Published Date: 1997-09-29 23:50:00
Subject: PRO> Strep. Group B, perinatal infection - USA
Archive Number: 19970929.2059

STREPTOCOCCUS GROUP B, PERINATAL INFECTION - USA
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A ProMED-mail post
Date: Sun, 28 Sep 1997 22:25:34 +2700
From: Edward Schroder <schroder@usa.healthnet.org>
September 28, 1997
Today at the Interscience Conference on Antimicrobial Agents and
Chemotherapy (ICAAC) in Toronto, Canada, Dr. Ann Schuchat, Acting Chief
of the Respiratory Diseases Branch at CDC, Atlanta, reported on progress
toward control of life-threatening Group B _Streptococcus_ infections of
neonates.
For the last two years the consensus recommendations of CDC
have included a recommendation that evaluations of maternal risk factors
or culture screening between 35-37 weeks of gestation be used to assess
the likelihood of maternal/fetal transfer of Group B _Streptococcus_ sp.
She reported that between 10% and 30% of pregnant women may be colonized
(G.I. or vagina) with Group B _Streptococcus_ sp. Fifty percent of
infants delivered by colonized women will be colonized by the organism,
with a resulting disease incidence of 2/100 for colonized infants, and a
case fatality rate of 4%.
The CDC has organized a multi-center study to enhance understanding of
the predictive value of prenatal culture procedures, and the potential
benefit of antibiotic prophylaxis for culture-positive women, or those
in high risk groups (African-American women have a higher carriage rate
than do others in the US). Dr Schuchat also indicated that capsular
polysaccharide serotype prevalence has shifted from types 1, 2, and 3
during the 1970s to a increasing prevalence of type 5 in the 1990s.
Dr Sharon Hillier, from the Department of Obstetrics and Gynocology at
the University of Pittsburgh School of Medicine, reported a strong
correlation between heavy colonization of pregnant women by Group B
_Streptococcus_ sp. and delivery of premature or low-birth-weight
infants. This conclusion is based on cultures of several thousand
placentas, which showed an overall rate of infection by Group B
_Streptococcus_ of 0.5%.
A positive placental culture was twice as likely
to be derived from delivery of a premature, low-birth-weight child than
was an uninfected placenta. She indicated that much of the fetal
colonization occurs prior to passage through the birth canal, and that
infection of placental tissues was of particular significance in
predicting outcome for the infant.
Dr Hillier has data suggesting that "intra-partum" prophylaxis (usually
with penicillin) reduces the incidence of maternal bacteremia among
heavily colonized women. As yet, neither Dr Schuchat nor Dr. Hillier
have convincing evidence that antibiotic prophylaxis had a significant
impact on infant morbidity and mortality. There is concern among
investigators about the potential for increased antibiotic resistance
that could result from widespread prophylaxis.
--
E. Schroder
ProMED-mail
<schroder@usa.healthnet.org>
[Ed, our new Managing Editor, is presently acting as ProMED-mail's roving
reporter in Toronto - Mod.JW]
....................................................jw
--
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