1 Screening van Zwangeren op Groep B Streptokokken. W.B.A. Mei 2003 L. Mahieu, Dienst Neonatologie,...

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Screening van Zwangeren op Groep B Streptokokken.

W.B.A. Mei 2003

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Inhoud

• Epidemiologie

• Microbiologie

• Kliniek

• Pathogenese

• Preventie mogelijkheden

• Toestand in Vlaanderen

• Richtlijnen

3

The Disease - USA• GBS emerged as an important pathogen in the

1970s

• Leading cause of sepsis in neonates

• Incidence: 0.4-4/1000. (Belgium= 2/1000)

• Motality > 14%

• Belgium: – 240 cases/year– 48 deads/ year

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Comparison with other Killers in Childhood.

• Meningococcal Invasive Disease– Incidence 2.3/100.000 children– Dead 0.2/100.000 children

• Road Accidents– Incidence 2.5 deads/ 100.000 children

• GBS invasive disease– Incidence 220/ 100.000 newborns– Deads 33/100.000 newborns

Neonatal GBS is an underestimated Public Health Problem.

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Invasive GBS Disease Incidence by Age Group and

Race

0.1

1

10

100

1000

Age group

Whites Blacks

MMWR Vol. 41 (No. SS-6) 1992

6

GBS Disease in Infants

0102030405060708090

< 1wk

1-3wk

1 2 3 4 5 6 7 8 9 10 11

Age (months)

Per

cen

t of

cas

es

A Schuchat. Clin Micro Rev 1998;11:497-513.

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Early-Onset Neonatal GBS Disease

0102030405060708090

0 1 2 3 4 5 6

Age (days)

Per

cen

t of

cas

es

A Schuchat. Clin Micro Rev 1998;11:497-513.

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Clinical Manifestations of Group B Streptococcus Infection

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Early-Onset Infection• < 6 days of life

• 85% :within 24 hours of birth

• case:fatality ratio 5-10%

low 5 min Apgar, shock, neutropenia, pleural effusion, apnea, delay treatment, low birth weight, prematurity

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• 25-40%

• respiratory signs = initial clinical findings

(apnea, grunting respirations, tachypnea, cyanosis)

• hypotension

• associated signs: – lethargy, poor feeding, hypothermia or fever,

abdominal distention, pallor, tachycardia, jaundice

Early-Onset Infectionbacteremia without focus

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• 5-10%, especially serotype III strains

• clinical presentation ~ bacteremia

• most common sign = Convulsions

THUS: CSF !!

• persistent seizures, (semi)coma

= poor prognosis

Early-Onset Infectionmeningitis

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• 35 - 55%• acute respiratory signs: grunting, tachypnea, apnea• often at birth, most < 24h• low Apgar (<5 at 1min)• X-ray abnormalities:

– > 50% HMD– 30% infiltrates– occasionally absent (~ persistent fetal circulation)

Early-Onset Infectionpneumonia

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• Profound progressive hypoxemia that is usually out of proportion to the radiographic evidence of pulmonary disease

Early-Onset Infectionpersistent fetal circulation

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Early-Onset Infectionpneumonia

15

17

18

• 7 days - 12 weeks postnatal age

• case:fatality ratio 2-6%

• serotype III strains

• “clusters” in NICU (~ early onset)

• manifestations:– meningitis– bacteremia without focus– focal: osteomyelitis, septic arthritis, cellulitis, adenitis

Late-Onset Infection

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Late-Onset Infectionosteomyelitis / septic arthritis

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• low incidence, high morbidity disease

• EOS = Pneumonia PFC hypoxia death

• LOS = Meningitis

GBS DiseaseBig Disease with a Little Name

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Maternal to Infant TransmissionGBS colonized mother

Non-colonized newborn

Colonized newborn

Asymptomatic Early-onset sepsis, pneumonia, meningitis

50% 50%

98% 2%

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

Risk Factors

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• GBS strain virulence• Genital inoculum• GBS bacteriuria• Delivery <37 weeks’ gestation• Premature rupture of membranes• Rupture of membranes >18 hours• Low levels of CPS-specific IgG• Complement component deficiency• Immature WBC function

Early-Onset Infectionrisk factors

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GBS Maternal Colonization

• GBS Carriers– 10% - 30% of women (Belgium= 13-25%)– higher in African Americans and nonsmokers– clinical signs not predictive (Asymptomatic)– dynamic condition

• When to culture?– culture at delivery -- too late– prenatal cultures predict delivery status

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Prevention with Antibiotics

• WHEN are antibiotics most effective?– Antenatal– Postnatal– Intrapartum

• WHO should receive antibiotics ?– GBS carriers– OB risk factors– GBS carriers with OB risk factors

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Consensus Guidelines

• Key Issues– predictive value of prenatal cultures– culture methods– disease in the asymptomatic carrier– risk stratification of women– cost-effectiveness

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GBS Screening

WHEN ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Predictive Value of Antenatal Cultures by Interval to

Delivery

0

20

40

60

80

100

120

6 5 4 3 2 1

Weeks before delivery

Per

cent

PPV NPV

N=826; 26.5% GBS carriersYancey et al., OB GYN 1996;88:811-5.

>

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Sensitivity and Specificity of Late Antenatal Cultures

43

898597

0

20

40

60

80

100

120

6 1-5

Weeks before delivery

Per

cent

sensitivity specificity

>

N=826Yancey et al., OB GYN 1996;88:811-5.

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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GBS screening

WHERE ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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GBS Carriage by Culture Site

Women instudy (#)

Vagina (%) Anorectum (%) Both (%)

789 10 18 21*

94 18 28 31*

301 11 14 18*

* P <0.05 both vs. vaginal only

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Specimen technique

• Lower vagina + Rectum (through anal sphincter)– One swab

– Without speculum

– Out patient setting or patient herself

• Transport– non-nutritive medium (Amies, Stuart’s without

charcoal)

– Store at room t° or in fridge (max. 48h)

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GBS culture

HOW ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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GBS Carriage by Culture Method

Women instudy (#)

Selectivebroth (%)

Blood agarplate (%)

166 34 14*

952 17 9*

383 20 13*

* P <0.05 selective broth vs. blood agar

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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What is ‘Selective Broth Medium’?

• 1. Incubatie overnight on 35-37°C:– Todd-Hewitt broth supplemented with:

• nalidixic acid (15 mg/L) and colistin (10 mg/L)

– Appropriate media are commercially available (e.g. LIM broth [BD])

• 2. Subculture 18-24h:– Granada medium agar (Biomedics, Spain or

distr. by International Medical)• (anaerobically or glass coverslip)

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Granada mediumOrange colonies

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Is Intrapartum Screening an Alternative?

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Intrapartum screening

• Sensitivity should be > 85% (= culture)

• Rapid

• Covenient for laboratory– 24h a day– 7 days a week

• Alternatives

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Intrapartum GBS Screening- Intrapartum GBS Screening- AlternativesAlternatives

• GBS antigen test.– Sensitivity to low

(65%)

– Positive= heavy colonization.

– Negative = Unknown colonization.

• Real time PCR.– Sensitivity 97%,

– Specificity 96.9%

– 45 min. Maximum

– Not available on 24h basis

– Not available in every Lab.

At Present No Good Alternative

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Communication

• To laboratory;– Clearly request “GBS screening”– Expected site of delivery– Expected time of delivery

• To Clinician; – address of expected delivery (Fax?) – Physician’s office.– Report only QUALITATIVE (Positive or Negative)

45

GBS screeningGBS screening

WHO ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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CDC’s Prevention Recommendations 1996

PICK EITHER APPROACH:

Screening-based approach

• 35-37 wk culture, offer IAP to preterm and to GBS carriers

Risk-based approach

• IAP to preterm, ROM > 18 h, or intrapartum fever (T > 38 C)

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Prevention Strategy Using Risk-Based Approach

Any of the following:• Delivery < 37 wks gestation*• ROM > 18 hrs• Intrapartum temp > 38C (100.4 F)• Previous infant w/GBS disease• GBS bacteriuria this pregnancy

Give intrapartum penicillin

No intrapartum antibiotics

YES

NO

* For ROM w/out labor at <37 wks, collect GBS culture and EITHER:• treat until cultures complete and negative• or begin treatment once positive culture results available

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Obstetric Risk Factors Among Women with GBS Infants

54%

46%

* obstetric risk factors

* no obstetric risk factors

n = 245

* premature < 37 wk, ROM > 18 hr, temp > 100.4 F (38 C)

Rosenstein N. OB GYN 1997;90:901-6.

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Rates of Early-Onset GBS Disease by Rates of Early-Onset GBS Disease by Prenatal Colonization & Risk FactorsPrenatal Colonization & Risk Factors

40.8

5.10.9 0.3

0

5

10

15

20

25

30

35

40

45

Col+,RF+ Col+,RF- Col-,RF+ Col-,RF-

Cas

es p

er 1

000

live

bir

ths

Col: prenatal vag/rect cultureRF: risk factors (gest. <37 wks, ROM >12 hr, fever > 37.5 C)

Boyer & Gotoff, Antibiot Chemother 1985.

51

Advantages of the Risk-Based Strategy

• Logistically easier

• Potentially less expensive

• Particularly applicable to settings with low prenatal care

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Prevention Strategy Using Screening-Based Approach

Risk factors:• Previous infant w/GBS disease• GBS bacteriuria this pregnancy• Delivery < 37 wks gestation

Collect rectal & vaginal swab at 35-37 wks

No intrapartum prophylaxis needed

Risk factors:• Intrapartum fever > 38C• ROM > 18 hrs

Give intrapartum penicillin

Offer intrapartum penicillin

Give intrapartum penicillin

YES

NO

NO

GBS-

GBS+

YES

Not done, incomplete, or results unknown

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Advantages of the Screening-Based Strategy

• Optimizes prenatal screening– fewer false negatives– less pressure on physicians to treat

• Antibiotics to all GBS carriers– antibiotics start earlier before development of

risk factors– adequate time for antibiotic effectiveness

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Comparison of Prevention Strategies

Prevention Strategy EO GBS casesprevented (%)

Deliveries receivingIAP (%)

Cost compared to nostrategy (%)

Screening-based:35-37 wk screen/IAPfor preterm and GBScarriers

86.0 26.7 43.7

Risk-based:no screen/IAP for allwith risk factors*

68.8 18.3 35.6

* fever, ROM > 12 hr, gestation < 37 wks

Rouse et al., OB GYN 1994;83:483-94.

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Potential Impact of Each Strategy

0

0.5

1

1.5

2

2.5

1989 1990 1991 1992 1993 1994 1995 1996

Year

Cas

es p

er 1

000

live

birt

hs

Early-onset GBS disease by Year, Area A

Screening-BasedApproach

Risk-BasedApproach

Rosenstein N, et al., OB GYN 1997;90:901-6.

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GBS chemoprophylaxis

WHEN to Start ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Timing of Intrapartum Ampicillin and Transmission of

GBSInterval between

ampicillin and birthNo. of GBS carrier

mothersNo. (%) GBS

colonized babiesControls

(no ampicillin)209 98 (47)

< 1 hour 30 13 (43)

1-2 hours 36 7 (19)

2-4 hours 80 2 (2.4)

>4 hours 105 1 (0.9)

De Cueto et al., OB GYN 1998;91:112-4.

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GBS chemoprophylaxis

What to Start ?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

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Antimicrobial Resistance in Antimicrobial Resistance in Belgium.Belgium.

-lactams (Pen, Amp, Cephalo-I) : – Today 100 % Sensitive!

Erythromycine & Clindamycine– Belgium : 10 à 20 % in 2001– 88 % type MLS (20 % inducable)

P. Melin (ULG)

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Intrapartum Prophylaxis

• Penicillin G– 5 million units IV load, then 2.5 million units

IV every 4h until delivery

• Ampicillin– 2 g IV load, then 1g IV every 4h until delivery – acceptable alternative, but broader spectrum

may select for resistant organisms

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• Penicillin “allergic”– History = 12%

– Proven peni-allergy is only 1-2%

• Alternative drugs:– No anaphylaxic history: cephalosporins 1st. Gen.

(cephazolin)• Loading: 2g, then 1g IV Q8h

– Clindamycin (Dalacin)• 900 mg Q8h

– Vancomycin (Vancocin) in Clinda-R organisms?

Intrapartum Prophylaxis

Efficacy of these drugs NOT proven !

64

Impact of

Prevention?

65

Incidence of GBS Disease and Hospital Prevention Policy

1.8

1.5

0.7

0.90.8

0.70.6

0

0.20.4

0.6

0.81

1.2

1.4

1.61.8

2

TN GA MN OR MD CA CT

Cas

es p

er 1

000

live

bir

ths

30

48 50

6256

71

83

0

10

20

30

40

50

60

70

80

90

TN GA MN OR MD CA CT

Cas

es p

er 1

000

live

bir

ths

Rate of Early-OnsetGroup B Streptococcal Disease

By Surveillance Site in 1996

Percent of Hospitals with aGroup B Streptococcal

Prevention Policy in 1996

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Early-Onset GBS Disease by Year and Location

Active Surveillance (190,000 births/year)

0

0.5

1

1.5

2

2.5

SF MD Atlanta TN Total

Cas

es p

er 1

000

live

bir

ths

1993 1994 1995 1996 1997

MMWR 1997;46 (No. 21):473-77.

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What we Think

is NOT

What we Do !

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Flemish Obstetricians’ profile Flemish Obstetricians’ profile in 1999in 1999

- A Survey.- A Survey.

L.MahieuL.Mahieu et al, 2000, J Obst Gyn;5:460-4 et al, 2000, J Obst Gyn;5:460-4

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Survey - ObjectiveSurvey - Objective

– Flemish obstetricians’ attitude regarding the prevention of perinatal GBS.

– To determine the physician characteristics that predict divergent opinions from the screening based approach

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• Mailing list (VVOG)• Anonymous survey:

– 4 pages– 5 min.– Dichotomized questions (yes/no)– Items: screening, prophylaxis, demografic

• Send ones• Pre-stamped envelope

Survey - MethodsSurvey - Methods

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ResultsResultsDemografic CharacteristicsDemografic Characteristics

• Surveys returned by 310 (53%) of 582

• Age: 40 (25-79) years

• Gender: 62% male

• No. of deliveries: 153 (10-500) / year

• Hospital: 18% university, 64% non-academic, 18% rural

• Obstetrical interests: 61%

• Group practice: 56%

73

• Never (4.2%):– No consensus– Does not influence AB prophylaxis

• Always (44%):– Indication for AB therapy– Negative experience– Routine

• If “risk factor” (52%):– PPROM– previous child GBS+

ResultsResultsScreening - Screening - Who?Who?

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ResultsResultsScreening - Screening - Where?Where?

0

5

10

15

20

25

30

35

40%

Cervix Vagina Vagina +Rectum

Cervix +Introitusvaginae

76

ResultsResultsScreening - Screening - When?When?

0

10

20

30

40

50

60

70

80%

26-28w 28-34w 35-37w intralabour

77

ResultsResultsProphylaxis - Prophylaxis - When?When?

0

10

20

30

40

50

60

70

80%

OnsetLabour

BeforeLabour

BeforePartus

OnsetPartus

AfterPartus

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ResultsResultsProphylaxis - Prophylaxis - What?What?

52

24 22

0,3 1,3

0

10

20

30

40

50

60

%

Ampicillin Amoxi-Clav Penicillin Clindamycin Other AB

80

9.86

9.648.227.63 9.09

Independent Demographic Predictors of Independent Demographic Predictors of Compliance to CDC Guidelines (*)Compliance to CDC Guidelines (*)

81

0

2

4

6

8

10

12

2 3 4 5 6 7

Leeftijd van de verloskundige (decaden)

Gem

idd

eld

e S

co

reIndependent Demographic Predictors of Independent Demographic Predictors of

Compliance to CDC Guidelines (*)Compliance to CDC Guidelines (*)

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• Minority (44%) believe in routine prenatal GBS screening.

• 1/3 screen at cervix.

• 3/4 use broadspectrum AB (ampi, +/- clavulanic acid).

• Compliance to guidelines is influenced by:– province (E- & W-Flanders)– High age of Obstetrician

ConclusionsConclusionsPriorities for Improvement?Priorities for Improvement?

84

Managment of the Neonate at Risk for GBS.

85

The Symptomatic Neonate• Full diagnostic evaluation

– FBC + differential– CRP– Culture blood– Culture CSF (if indicated)– Endotracheal cultures (ventilated infant)– Surface cultures (nose and/or ear)

• Start antibiotics: Ampicillin + AG.– 10 days for sepsis, 14 days for meningitis, 28 days for ventriculitis,

osteomyletis– AG stop after 3-5 days.

86

Asymptomatic Newborn at Risk.

• Limited evaluation if– Duration of IAP < 4h (< 2 doses)– Optimal IAP but Gestation < 35 weeks

• Serial measurement at birth, 12h and/or 24h – FBC– CRP– No cultures unless AB treatment is started.

87

Laboratory Indices for EOS.

LimitsNeutrophil

0H 6H 12H 18H 24H

LOW 1800 5400 8000 8000 7200

HIGH 7000 13000 14400 13000 12500

CRP > 1.4 mg/dL or Increase (X 2-4).

Leucopenia < 5000/mm³

88

Sample Algorithm for Management of Newborn if Maternal IAP

Maternal IAP for GBS?

• Full diagnostics evaluation• Empiric therapy

yesSigns/sx of sepsis in newborn?

Gestational age

Duration of maternal IAP before delivery

• No evaluation• No therapy• Observe at least 48 hrs

no

35 wks+

>4 hrs or >2 doses

< 4 hrs or< 2 doses

• Limited evaluation• Observe at least 48 hrs• If sepsis suspected, full diagnostic evaluation and empiric therapy

< 35 wks

89

Adjuvant Treatment

• IV Immunoglobulines?– opsonisation

• Cytokines?– GM-CSF– G-CSF

• Surfactant?– SP-A

• NO

90

Hoge Gezondheidsraad-2003Ministerie van Volksgezondheid en

Leefmilieu

Microbilogist:• Mellin P.• Claeys G.• Naessens A.•Hubinon C.

Gynecologists:• De Mol P.• Donders G.• Temmerman M.• Beckstedde I.• Foulon W.•Van Eldere J.

Pediatricians:• Mahieu L.• Tuerlinckx D• Levy J• Lepage P.

Ministery: DeVleeschouwer G./ Dubois J.

91

Need for Continuous Medical

Education

and

development ofWritten Guidelines

L. Mahieu et al. Obstet. Gynecol. 2000; 20: 460-464

92

Evaluating Prevention Programs

• Consider developing surveillance for:– Neonatal GBS disease?– Adverse reactions to prophylaxis?– Emergence of resistant perinatal infections?

• Economic evaluation?

• Compliance to guidelines?

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen

93

Perinatale GBS.

Beter voorkomen.

Dan genezen !

L. Mahieu, Dienst Neonatologie, U. Z. AntwerpenL. Mahieu, Dienst Neonatologie, U. Z. Antwerpen