Streptococci II

Question 1

Streptococcus agalactiae

Hemolysis
Bacitracin susceptibility
Group type

Answer 1

Beta-hemolysis
Bacitracin resistance
Group B

Question 2

What patient population most commonly gets infected with Strep agalactiae?

Answer 2

Women in peripartum period and in newborns

Question 3

What 3 ways does early-onset neonatal Strep agalactiae infection present?

Answer 3

• Bacteremia without an identifiable focus
• Pneumonia
• Meningitis

Question 4

How does late onset neonatal Strep agalactiae infection present?

Answer 4

Bacteremia w/ meningitis

Question 5

How does maternal Strep agalactiae usually manifest?

Answer 5

Complication of pregnancy (endometritis and/or wound infection after Cesarian)

Question 6

What types of adult individuals typically develop group B strep disease (besides peripartum women)?

Answer 6

People with underlying illnesses (diabetes is most common)

Question 7

Are Group B strep susceptible to penicillin?

Answer 7

Yes

Question 8

Streptococcus gallolyticus (bovis)

Group type
Hemolysis
Penicillin sensitivity

Answer 8

Group D
Gamma-hemolysis
Penicillin sensitive

Question 9

Diseases associated with Strep gallolyticus

Answer 9

Bacteremia & endocarditis due to lesions from mouth to anus, but adenocarcinoma of colon is strongest

Question 10

What procedure must you perform on patients who have S. gallolyticus bacteremia or endocarditis?

Answer 10

Colonoscopy to screen for cancer

Question 11

Enterococcus faecalis & E. faecium

Group type
Hemolysis
Penicillin sensitivity
Associated diseases

Answer 11

• Group D
• Gamma-hemolysis
• Tolerant (penicillin will kill it, but you’d need a LOT of it)
• Endocarditis, UTI’s, meningitis as a result of surgery or strongiloides

Question 12

What Group D bacteria constitute substantial portion of normal bowel flora?

Answer 12

Enterococcus

Question 13

T or F. Enterococci are not as intrinsically virulent as other strep.

Answer 13

TRUE - usually cause infections in areas that have been previously damaged

Question 14

What types of patients normally get enterococcal infections? Why?

Answer 14

Hospitalized patients - can be transferred on hands of health care personnel, can survive for prolonged periods in inanimate environment, surgery & invasive procedures as well as prior antibiotic therapy predispose to colonization

Question 15

What streptococcus species are sexually promiscuous? How is this advantageous?

Answer 15

Enterococci - means they gain lots of abilities for antibiotic resistance

Question 16

What mechanisms do enterococci have that provide them with resistance to a # of antibiotics?

Answer 16

1. High-level aminoglycoside resistance
2. Alterations of penicillin-binding proteins
3. Beta-lactamase production
4. Vancomycin resistance due to altered terminal D-ala D-ala on peptidoglycan side chain

Question 17

For Group C and Group G strep, what types of patients are commonly infected?

Answer 17

Those with underlying diseases

Question 18

• S. mitis
• S. sanguis
• S. salivarious
• S. mutans

Group
Hemolysis
Optochin susceptibility
Bile salts solubility
Associated diseases

Answer 18

• Viridans streptococci
• alpha-hemolytic
• Optochin resistant
• Insoluble in bile salts
• Dental caries, most common cause of infective endocarditis, meningitis

Question 19

• S. anginosus
• S. constellatus
• S. intermedius

Group
Hemolysis
Oxygen use
Associated diseases

Answer 19

Strep anginosus or Milleri group
Gamma-hemolysis

Microaerophilic streptococci that cause abscesses, infective endocarditis (very very rare) - normal constituents of human bowel that cause disease when they spread to normally sterile areas through blood or directly

Question 20

Fish pathogen - causes subcutaneous abscesses in Amazon freshwater dolphins and fishponds

Answer 20

Streptococcus iniae

Question 21

Peptococcus, Peptostreptococcus

Answer 21

Anaerobic strep that are normal constituents of microbial flora of GI and female GU tract, cause problems when they end up in normally sterile locations b/c of altered anatomy, poorly perfused tissues, or trauma

Question 22

What antibiotics would you treat Enterococcus infection with and why?

Answer 22

Ampicillin + gentamicin (penicillin + aminoglycoside)

Penicillin is the drug of choice, but you’d need a LOT of it for it to work, so create a synergy effect by adding aminoglycoside