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Flashcards in L16_Cocci Deck (55):
1

What is the diameter of cocci?

1um

2

Are cocci spore forming?

No

3

What are the only reservoir for cocci?

Humans

4

Can cocci be cultured easily?

Yes

5

What are the 5 relevant streptococci species?

Group A (sore throats), Group B (meningitis), Pneumococci (pneumonia), Viridans Streptococci (Endocarditis), Enterococci (Abscesses)

6

What are the 3 relevant Staphylococci species?

S. Aureus (abscesses), S. Epidermidis (Catheters), S. saprophyticus (UTI)

7

What are the 2 relevant Neisseria species?

N. meningitides, N. gonorrhoeae

8

What does the catalase test test for?

Ability to break down H2O2

9

How can you identify streptococci?

Gram Positive, Catalase negative, chains

10

What are the possible results of a hemolysis test, and what do they represent?

Beta= completely breakdown
alpha= partially break down
gamma= do not break down

11

Describe the test results that identify group A strep

Gram positive, catalase negative, beta hemolytic, bacitracin sensitive

12

Describe the test results that identify group B strep

Gram positive, catalase negative, beta hemolytic, bacitracin resistant

13

What are the virulence factors of Group A strep (structural and toxins)

Structural: Pili and M protein
Toxins: streptokinase (breaks blood clots), streptodornase, hyaluronidase (breaks down tissue), pyrogenic toxin, erythrogenic toxin

14

What kind of infections do group A strep cause?

Surface infections (sore throats), they spread, they cause fever

15

What is the reservoir and transmission for group A strep

carriers or infected patients, and direct contact. (Dogs can carry too)

16

What are 3 possible sequelae that can be observed a couple weeks after a group A strep infection?

streptococcal nephritis (After Strep B)
Rheumatic Fever (after Strep A)
Sydenham's chorea (OCD)
Non show signs of the bacteria, this is after they are cleared

17

Are there rapid office tests for Group A strep?

Yes but they a less sensitive.

18

What species is Group A strep?

S. pyogenes

19

How can you type Group B strep in the lab?

Gram positive, catalase negative, beta hemolytic, bacitracin resistant

20

What species is Group B strep?

S. agalactiae

21

What is the CAMP test? and what does it comfirm

The hemolytic toxins of S. aureus and group B strep are synergistic. This test shows that where the toxins meet that hemolysis increases and confirms that you strep is group B

22

What is the virulence factor of Group B strep?

Capsule

23

What is the reservoir and transmission of group B strep

Reservoir is genital tract and transmission is neonatal- to baby

24

What antibiotic are Group B always sensitive to?

Penicillin

25

Is there a vaccine for strep group A or B?

No

26

How would you identify Streptococci pneumoniae in the lab?

Gram positive, catalase negative, alpha hemolytic, bile/optochin sensitive

27

What clumping pattern do S. Pneumoniae show?

dipplococci

28

What is the virulence factor of S. pneumoniae?

Capsule

29

How can capsule of S. pneumoniae be used in the lab?

serotyping and vaccine (not great vaccine)

30

What is the reservoir for S. pneumoniae

Humans

31

What is the main mechanism of resistance against pneumococci?

mechanical clearance by mucus and cilia sweep it out of the respiratory tract and it gets swallowed and killed in the GI tract

32

Why do alcoholics get bacterial pneumonia frequently?

depressed cough reflex

33

how do you identify Strep Viridans in the lab?

Gram pos, catalase neg, alpha hemolytic, bile/optochin resistant

34

What is the reservoir and virulence factors of Viridans Streptococci?

Mouth of people 100%, sugar metabolizing enzymes (can break down into acids which decalcify, or they can build up into dental plague and release can cause bacteremia and endocarditis) They are Sticky

35

how do you treat S. Viridans?

Penicillin

36

How do you type streptococci faecalis in the lab?

Gram pos, catalase negative, gamma hemolytic, bile/optochin resistant

37

How do you ID staphylococci in the lab?

Gram pos, catalase pos

38

How do you ID S. aureus in the lab?

Gram pos, catalase pos, coagulase pos

39

What are the virulence factors of S. Aureus?

Structural: Protein A, capsule, coagulase
Toxins: DNAse, enterotoxin, exfoliatin, toxic shock syndrom, leukocidin

40

Do S. Aureus infections tend to spread?

No they tend to stay where they are and cause abscesses

41

What is a major problem of S. aureus?

They are multi drug resistant

42

How do you ID Staph epidermidis in the lab?

Gram positive, catalase positive, coagulase negative, novobiocin sensitive

43

Where do you find S. epidermidis infections a lot?

infections with piercings, and catheter surfaces

44

How do you ID S. saprophyticus?

gram positive, catalase positive, coagulase negative, novobiocin resistant

45

How do you ID N. meningitidis?

Gram neg, fermentation of maltose on chocolate agar

46

How do you ID N. gonnorhoeae?

Gram Neg, no fermentation of maltose on chocolate agar

47

What is the virulence factors of N. meningitidis?

capsule and LPS

48

What is the virulence factors of N. gonorrhoeae?

pili and LOS

49

Where does meningitidis cause infections? gonorrhoeae?

meningitidis - deeper tissues
Gonorhheae - surfaces

50

What is the reservoir, transmission and prevention of N. Meningitidis?

Reservoir is resp. tract and carriers
transmission is droplets
Prevention is Vaccine

51

What is the reservoir, transmission and prevention of N. Gonorrhoeae?

Reservoir: genital tract and chronic infection
Transmission: sexual contact and birth
Prevention: Behavioral and Neonatal eye drops

52

How do you treat N.Meningitidis vs N. Gonorrhoeae?

Menigitidis- penicillin
Gonorrhoeae- Not penicillin (its resistant) Ceftriaxone plus doxycycline

53

What are the two Cocci that can have a vaccine made for them?

S. pneumoniae and N. Meningitidis

54

How does Lancefield typing work?

by identifying carbohydrate antigens

55

What does the capsule of pneumococci cause the immune system to do?

Produce opsonizing antibody