Complete this sentence: Negative staining procedures will:
stain the background, not the cell.
After being gram stained, gram positive bacteria are:
Blue
Gram negative bacteria have:
a thin layer of peptidoglycan in their cell wall
The following is a differential stain:
Gram stain
The organism on the upper half of this MSA plate (surrounded by a yellow halo) is what organism?
Staphylococcus aureus
The medium best suited for differentiation of Streptococci is
blood agar
An isolate is a gram-positive coccus, catalase-negative, and optochin-resistant. It is most likely:
viridans streptococci
Some streptococcal hemolysins can completely lyse red blood cells resulting in a clear zone around colonies on blood agar. This reaction is called:
beta-hemolysis
Staphylococcus epidermidis is able to grow on MSA. It tolerates the high salt but is unable to ferment the sugar in the medium. The sugar is:
mannitol
The genus Neisseria is characterized by
gram-negative diplococci with flattened adjacent sides
The organism that causes strep throat is
Streptococcus pyogenes
The most widely used method to evaluate the effectiveness of antibiotics against specific bacteria is
Kirby-Bauer method
Which of the following genera include pathogens of the intestinal tract?
Shigella
What color is an uninoculated citrate tube?
Green
Which medium is best for differentiating Streptococci?
Blood agar
Which medium is best for differentiating Staphylococci?
Mannitol Salt agar
Which medium is best for differentiating enterics?
Kligler Iron agar
Which medium would you choose to test for indol production?
pink or red
A KIA tube is inoculated and grown for 24 hours. It has a black butt, red slant, and no cracks or fissures. This is indicative of:
Glucose fermentation only
Which of the following KIA reactions will you most likely observe after growing E. Coli for 24 hours in a KIA tube?
A/A
The results of an IMViC series of tests is ++--. What color is at the surface of the SIM tube?
Red
The results of an IMViC series of test is --++. What color is the methyl red tube?
yellow
A sample of dirt is boiled for in water 10 minutes to kill all vegetative cells. After cooling, you inoculate a TSA plate with a small amount of the dirt. Several colonies grow overnight. The colonies are most likely of which genus?
Clostridium
Bacillus
Media in which some metabolic activity of an organism can be detected by inspection of the growth of the organism on the medium are referred to as:
Differential
The carbohydrate in MSA is
mannitol
Beta-hemolytic, bacitracin sensitive streptococci are growing well on a culture medium. The most likely organism is:
Staphylococcus pyogenes
Chocolate agar is used for growing fastidious bacteria.
True
Which of the following genera include pathogens of the intestinal tract?
Shigella
An isolate is a gram-positive coccus, catalase-negative, and optochin-susceptible. It is most likely
Staphylococcus pneumoniae
The mold hyphae you are viewing with your nouveau French microscope appears 156 times normal size. The ocular lens has a power of 12X. What is the power of the objective lens?
