8.6 Flashcards
Large gram-positive spore-forming rods growing on blood agar as large, raised, B-hemolytic colonies that spread and appear as frosted green-gray glass are most likely
A. Pseudomonas spp.
B. Bacillus spp.
C. Corynebacterium spp.
D. Listeria spp.
B. Bacillus spp.
Bacillus anthracis and Bacillus cereus can best be differentiate by which test?
B-hemo; motility; oxidase; catalase; lecithinase; glucose
B.cereus: +; +; Neg: +; +; +
B.anthracis: Neg; Neg; Neg: +; +; +
A. Motility and B-hemolysis on a blood agar plate
B. Oxidase and B-hemolysis on a blood agar plate
C. Lecithinase and glucose
D. Lecithinase and catalase
A. Motility and B-hemolysis on a blood agar plate
Which is the specimen of choice for proof of food poisoning by Bacillus cereus?
A. Sputum
B. Blood
C. Stool
D. Food
D. Food
A suspected Bacillus antrhacis culture obtained from a wound specimen produced colonies that had many outgrowths (Medusa-head appearance), but were not B-hemolytic on sheep blood agar. Which test should be performed next?
A. Penicillin (10-unit) susceptibility test
B. Lecithinase test
C. Glucose test
D. Motility test
A. Penicillin (10-unit) susceptibility test
Which of the following test should be performed for initial differentiation of Listeria monocytogenes from group B streptococci?
A. Gram stain, motility at room temperature, catalase
B. Gram stain, Camp test, H2S/TSI
C. Oxidase, CAMP test, glucose
D. Oxidase, bacitracin
A. Gram stain, motility at room temperature, catalase
Culture of a finger wound specimen from a meat packer produced short gram-positive bacilli on a blood agar plate with no hemolysis. Given the following test results at 48 hours, what is the most likely identification?
-Catalase=Neg
-Motility(wet prep)=Neg
-Motility (media)=Neg (bottle-brush growth in stab culture)
A. Bacillus cereus
B. Listeria monocytogenes
C. Erysipelothrix rhusiopathiae
D. Bacillus subtilis
C. Erysipelothrix rhusiopathiae
A non-spore-forming, slender gram-positive rod forming palisades and chains was recovered from a vaginal culture and grew well on tomato juice agar. The most likely identification is:
A. Lactobacillus spp.
B. Bacillus spp.
C. Neisseria spp.
D. Streptococcus spp.
A. Lactobacillus spp.
A Corynebacterium species recovered from a throat culture is considered a pathogen when it produces:
A. A pseudomembrane of the oropharynx
B. An exotoxin
C. Gray-black colonies with a brown halo on Tinsdale’s agar
D. All of these options
D. All of these options
A presumptive diagnosis of Gardnerella vaginalis can be made using which of the following findings?
A. Oxidase and catalase tests
B. Pleumorphic bacilli heavily colonized on vaginal epithelium
C. Hippurate hydrolysis test
D. All of these options
D. All of these options
A gram-positive branching filamentous organism recovered from a sputum specimen was found to be positive with a modified acid-fast stain method. What is the most likely presumptive identification?
A. Bacillus spp.
B. Nocardia spp.
C. Corynebacterium spp.
D. Listeria spp.
B. Nocardia spp.
Routine laboratory testing for Treponema pallidum involves:
A. Culturing
B. Serological analysis
C. Acid-fast staining
D. Gram staining
B. Serological analysis
Spirochetes often detected in the hematology laboratory, even before the physician suspects the infections, are:
A. Borrelia spp.
B. Treponema spp.
C. Campylobacter spp.
D. Leptospira spp.
A. Borrelia spp.
Which of the following organisms is the cause of Lyme disease?
A. Treponema pallidum
B. Neisseria meningitidis
C. Babesia microti
D. Borrelia burgdorferi
D. Borrelia burgdorferi
The diagnostic method most commonly used for the identification of Lyme disease is:
A. Serology
B. Culture
C. Gram stain
D. Acid-fast stain
A. Serology
Primary atypical pneumonia is caused by:
A. Streptococcus pneumoniae
B. Mycoplasma pneumoniae
C. Klebsiella pneumoniae
D. Mycobacterium tuberculosis
B. Mycoplasma pneumoniae
