Gram (+) Rods Flashcards
Movement of Listeria monocytogenes inside of host cells is caused by?
a. Pseudopod formation
b. Tumbling motility
c. Inducing host cell polymerization
d. Formation of fimbriae on listeria surface
C
Explanation: In the pathogenesis of L. monocytogenes: After cell lysis by Listeriolysin O and phospholipases, the organism proliferates ActA inducing host cell actin
polymerization. This shall propel them to the cell membrane
[2023 Trans]
What is the characteristic appearance of Corynebacteria under the microscope?
a. Grape-like clusters
b. Chinese character like
c. Bacilli with end-to-end motility
d. None of the above
B
What is the causative agent of Actinomycetomas?
a. Corynebacterium urealyticum
b. Nocardia brasiliense
c. Erysipelothrix rhusiopathiae
d. Rhodococcus sp
B
Which of the following are spore-forming bacteria?
a. Bacillus
b. Nocardia
c. Listeria
d. Corynebacterium
A
Which virulence factor enables Listeria to survive intracellularly and lyse the phagolysosomal membrane allowing listeria to escape into the cytoplasm?
a. Listeriolysin O
b. ActA
c. Internalin
d. Siderophore
A
Which food is commonly associated with Bacillus cereus food poisoning?
a. Baked potato
b. Fried rice
c. Honey
d. Raw sprouts
B
What is the causative agent of Actinomycetomas?
a. Rhodococcus sp.
b. Erysipelothrix rhusiopathiae
c. Corynebacterium urealyticum
d. Nocardia brasiliense
D
A localized infection of the finger called the “seal finger” is caused by which organism?
a. Corynebacterium urealyticum
b. Erysipelothrix rhusiopathiae
c. Nocardia asteroides
d. Rhodococcus sp.
B
Which of the following bacteria are members of the normal skin flora that is often considered an opportunistic pathogen sometimes causing Acne vulgaris?
a. Cutibacterium spp.
b. Staphylococcus aureus
c. Micrococcus spp.
d. Staphylococcus epidermidis
A
B. Cutibacterium spp (old name: propionibacterium acnes)
Which of the following biochemical tests is helpful to distinguish Erysipelothrix from other gram positive rods?
a. Catalase positivity
b. Acid fastness
c. Production of H2S
d. Urease positivity
C
Erysipelothrix is NEGATIVE in - catalase, oxidase, and indole test - non acid fast - urease negative Acid fastness test for Nocardia Urease positive to distinguish C. diptheriae and other Corynebacterium
A 7-day old infant presents to the ER due to fever, poor feeding, and a bulging fontanelle. During physical examination, she developed a seizure. A gram stain of the CSF reveals gram positive rods. Which of the following organisms is the most likely causative agent?
a. Streptococcus agalactiae
b. Neisseria meningitidis
c. Listeria monocytogenes
d. Escherichia coli
C
Seizure - typical of gram positive rods
Only gram positive rod among the choices - listeria
Which of the following gram-positive bacilli is branching AND modified acid-fast positive which causes Madura foot?
a. Streptomyces spp
b. Erysipelothrix rhusiopathiae
c. Listeria monocytogenes
d. Nocardia brasiliensis
D
Madura foot or Mycetoma is caused by N. brasiliensis
A 3-year old girl was brought to the ER due to fever, cough, and
difficulty of breathing of 3 days duration. On physical
examination, you note a grayish membrane on the tonsillar area, which bleeds upon manipulation. Which diagnostic test will help
you in your diagnosis?
a. Throat swab culture
b. CSF culture
c. Blood culture
d. Serum ELISA
A
Diagnosis: Diphtheria
Most appropriate - Throat swab culture
Which of the following selective culture media will aid in the identification of Corynebacterium diphtheriae?
a. Mannitol salt agar
b. Cystine-Tellurite blood agar
c. Thayer-Martin media
d. Thiosulfate citrate bile salt sucrose agar
B
A - Staphylococcus spp.
C - Neisseria spp. (gold standard)
D - V. cholerae
Which of the following is NOT a laboratory feature of Bacilus cereus?
a. Medusa head colonies on blood agar
b. Endospores on special stain
c. Beta-hemolytic colonies on blood agar
d. Demonstrates white colonies on blood agar
A
C. medusa head - anthrax
