[The influence of intrapartum antibiotic therapy on the diagnosis of early-onset neonatal sepsis].
OBJECTIVE
To determine the influence of intrapartum antibiotic therapy on blood and secretion cultures of newborn infants suspected of early-onset sepsis.


METHODS
From August 1995 through July 1996, 69 sequential newborn infants with early-onset sepsis or septic syndrome were included in the study. All of them were followed for the end point: positivity of blood, urine, CSF, tracheal secretion or umbilical catheter cultures. The sample size was figured out to be 17 for each group, for a significant level of 5%.


RESULTS
Seventeen mothers were treated with antibiotic. Ampicillin alone or in association with other drugs was utilized in 70% of them. Urinary tract infection occurred in 9 mothers (53%), ammonites in 6, one mother had both and another one had erysipelas. Thirteen newborn infants had positive cultures in the group whose the mothers had not received antibiotic (n=52), none of the 17 newborn infants delivered by the mothers treated with antibiotic had any positive culture (p=0.0164). The relative risk of positive culture in a septic neonate if the mother is not treated with antibiotic is 12 times higher than if the mother is treated with antibiotic.


CONCLUSIONS
The use of intrapartum antibiotic in newborn infants with early-onset sepsis or septic syndrome may cause a negativity of cultural exams, increasing the difficulty of the diagnosis of early-onset neonatal sepsis.
Vieira
R C
RC
Médica Neonatologista do Hospital de Clínicas de Porto Alegre.
Procianoy
R S
RS
Mulle
L D
LD
Prado
C H
CH