Neonatal sepsis and death caused by resistant Escherichia coli: possible consequences of extended maternal ampicillin administration.

OBJECTIVE: Our goal was to evaluate the relationship between neonatal death caused by sepsis associated with ampicillin-resistant organisms and length of antibiotic exposure.

STUDY DESIGN: All neonatal deaths from culture-positive sepsis over a 3-year period were examined. Infants who were delivered at either the University of Mississippi Medical Center or at Saint Barnabas Medical Center at >/=24 weeks' gestation and died within 7 days of life were included. Information on the organism causing sepsis and its sensitivities was collected, and the number of doses of ampicillin administered to the mother before delivery was determined.

RESULTS: Of the 78 neonatal deaths, 35 met the inclusion criteria. There were 8 cases of sepsis from ampicillin-resistant Escherichia coli and 27 cases caused by other organisms. There was a statistically significant difference between the mean number of doses of ampicillin received by the ampicillin-resistant Escherichia coli group (17.6 +/- 5.5) compared with the other organisms group (4.9 +/- 3.6) (P <.001).

CONCLUSION: A relationship exists between neonatal death caused by ampicillin-resistant Escherichia coli and prolonged antepartum exposure to ampicillin.