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Are postnatal ampicillin levels actually related to the duration of intrapartum antibiotic prophylaxis prior to delivery? A pharmacokinetic study in 120 neonates
  1. Alberto Berardi1,
  2. Zaira Pietrangiolillo1,
  3. Maria Letizia Bacchi Reggiani2,
  4. Valentina Bianco1,
  5. Daniela Gallesi3,
  6. Katia Rossi1,
  7. Fabio Facchinetti4,
  8. Fabrizio Ferrari1
  1. 1Unit Operativa di Terapia Intensiva Neonatale, Dipartimento Integrato Materno Infantile, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
  2. 2Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Azienda Ospedaliero-Universitaria S.Orsola-Malpighi, Bologna, Italy
  3. 3Unità di Tossicologia e Farmacologia Clinica, Dipartimento di Medicina Diagnostica, Clinica e Sanità Pubblica, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
  4. 4Unità Operativa di Ostetricia, Dipartimento Integrato Materno Infantile, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy
  1. Correspondence to Dr Alberto Berardi, Unità Operativa di Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria Policlinico, Via del Pozzo, 71 -41124 Modena, Italy; berardi.alberto{at}policlinico.mo.it

Abstract

Objective To assess ampicillin levels according to the duration of intrapartum antibiotic prophylaxis (IAP).

Design Prospective cohort single-centre study.

Setting Tertiary care centre (Modena, Italy).

Patients 120 neonates≥35 weeks’ gestation exposed to IAP.

Interventions Neonates were divided into four groups, according to the duration of IAP prior to delivery: group 1 (n=30; <1 hour), group 2 (n=30; ≥1 and <2 hours), group 3 (n=30; ≥2 and <4 hours) and group 4 (n=30; ≥2 doses, ≥4 hours).

Main outcome measures Blood samples were collected at delivery (from the umbilical cord) and at age 4 hours (from a peripheral vessel).

Results Median duration of IAP was 121 min (range 7–2045 min). Median ampicillin levels in umbilical cord blood were 10.4 µg/mL (IQR 6.4–14.9) and in peripheral blood were 4.7 µg/mL (IQR 2.8–6.4µg/mL). Umbilical cord blood levels reached a peak approximately 30 min after IAP and then declined significantly (p<0.001). Peripheral blood levels did not differ among study groups. Neonates exposed to a full loading dose (n=115) had peripheral blood levels 2.5–70 times higher than the minimal inhibitory concentration for group B streptococcus. There was no relationship between neonatal ampicillin concentrations and the duration of IAP prior to delivery (β=−0.0003, 95% CI −0.02 to 0.001, p=0.680).

Conclusions Ampicillin levels reach a peak in the umbilical cord blood within 30 min of intrapartum administration. After a full loading dose, bactericidal levels persist for at least 4 hours after birth and seem independent of the duration of IAP prior to delivery.

  • Group B Streptococcus
  • Intrapartum antibiotic prophylaxis
  • Early-onset sepsis
  • Newborn

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Footnotes

  • Contributor All authors made substantive intellectual contributions to the published study and approved the final manuscript as submitted. AB and ZP designed the study and drafted the initial manuscript. MLBR and DG carried out the initial analyses, reviewed and revised the manuscript. KR and VB designed the data collection instrument, coordinated and supervised data collection and critically reviewed the manuscript. FFa and FFe conceptualised and designed the study, reviewed and revised the manuscript.

  • Contributors None.

  • Competing interests None declared.

  • Ethics approval The study protocol was approved by the ethical committee of the Azienda Ospedaliero-Universitaria of Modena (Italy) on 8 November 2013 (Protocol no 159/13).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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