PRC assays allow rapid detection of group B streptococci during labourRapid detection of group B streptococci in pregnant women at delivery.

Duff, Patrick MD
Bergeron, MG
Ke, D
Menard, C
Picard, FJ
Gagon, M
Bernier, M
Quellette, M
Roy, PH
Marcoux, S
Fraser, WD

Professor and Residency Program Director; Department of Obstetrics and Gynecology; University of Florida, FL, USA

Abstracted from:Bergeron MG, Ke D, Menard C, Picard FJ, Gagon M, Bernier M, Quellette M, Roy PH, Marcoux S, Fraser WD. Rapid detection of group B streptococci in pregnant women at delivery. N Engl J Med 2000;343:175-179BergeronMGKeDMenardCPicardFJGagonMBernierMQuelletteMRoyPHMarcouxSFraserWDRapid detection of group B streptococci in pregnant women at delivery.N Engl J Med2000343175-179 .

Evidence-based Healthcare 5(1):p 24-25, March 2001.

BACKGROUND

Group B streptococcal infections are a leading cause of harm to newborn infants. 15-40% of pregnant women are infected. The standard culture method for diagnosis takes at least 36 hours.

OBJECTIVE

To establish the effectiveness of two polymerase-chain-reaction (PCR) assays for routine group B streptococci screening of women during delivery.

SETTING

Centre Hospitalier Universitaire de Quebec, Canada.

METHOD

Comparison of the results of specimen tests using three different agents.

LITERATURE REVIEW

No explicit strategy; 18 references.

PARTICIPANTS

One hundred and twelve pregnant women.

INTERVENTION

Anal, vaginal and combined anal and vaginal specimens were obtained and tested for group B streptococci using three methods during pregnancy and for 57 women before and after the amniotic membranes ruptured. Cultures were tested in a broth medium, conventional PCR assay and fluorogenic PCR assay.

OUTCOMES

Detection of group B streptococci.

MAIN RESULTS

Group B streptococci was identified in 33 pregnant women by culture and in 32 by the PCR assays (sensitivity 97%, 95% CI 82.5% to 99.8%; positive predictive value 100%; negative predictive 98.8%, 95% CI 92.3% to 99.9%). Sensitivity, specificity and positive and negative predictive value were all 100% prior to rupture but post rupture the PCR sensitivity fell to 93.8%. Results were delivered in 30-45 minutes by the fluorogenic PCR assay; 100 minutes by the conventional PCR assay; and at least 36 hours by the culture.

AUTHORS' CONCLUSIONS

PCR assays are reliable for the detection of group B streptococci in pregnant women and can be used both before and after membrane rupture during labour. Results arrive within 1-2 hours, can be done during labour and still allow time for intrapartum antibiotic prophylaxis.