Group B Streptococci Flashcards

1
Q

What are examples of Group B streptococci?

A
  1. Strep Virdans

2. Strep agalactiae

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2
Q

Characteristics of Streptococci virdans?

A

Gram positive cocci in pairs or chains
part of human flora
catalase negative
Facultative anaerobes

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3
Q

Optochin resistant organism?

A

Strep. Viridans

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4
Q

Optochin sensitive organism?

A

Strep. Penumoniae

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5
Q

Bile resistant organism?

A

Enterococcus (group d)

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6
Q

Bacitracin resistant organism?

A

Strep. agalactiae (group b)

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7
Q

Bacitracin sensitive organism?

A

Strep. Pyogenes

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8
Q

Microbiological properties of Strep. agalactiae?

A
  • Gram positive, cocci
  • encapsulated
  • Group B lancefield antigen
  • CAMP test positive
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9
Q

Which organisms are B-hemolytic?

A

Strep. Pyogenes and Strep. Agalactiae

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10
Q

Which organism is Gamma-hemolytic?

A

Enterococcus

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11
Q

Which organisms are Alpha-hemolytic?

A

Strep. pneumonia and Strep. Viridans

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12
Q

Strep Viridans includes what organisms?

A

Strep. mutans, songuis, milleri, mitis

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13
Q

What is the most important VF of Strep. Agalactiae?

A

Capsule is imp. VF

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14
Q

What capsule types are associated with early onset neonatal disease?

A

Type 1a, III and V

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15
Q

Which capsule is commonly associated with Late onset disease?

A

Type III

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16
Q

Which capsule types are most common in adults?

A

1a and V

17
Q

Which toxin from Strep. Agalactiae is toxic to neutrophils?

A

CylE pre forming toxin

18
Q

What is the epidemiology of Strep. Agalactiae?

A
  • Most common cause of septicemia and meningitis in newborns.
  • 25% of pregnant women have Group B Strep (GBS) in vagina or rectum
19
Q

Presence of GBS between what weeks of gestation are of most concern?

A

Weeks 35-37

20
Q

What are the stages of neonatal infection?

A
  1. Colonization of pregnant mother
  2. Ascending placental and Uterine infection
  3. Pneumonia/Lung injury
  4. Bacteremia and Sepsis syndrome
  5. BBB penetration and meningitis
21
Q

Strep. Agalactiae infections in pregnant women results in what?

A
  • Postpartum endometritis
  • Wound infection
  • UTI
22
Q

Strep Agalactiae lab diagnosis to detect vaginal carriage in pregnant women?

A

PCR-based assays

23
Q

What tests do you use to identify Isolates?

A

Positive CAMP test

Hippurate hydrolysis

24
Q

The CAMP test examines what?

A

examines interaction of presumptive GBS with S.aureus in co-culture.

25
Q

A positive CAMP test is indicated by what?

A

Enhanced hemolysis closest to S. aureus (characteristic arrowhead pattern)

26
Q

GBS enhances S.aureus hemolysis how?

A

by secreting diffusible CAMP factor

27
Q

What is the drug of choice for GBS?

A

Penicillin

28
Q

What drugs can you use to serious infections with GBS?

A

Ampicillin with an aminoglycosides or a cephalosporin

29
Q

If patient is allergic to penicillin or ampicillin what can you give to a patient who has GBS?

A

Clindamycin or vancomycin

30
Q

For high risk babies, what is given to the mothers before delivery?

A

Penicillin is given to mother 4 hours before delivery

31
Q

Strep. mutans and Strep. sanguis are found where?

A

Commensal found in oral cavity, GIT and genitourinary tract

32
Q

characteristics of Strep. mutans and Strep. sanguis?

A
  • Gram positive cocci chain
  • Indistinguishable from S. pyogenes in gram smear.
  • Optochin resistant
  • Nosocomial (hospital acquired)
33
Q

Pathogenesis of Strep. mutans and sanguis?

A

S. mutans Dextran mediated adherence glue the oral flora onto the tooth enamel or damaged heart valve and to each other (vegetation)

34
Q

What are the diseases Strep. mutans and sanguis causes?

A
  1. Native valve subacute bacterial endocarditis

2. Dental caries (tooth decay)

35
Q

What are the clinical manifestations of Native valve subacute bacterial endocarditic?

A

Murmur, anorexia, night sweats, weight loss, etc.

36
Q

RANDOM!!

what causes acute bacterial endocarditis? what causes prosthetic valve endocarditis?

A

Staph. Aureus

Staph. Epidermidis

37
Q

What is the treatment for Strep. mutans and sanguis?

A

Penicillin G with aminoglycosides for endocarditis.