red indicate the acidity in the medium by showing the color change as:
Red and yellow respectively
When acetone-alcohol (decolorizer) is intentionally omitted from the gram-stain procedure, streptococci and Neisseriae will be stain respectively:
purple and purple
Slide coagulase test is positive for an organism because:
clumping factor found on the cell wall reacts with plasma fibrinogen
A LIA slant shows a burgundy-red slant over a yellow butt. This reaction indicated that the organism:
deaminated lysine
Decarboyxlation of amino acids lysine, arginine and ornithine results in the formation of which of the major compounds:
amines
The medium used to determine whether an organism is oxidative or fermentative with respect to its metabolic activities is:
O-F medium
Factors influencing recovery and detection of microbial pathogens from specimens include:
transit time, storage temperature and sampling technique
A swab is not the appropriate collection device to use when collecting body fluid for culture because:
the amount of sample volume that can be collected is limited
The Gram reaction of a microorganism is determined by the composition of its:
cell wall
You receive a sputum specimen. It should be inoculated onto:
blood agar, chocolate agar, and MacConkey agar
An unlabeled specimen is received in the laboratory. Your best course of action would be:
reject and request another specimen
What is the specimen of choice for pharyngitis or sore throat?
Swab of throat exudate
If an organism shows growth on phenylethyl alcohol agar (PEA) and no growth on MacConkey (MAC) the organism is most likely:
Gram-positive
Select the method of choice for recovery of anaerobic bacteria from a deep abscess
Needle aspirate after surface decontamination
A positive Simmons citrate test is seen as a
Blue color in the medium after 24 hours incubation at 35*C
Which of the following reagents is added to detect the production of indole?
p-Dimethylaminobenzaldehyde (Kovac’s reagent)
Shigella species characteristically are:
non-motile
Streptococcus pneumoniae can be differentiated best from viridans streptococci by:
bile solubility
A yellow colony from a wound culture tested catalase-positive and coagulase-negative. The organism stained as gram-positive cocci in clusters. Which of the tests would differentiate between a coagulase-negative Staphylococcus and Micrococcus?
Bacitracin susceptibility
While swimming in a lake, a young boy cut his foot, and an infection developed. The culture grew a nonfastidious, gram-negative, oxidase positive, beta-hemolytic, motile bacilli. The most likely identification is:
Aeromonas hydrophila
Explosive watery diarrhea with severe abdominal pain, after eating raw shellfish is most indicative of infection caused by:
Vibrio parahemolyticus
All members of Enterobacteriaceae family have the following characteristics except:
capable of fermenting lactose
Which of the following tests should be done first in order to differentiate Aeromonas species from members of Enterobacteriaceae
Oxidase
Hemolytic uremic syndrome (HUS) is complication after infection with:
E. coli O157:H7