Micro - Bacteriology (Part 1) Flashcards Preview

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Flashcards in Micro - Bacteriology (Part 1) Deck (200)
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1

A patient presents to your clinic with this painless lesion on his penis. What is the most likely diagnosis?

Syphilis

2

What medication should be given for prophylaxis after a close contact is infected with the organism shown?

Rifampin

3

A 25-year-old woman presents with vaginal discharge that looks like this on microscopy. What is your diagnosis and treatment plan?

Gardnerella vaginalis infection; treatment with metronidazole

4

What type of organisms stain purple/blue with Gram staining?

Gram-positive organisms

5

Gram-positive organisms are commonly classified into which two shapes?

Cocci or rods (bacilli)

6

Name four gram-positive rods.

Clostridium, Listeria, Bacillus, and Corynebacterium

7

Name one gram-positive anaerobic rod.

Clostridium

8

Staphylococcus and Streptococcus are differentiated by which enzyme?

Catalase; Staphylococcus is catalase positive, and Streptococcus is catalase negative

9

Which gram-positive cocci are found in clusters?

Staphylococcus

10

Which gram-positive cocci are found in chains?

Streptococcus

11

What differentiates Staphylococcus aureus from and other staph species?

Other staph species are coagulase negative

12

Name two coagulase-negative Staphylococcus species.

Staphylococcus saprophyticus and Staphylococcus epidermidis

13

Which Staphylococcus species is novobiocin sensitive?

Staphylococcus epidermidis

14

Which Staphylococcus species is novobiocin resistant?

Staphylococcus saprophyticus

15

If agar shows clear hemolysis, which Streptococcus species could be present?

Streptococcus pyogenes or Streptococcus agalactiae

16

What type of hemolysis do both group A and group B streptococci have in common?

β-Hemolysis

17

Streptococcus pyogenes is a type of group _____ Streptococcus, whereas Streptococcus agalactiae is a type of group _____ Streptococcus.

A, B

18

How are -hemolytic streptococci differentiated from each other?

By their bacitracin sensitivity (Streptococcus pyogenes is sensitive, Streptococcus agalactiae is resistant)

19

Name two streptococci that are -hemolytic.

Enterococcus and Peptostreptococcus (anaerobic)

20

True or False: Enterococcus faecalis is a -hemolytic, gram-positive, catalase-negative cocci.

True

21

Which -hemolytic streptococcal species is bacitracin resistant?

Group B Streptococcus (Streptococcus agalactiae)

22

Which -hemolytic streptococcal species is bacitracin sensitive?

Group A Streptococcus (Streptococcus pyogenes)

23

Staphylococcus saprophyticus is novobiocin _____ (resistant, sensitive); staphylococcus epidermidis is novobiocin _____ (resistant, sensitive).

Resistant; sensitive (remember: On the staph retreat there was NO StRES; Novobiocin: Saprophyticus Resistant, Epidermidis Sensitive)

24

Group A streptococci are bacitracin _____ (resistant, sensitive); group B streptococci are bacitracin _____ (resistant, sensitive).

Sensitive; resistant (remember: Bacitracin: group B are Resistant, whereas group A are Sensitive (B-BRAS)

25

Streptococcus viridans is optochin _____ (resistant, sensitive); streptococcus pneumoniae is optochin _____ (resistant, sensitive).

Resistant; sensitive (remember, Optochin: Viridans Resistant and Pneumonia Sensitive; OVRPS- overpass)

26

What bacterial enzyme degrades hydrogen peroxide?

Catalase

27

What antimicrobial product produced by polymorphonuclear lymphocytes is a substrate for myeloperoxidase?

Hydrogen peroxide

28

Which gram-positive cocci are catalase positive?

Staphylococci

29

What differentiates Staphylococcus aureus from Staphylococcus epidermidis and Staphylococcus saprophyticus?

Coagulase (Staphylococcus aureus is coagulase positive)

30

Why do people with chronic granulomatous disease (nicotinamide adenine dinucleotide phosphate oxidase deficiency) get recurrent infections by catalase-producing organisms?

Bacterial catalase easily degrades the little hydrogen peroxide produced, compromising the ability of neutrophils to kill bacteria