Download Administrative Office St. Joseph`s Hospital Site, L301

Administrative Office
St. Joseph's Hospital Site, L301-10
50 Charlton Avenue East
HAMILTON, Ontario, CANADA L8N 4A6
PHONE: (905) 521-6141
FAX: (905) 521-6142
http://www.fhs.mcmaster.ca/hrlmp/
Issue No. 48
QUARTERLY NEWSLETTER
July, 1999
SCREENING FOR GROUP B STREPTOCOCCI IN
PREGNANCY
Introduction: Group B streptococci (GBS) frequently colonize the anogenital tracts of women, and are a
leading cause of neonatal sepsis and meningitis (1-4 cases per 1,000 live births). 1-2% of babies born to
colonized mothers will develop disease, usually in the setting of premature birth, prolonged rupture of
membranes, or maternal fever. Screening pregnant women for GBS during pregnancy, and treating high-risk
pregnancies at the time of delivery, reduces colonization and infection rates in infants, and may reduce
mortality.
Prevention of Neonatal GBS Infection: There are two approaches to reducing GBS-related neonatal
sepsis: universal treatment of high-risk pregnancies without considering GBS status; or universal screening
at 35-37 weeks and treatment of all GBS-colonized women. No one strategy is clearly superior. As
colonization can be intermittent, screening earlier in pregnancy is not recommended. Antibiotic treatment
during pregnancy does not eradicate GBS colonization; rather, treatment is given intra-partum.
Laboratory Specimens: If screening is undertaken, the laboratory needs to have the appropriate
specimens submitted at the appropriate time. Group B Streptococcal screening must be clearly requested.
Please specify SOURCE of swab, and "PREGNANCY: GROUP B STREP" on the requisition. We
recommend a single combined recto-vaginal swab, taken at 35-37 weeks. Separate swabs should be taken,
if required, for other pathogens. We are striving to improve the sensitivity of our laboratory methods for
detecting Group B Streptococci, and results are available in 24-72 hours. Satisfactory rapid tests for use in
labour are not available.
What swab does what: There may be some confusion regarding the optimal swab for screening and
diagnosis of genital infections in pregnancy. (See table below.) Investigation for other pathogens may be
indicated in certain clinical settings (STD’s, wound infections). Please consult the Microbiology Laboratory
for non-routine requests.
Specimen
Routine processing
On Request
Vaginal
Direct exam for:
Bacterial Vaginosis, Candida species, Trichomonas
vaginalis
Group B Streptococcus
(pregnancy only)
Cervical
Neisseria gonorrhoeae
Chlamydia trachomatis
(special swab, transport
media)
Rectovaginal
Group B Streptococcus
(pregnancy only)
Summary: Ensure that vaginal, cervical, and recto-vaginal swabs are taken as indicated for the pathogens
sought. For GBS screening in pregnancy, a single recto-vaginal swab at 35-37 weeks for group B
Streptococcal culture is recommended. Please clearly label the source of specimen and request for GBS
culture.
Written by: Drs. Marek Smieja, David Groves, Fiona Smaill. For comments or questions call MS or FS at
521-2100 extension 6307 or DG at 522-1155 extension 5016.
References:
Maternal/Fetal Medicine Committee (SOGC). Policy Statement. Statement on the prevention of early-onset
Group B Streptococcal infections in the newborn. Journal Soc Obstet Gynaecol Can 1997; 19: 751-758.
Group B Streptococcal Infections. In: Red Book: Report of the Committee on Infectious Diseases. 24 th
Edition. Elk Grove Village, IL: American Academy of Pediatrics; 1997: 496-501.
Centers for Disease Control and Prevention. Prevention of perinatal group B streptococcal disease: a public
health perspective. MMWR 1996; 45(No RR-7):X
Smaill F. Intrapartum antibiotics for Group B streptococcal colonization. In: The Cochrane Library. Update
software 1998, Issue 1.
The Hamilton Regional Laboratory Medicine Program is a collaborative program of the Hamilton Health
Sciences Corporation, St. Joseph's Hospital and McMaster University.
For further information concerning the Hamilton Regional Laboratory Medicine Program contact Mrs. Sue
Friend at (905) 521-6141.
For information on Community Laboratory Services please contact Mrs. Kathy Tiers (905) 521-6052, or the
Laboratory Reference Centre contact Mrs. Barb Baltzer at (905) 521-6065 or fax to (905) 528-1464.