Changing patterns in neonatal Escherichia coli sepsis and ampicillin resistance in the era of intrapartum antibiotic prophylaxis.
OBJECTIVE
The goal was to determine current trends in Escherichia coli-related early- and late-onset sepsis and patterns of ampicillin resistance in relation to institutional changes in the use of intrapartum antibiotic prophylaxis.


METHODS
A retrospective review of data for all infants with E. coli sepsis at Yale-New Haven Hospital from 1979 to 2006 was performed. Study periods were based on predominant intrapartum antibiotic prophylaxis practices at Yale-New Haven Hospital, that is, (1) 1979 to 1992 (no formal intrapartum antibiotic prophylaxis), (2) 1993 to 1996 (risk factor-based), and (3) 1997 to 2006 (screening-based). Sepsis rates and patterns of ampicillin resistance were compared.


RESULTS
Fifty-three cases of E. coli early-onset sepsis and 129 cases of E. coli late-onset sepsis were identified over 3 eras. In very low birth weight (<1500 g) infants, increases in E. coli early-onset sepsis (period 1: 2.83 cases per 1000 very low birth weight admissions; period 2: 7.12 cases per 1000 very low birth weight admissions; period 3: 10.22 cases per 1000 very low birth weight admissions), intrapartum ampicillin exposure, and ampicillin-resistant E. coli were observed. Intrapartum ampicillin exposure was determined to be an independent risk factor for ampicillin-resistant E. coli early-onset sepsis. For the first time, a significant increase in E. coli late-onset sepsis was observed in preterm infants (period 1: 10.39 cases per 1000 very low birth weight admissions; period 2: 16.01 cases per 1000 very low birth weight admissions; period 3: 21.66 cases per 1000 very low birth weight admissions) and term infants (period 1: 4.07 cases per 1000 admissions; period 2: 4.22 cases per 1000 admissions; period 3: 8.23 cases per 1000 admissions).


CONCLUSIONS
Studies to provide a better understanding of potential consequences of intrapartum antibiotic exposure and its contribution to evolving trends in neonatal sepsis are urgently needed.
Bizzarro
Matthew J
MJ
Division of Perinatal Medicine, Department of Pediatrics, Yale University School of Medicine, 333 Cedar St, New Haven, CT 06520-8064, USA.
Dembry
Louise-Marie
LM
Baltimore
Robert S
RS
Gallagher
Patrick G
PG
D000667:Ampicillin / Q000008:administration & dosage*; D000668:Ampicillin Resistance; D019072:Antibiotic Prophylaxis / Q000379:methods*; D016470:Bacteremia / Q000188:drug therapy* / Q000401:mortality / Q000517:prevention & control / Q000635:transmission; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000401:mortality / Q000517:prevention & control / Q000635:transmission; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D011295:Prenatal Care / Q000379:methods; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D015996:Survival Rate
D000667:Ampicillin