title: Efficacy of intrapartum chemoprophylaxis less than 4 hours duration.
abstract: OBJECTIVE
  Current guidelines for prevention of group B streptococcus (GBS) early-onset infection recommend to administer antibiotic during labor at least 4 h prior to delivery (adequate prophylaxis). We aimed to determine if neonatal GBS colonization may be significantly decreased in case of inadequate (<4 h) duration of ampicillin prophylaxis.
  
  
  METHODS
  In prospective, cohort study, 167 infants born to 167 GBS culture-positive mothers without additional risk factors were enrolled. Cultures were collected both, at 10-24 h after birth (admission) and at discharge.
  
  
  RESULTS
  Among 137 infants born to mothers who received inadequate prophylaxis, 5 (3.6%, C.I. = 0.5-6.8) were colonized (≥1 sites) at admission, at discharge, or both, at admission and discharge. Eighty-two women received prophylaxis <2 h before delivery and two infants (2.4%) were colonized at discharge. Eighteen (60.0%, C.I. = 42.5-77.5) of 30 infants who were not exposed to prophylaxis were colonized at admission or both, at admission and discharge. Colonization was significantly more frequent among infants born to untreated mothers with respect to infants born to women who received inadequate prophylaxis (either <2 or <4 h).
  
  
  CONCLUSIONS
  In this selected group, inadequate prophylaxis significantly interrupted vertical colonization. This effect was evident even if prophylaxis started <2 h before delivery.
authors.affiliation: Unità Operativa di Neonatologia, Azienda Ospedaliero-Universitaria Policlinico di Modena, Italy. berardi.alberto@policlinico.mo.it
authors.forename: Alberto
authors.initials: A
authors.lastname: Berardi
authors.forename: Cecilia
authors.initials: C
authors.lastname: Rossi
authors.forename: Augusto
authors.initials: A
authors.lastname: Biasini
authors.forename: Simona
authors.initials: S
authors.lastname: Minniti
authors.forename: Claudia
authors.initials: C
authors.lastname: Venturelli
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Ferrari
authors.forename: Fabio
authors.initials: F
authors.lastname: Facchinetti
mesh_terms: D000667:Ampicillin / Q000008:administration & dosage; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control* / Q000706:statistics & numerical data; D007743:Labor, Obstetric / Q000187:drug effects / Q000502:physiology; D036801:Parturition / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy*; D012307:Risk Factors; D013290:Streptococcal Infections / Q000151:congenital / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000667:Ampicillin