Volume 129, Issue 1 p. 9-12
Clinical articles

Vaginal group B streptococcus status during intrapartum antibiotic prophylaxis

Santiago Scasso

Corresponding Author

Santiago Scasso

Department of Obstetrics and Gynecology, Pereira Rossell Hospital, University of Uruguay, Montevideo, Uruguay

Corresponding author at: Orleans 2273 CP 11500 Montevideo, Uruguay. Tel.: + 598 99277738; fax: + 598 26000434.Search for more papers by this author
Joel Laufer

Joel Laufer

Department of Obstetrics and Gynecology, Pereira Rossell Hospital, University of Uruguay, Montevideo, Uruguay

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Grisel Rodriguez

Grisel Rodriguez

Department of Microbiology, University of Uruguay, Montevideo, Uruguay

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Justo G. Alonso

Justo G. Alonso

Department of Obstetrics and Gynecology, Pereira Rossell Hospital, University of Uruguay, Montevideo, Uruguay

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Claudio G. Sosa

Claudio G. Sosa

Department of Obstetrics and Gynecology, Pereira Rossell Hospital, University of Uruguay, Montevideo, Uruguay

Department of Epidemiology, University of Uruguay, Montevideo, Uruguay

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First published: 18 December 2014
Citations: 27
Preliminary results were presented at the 10th World Congress of Perinatal Medicine; November 8–11, 2011; Punta del Este, Uruguay.

Abstract

Objective

To assess maternal group B streptococcus (GBS) colonization status and the pharmacokinetic profile of penicillin G in the umbilical cord and amniotic fluid compartment during 4 hours of intrapartum antibiotic prophylaxis (IAP).

Methods

In a prospective study at a hospital in Montevideo, Uruguay, 60 GBS carriers in active labor after a singleton pregnancy of 37 weeks or more were enrolled between April 1, 2011, and April 30, 2012. Intravenous penicillin G was administered via a standard regimen. Rectovaginal samples were obtained before IAP initiation, and 2 and 4 hours after the initial dose. Penicillin G concentrations were measured by high-performance liquid chromatography. Samples were obtained from fetal cord blood in all cases and from amniotic fluid obtained from patients who delivered by cesarean.

Results

Among the 60 participants, 43 (72%) had a positive rectovaginal sample before IAP initiation. Of these women, 23 (53%) had negative cultures after 2 hours; after 4 hours, only 5 (12%) remained positive for GBS. The penicillin G concentration in amniotic fluid and cord blood was above the minimum inhibitory concentration (0.12 μg/mL) in all cases.

Conclusion

Four hours of IAP was needed to reduce the number of women with positive GBS cultures to 12%. Therefore, 4 hours of IAP might be necessary to achieve overall effectiveness from this treatment.