title: Population-based incidence and comparative demographics of community-associated and healthcare-associated Escherichia coli bloodstream infection in Auckland, New Zealand, 2005-2011.
abstract: BACKGROUND
  Escherichia coli is a major human pathogen, both in community and healthcare settings. To date however, relatively few studies have defined the population burden of E. coli bloodstream infections. Such information is important in informing strategies around treatment and prevention of these serious infections. Against this background, we performed a retrospective, population-based observational study of all cases of E. coli bacteremia in patients presenting to our hospital between January 2005 and December 2011.
  
  
  METHODS
  Auckland District Health Board is a tertiary-level, university-affiliated institution serving a population of approximately 500,000, within a larger metropolitan population of 1.4 million. We identified all patients with an episode of bloodstream infection due to E. coli over the study period. A unique episode was defined as the first positive E. coli blood culture taken from the same patient within a thirty-day period. Standard definitions were used to classify episodes into community- or healthcare-associated E. coli bacteremia. Demographic information was obtained for all patients, including: age; gender; ethnicity; length of stay (days); requirement for intensive care admission and all-cause, in-patient mortality.
  
  
  RESULTS
  A total of 1507 patients had a unique episode of E. coli bacteremia over the study period. The overall average annual incidence of E. coli bacteremia was 52 per 100,000 population, and was highest in the under one year and over 65-year age groups. When stratified by ethnicity, rates were highest in Pacific Peoples and Māori (83 and 62 per 100,000 population respectively). The incidence of community-onset E. coli bacteremia increased significantly over the study period. The overall in-hospital mortality rate was 9% (135/1507), and was significantly higher in patients who had a hospital-onset E. coli bacteremia.
  
  
  CONCLUSIONS
  Our work provides valuable baseline data on the incidence of E. coli bacteremia in our locale. The incidence was higher that that described from other developed countries, with significant demographic variation, most notably in ethnic-specific incidence rates. Future work should assess the possible reasons for this disparity.
authors: Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand. dwilliamson@adhb.govt.nz.
authors: Deborah A
authors: DA
authors: Williamson
authors: Alwin
authors: A
authors: Lim
authors: Siouxsie
authors: S
authors: Wiles
authors: Sally A
authors: SA
authors: Roberts
authors: Joshua T
authors: JT
authors: Freeman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D003710:Demography; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D012189:Retrospective Studies; D055815:Young Adult
references: J Antimicrob Chemother. 2011 Dec;66(12):2888-90
references: 21933789
references: J Antimicrob Chemother. 2007 Dec;60(6):1355-60
references: 17923453
references: J Infect Dis. 2005 May 1;191(9):1523-9
references: 15809912
references: Clin Microbiol Infect. 2012 Mar;18(3):268-81
references: 21793988
references: Lancet. 2012 Mar 24;379(9821):1112-9
references: 22353263
references: Arch Intern Med. 2007 Apr 23;167(8):834-9
references: 17452548
references: J Clin Microbiol. 2012 Feb;50(2):312-7
references: 22162561
references: J Antimicrob Chemother. 2012 Jun;67(6):1514-24
references: 22438437
references: Scand J Infect Dis. 1995;27(3):253-7
references: 8539550
references: Pediatr Infect Dis J. 2013 Aug;32(8):923-5
references: 23518822
references: N Z Med J. 2000 Aug 25;113(1116):358-61
references: 11130369
references: PLoS One. 2013 Apr 25;8(4):e62020
references: 23637953
references: Epidemiol Infect. 2013 Jan;141(1):174-80
references: 22417845
references: Intern Med J. 2001 Mar;31(2):97-103
references: 11480485
references: Euro Surveill. 2011 Mar 17;16(11):
references: 21435327
references: Antimicrob Agents Chemother. 2007 Jun;51(6):1987-94
references: 17387156
references: Int J Antimicrob Agents. 2012 Jun;39(6):529-33
references: 22526013
references: N Z Med J. 1996 Sep 27;109(1030):356-8
references: 8890860
references: Postgrad Med J. 2011 Nov;87(1033):757-62
references: 21798969
references: N Z Med J. 2011 Apr 15;124(1332):21-30
references: 21747420
references: Vaccine. 2011 Sep 16;29(40):7100-6
references: 21803101
references: Epidemiol Infect. 2007 Jan;135(1):163-70
references: 16753076
references: Microbes Infect. 2003 Apr;5(5):449-56
references: 12738001
references: BMC Infect Dis. 2012 Apr 09;12:85
references: 22487002
references: Clin Microbiol Infect. 2012 Jun;18(6):E170-6
references: 22512663
references: Clin Microbiol Infect. 2008 Nov;14(11):1041-7
references: 19040476
references: N Z Med J. 2010 Mar 05;123(1310):62-73
references: 20360780
references: Epidemiol Infect. 2009 May;137(5):717-26
references: 18925988
references: Antimicrob Agents Chemother. 2010 Oct;54(10):4085-91
references: 20660675
references: BMC Infect Dis. 2012 Oct 09;12:249
references: 23043704
references: Med J Aust. 2008 Feb 18;188(4):209-13
references: 18279126
references: Clin Infect Dis. 2012 May;54(10):1406-12
references: 22419681
references: Lancet Infect Dis. 2012 Feb;12(2):103-4
references: 22281141