title: Intrapartum antibiotic prophylaxis and early-onset neonatal sepsis patterns.
abstract: OBJECTIVE
  To compare the relative effects of intrapartum antibiotic prophylaxis regimens on patterns of early-onset neonatal sepsis.
  
  
  METHODS
  We performed an historical cohort study of 17187 infants born at our center from September 1993 to February 2000. A risk-based strategy was employed prior to July 1996 and a screening-based strategy was utilized thereafter. Ampicillin was utilized prior to March 1995 and penicillin was used thereafter.
  
  
  RESULTS
  There were 75 cases of neonatal sepsis, 34 (4. 10/1000) in the risk-based era and 41 (4.63/1000) in the screening-based era (p = 0.62). There were fewer ampicillin-resistant isolates during the risk-based than the screening-based era (32 versus 61%; p = 0.014). The only significant change in organism-specific sepsis rates was an increase in the rate of infection caused by coagulase-negative staphylococci in the screening-based era (0.36 versus 1.46/1000; p = 0.018), but 75% of infants infected with these organisms were not exposed to beta-lactam antibiotics within 72 h prior to delivery. For the risk- and screening-based eras, respectively, the rates of Gram-negative sepsis (1.21 versus 1.46/1000; p = 0.65) and the proportions of Gram-negative pathogens that were ampicillin-resistant (70 versus 77%; p = 1.0) were similar. The drug employed for prophylaxis did not appear to affect the pattern of sepsis cases.
  
  
  CONCLUSIONS
  In our patient population, coagulase-negative staphylococci have become the most common cause of early-onset neonatal sepsis. The cause of this shift in pathogen prevalence is uncertain and seemingly unrelated to intrapartum antibiotic exposure.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Florida College of Medicine, Gainesville, FL 32610-0294, USA. edwardsr@obgyn.ufl.edu
authors.forename: Rodney K
authors.initials: RK
authors.lastname: Edwards
authors.forename: Whitney E
authors.initials: WE
authors.lastname: Jamie
authors.forename: Donald
authors.initials: D
authors.lastname: Sterner
authors.forename: Susan
authors.initials: S
authors.lastname: Gentry
authors.forename: Kathy
authors.initials: K
authors.lastname: Counts
authors.forename: Patrick
authors.initials: P
authors.lastname: Duff
mesh_terms: D000667:Ampicillin / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis; D016470:Bacteremia / Q000453:epidemiology / Q000517:prevention & control*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology / Q000517:prevention & control; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology / Q000517:prevention & control*; D011256:Pregnancy Outcome; D015995:Prevalence; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D013290:Streptococcal Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D013292:Streptococcus agalactiae / Q000187:drug effects*
chemical_list: D000667:Ampicillin