CNS Infections- Neonate- GBS

Question 1

The single most important predisposing factor for neonate to get meningitis is __________

Answer 1

Low birth weight

1. Low birth weight (LBW;

Question 2

What factors predispose the LBW, VLBW, and ELBW infant to infection?

Answer 2

1. Impaired innate and adaptive immune functions
2. Require nosocomial techniques and devices to keep them alive (catheters, feeding tubes, suction tubes)
3. Incidence of sepsis is much higher in the premature infant than in the full-term infant
4. Maternally related events allow agent access to fetus before birth or during parturition (premature rupture of membranes, maternal infection during last week of pregnancy, vaginosis, UTI, cervicitis, chorioamnionitis, excessive manipulation during delivery, use of intrauterine monitoring devices)
5. Source of etiologic agent (in utero, during parturition, hours/days post part from parents)

Question 3

S/S of neonatal meningitis (NOT the same as adults)

Answer 3

1. Fever.
2. Lethargy.
3. Poor feeding.
4. GI disturbance (vomiting/diarrhea)/abdominal distension.
5. Respiratory abnormalities (e.g., dyspnea, cyanosis)
6. Cardiac abnormalities (tachycardia).
7. Bulging fontanelle

Question 4

Prognosis for neonatal meningitis is

Answer 4

poor (mortality rates are 10-60%, survivors show some permanent defects, usually neuron)

Question 5

Etiologic agent predominately seen in neonates

Answer 5

Streptococcus agalactiae

AKA- Group B Streptococci (GBS)

Question 6

Group B Streptococci (GBS)

Answer 6

• β-hemolytic on sheep blood agar via production of the ornithine rhamnolipid pigment or lipid toxin
• Bacitracin-resistant versus GAS, which is bacitracin- sensitive.
• Has capsular polysaccharide (serotypes based on this)
• Major virulence factor - antiphagocytic
• 9 groups: Five groups (especially Group III) are most common causes of both early and late onset disease

Question 7

S. agalactiae is the leading cause of

Answer 7

bacteremia alone or (with meningitis and/or pneumonia as complications) within the first 3 months of life
-highest incidence in preterm but most cases occur in full term infants

Question 8

1/3 of all invasive GBS disease occurs in

Answer 8

pregnant women

Maternal UTI caused by GBS often occurs before or just after birth

Question 9

Clinical GBS syndromes occur in

Answer 9

virtually all tissues/organs

Question 10

2 forms of neonatal disease are

1. early (acute) onset sepsis (bacteremia)
2. late (insidious) onset sepsis (bacteremia or focal infection)

Describe them

Answer 10

Early:

1. Occurs within the first 6 days after birth.
2. Source is mother, infection is acquired in utero or via passage through birth canal.
3. More common form of disease (80% of cases).

Late:

1. Occurs 7 days → 3 months following birth.
2. Source: associated with postpartum acquisition in the nursery (care givers) or community or mothers.
3. Focal infections include meningitis, cellulitis, osteomyelitis, septic arthritis.
4. Less common form of this disease (20% of cases

Question 11

Meningitis occurs in _____ cases of early onset sepsis, but ______ cases of late onset sepsis.

Because of the higher mortality rate and the occurrence of neurological sequelae associated with meningitis, have a high index of suspicion for meningitis

Answer 11

few (5%)

many (30%)

Question 12

Neonatal meningitis immunity

Answer 12

Mast cells in vagina and cervix come in contact with pathogen and contribute to proinflammatory response. The hemolytic GBS pigment triggers mast cell degranulation, resulting in the release of preformed and pro inflammatory mediators. This degranulation decreases systemic virulence and diminishes vaginal colonization. Mast cell degranulation in the lower genital tract can limit colonization of hyper pigmented GBS strains.

Question 13

Treatment

Answer 13

Antibiotic resistance is occurring but penicillin G remains drug of choice

Question 14

Prevention of GBS

Answer 14

1. The screening approach specifies that all pregnant mothers be screened at 35→37 weeks gestation
   - All identified carriers and women who deliver pre-term before screening can be done should be offered intrapartum antimicrobial prophylaxis iv: Penicillin G at an initial dose of 5,000,000 U, then 2,500,000 U every 4 hours until delivery) and Ampicillin
2. The risk factors assessment (non screening) approach specifies that intrapartum antimicrobial agents (same antibiotics as stated above administered iv) should be offered to any pregnant women with 1 or more of the following risk factors:
   a. elevated intrapartum temperature.
   b. membrane rupture > 18 hours.
   c. premature onset of labor.
   d. premature rupture of membrane (PROM) at

Question 15

What can be used as an alternative for women allergic to penicillin?

Answer 15

Cefazolin

Question 16

_______ is reserved for patients with a high anaphylactic risk and those for whom susceptibility to erythromycin and clindamycin has not been performed or has been found resistant

Answer 16

Vancomycin

Question 17

Antibiotic prophylaxis before labor starts and single administration of postpartum antibiotic prophylaxis for newborns are proven to be __________

Answer 17

ineffective

Question 18

Prevention strategy for late onset GBS disease

Answer 18

none

Question 19

Using intrapartum antibiotics has helped to reduce GBS, not does not help reduce the incidence of early onset sepsis in VLBW infants, however it has changed __________

Answer 19

the etiologic agents responsible for early onset sepsis

e.g., Gram-negative agents, e.g., E. coli are now the primary etiologic agents.