title: Effect of antibiotic use on antimicrobial antibiotic resistance and late-onset neonatal infections over 25 years in an Australian tertiary neonatal unit.
abstract: BACKGROUND
  Antibiotic resistance is a worldwide problem. We describe 25 years of responsible antibiotic use in a tertiary neonatal unit.
  
  
  METHODS
  Data on neonatal infections and antibiotic use were collected prospectively from 1990 to 2014 at a single tertiary Sydney neonatal intensive care unit attached to a maternity unit. There are approximately 5500 deliveries and 900 nursery admissions per year.
  
  
  RESULTS
  The mean annual rate of late-onset sepsis was 1.64 episodes per 100 admissions. The mean number of late-onset sepsis episodes per admission to the neonatal unit decreased by 4.0% per year (95% CI 2.6% to 5.4%; p<0.0001) and occurred particularly in infants born weighing <1500 g. No infants with negative cultures relapsed with sepsis when antibiotics were stopped after 48-72 hours. Antibiotic use decreased with time. The proportion of colonising methicillin-resistantStaphylococcus aureusisolates decreased by 7.4% per year (95% CI 0.2% to 14.1%; p=0.043). The proportion of colonising Gram-negative bacilli isolates resistant to either third-generation cephalosporins or gentamicin increased by 2.9% per year (95% CI 1.0% to 4.9%; p=0.0035). Most were cephalosporin-resistant; gentamicin resistance was rare. An average of one baby per year died from late-onset sepsis, the rate not varying significantly over time. The mortality from episodes of late-onset sepsis was 25 of 332 (7.5%).
  
  
  CONCLUSIONS
  Stopping antibiotics after 2-3 days if neonatal systemic cultures are negative is safe. However, it does not prevent the emergence of cephalosporin-resistant Gram-negative organisms.
authors.affiliation: Junior Medical Staff Unit, Royal North Shore Hospital, St Leonards, New South Wales, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Carr
authors.affiliation: NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Elizabeth Helen
authors.initials: EH
authors.lastname: Barnes
authors.affiliation: RPA Newborn Care, John Spence Neonatal Nursery, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.|Discipline of Obstetrics, Gynaecology and Neonatology, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Gordon
authors.affiliation: Discipline of Child Health, University of Sydney, Sydney, New South Wales, Australia.|Department of Infectious Diseases & Microbiology, Children's Hospital at Westmead, Westmead, New South Wales, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Isaacs
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001424:Bacterial Infections / Q000188:drug therapy* / Q000453:epidemiology; D004334:Drug Administration Schedule; D004352:Drug Resistance, Microbial; D004363:Drug Utilization / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data* / Q000639:trends; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification; D009517:New South Wales / Q000453:epidemiology; D011446:Prospective Studies; D018805:Sepsis / Q000188:drug therapy / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotic resistance; Antibiotic stewardship; MRSA; Nosocomial infection