title: Increasing incidence of Clostridium difficile infection, Australia, 2011-2012.
abstract: OBJECTIVE
  To report the quarterly incidence of hospital-identified Clostridium difficile infection (HI-CDI) in Australia, and to estimate the burden ascribed to hospital-associated (HA) and community-associated (CA) infections.
  
  
  METHODS
  Prospective surveillance of all cases of CDI diagnosed in hospital patients from 1 January 2011 to 31 December 2012 in 450 public hospitals in all Australian states and the Australian Capital Territory. All patients admitted to inpatient wards or units in acute public hospitals, including psychiatry, rehabilitation and aged care, were included, as well as those attending emergency departments and outpatient clinics.
  
  
  METHODS
  Incidence of HI-CDI (primary outcome); proportion and incidence of HA-CDI and CA-CDI (secondary outcomes).
  
  
  RESULTS
  The annual incidence of HI-CDI increased from 3.25/10 000 patient-days (PD) in 2011 to 4.03/10 000 PD in 2012. Poisson regression modelling demonstrated a 29% increase (95% CI, 25% to 34%) per quarter between April and December 2011, with a peak of 4.49/10 000 PD in the October-December quarter. The incidence plateaued in January-March 2012 and then declined by 8% (95% CI, - 11% to - 5%) per quarter to 3.76/10 000 PD in July-September 2012, after which the rate rose again by 11% (95% CI, 4% to 19%) per quarter to 4.09/10 000 PD in October-December 2012. Trends were similar for HA-CDI and CA-CDI. A subgroup analysis determined that 26% of cases were CA-CDI.
  
  
  CONCLUSIONS
  A significant increase in both HA-CDI and CA-CDI identified through hospital surveillance occurred in Australia during 2011-2012. Studies are required to further characterise the epidemiology of CDI in Australia.
authors.affiliation: Pathology and Laboratory Medicine, University of Western Australia, Perth, WA, Australia. claudia.slimings@uwa.edu.au.
authors.forename: Claudia
authors.initials: C
authors.lastname: Slimings
authors.affiliation: Western Australia Department of Health, Perth, WA, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Armstrong
authors.affiliation: Infectious Diseases and Infection Prevention and Control Unit, ACT Health, Canberra, ACT, Australia.
authors.forename: Wendy D
authors.initials: WD
authors.lastname: Beckingham
authors.affiliation: Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre, Melbourne, VIC, Australia.
authors.forename: Ann L
authors.initials: AL
authors.lastname: Bull
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Hall
authors.affiliation: Canberra Hospital and Health Services, Canberra, ACT, Australia.
authors.forename: Karina J
authors.initials: KJ
authors.lastname: Kennedy
authors.affiliation: Centre for Healthcare Related Infection Surveillance and Prevention, Queensland Health, Brisbane, QLD, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Marquess
authors.affiliation: Western Australia Department of Health, Perth, WA, Australia.
authors.forename: Rebecca
authors.initials: R
authors.lastname: McCann
authors.affiliation: Canberra Hospital and Health Services, Canberra, ACT, Australia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Menzies
authors.affiliation: Faculty of Nursing and Health, Avondale College for Higher Education, Sydney, NSW, Australia.
authors.forename: Brett G
authors.initials: BG
authors.lastname: Mitchell
authors.affiliation: Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre, Melbourne, VIC, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Richards
authors.affiliation: Clinical Excellence Commission, Sydney, NSW, Australia.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Smollen
authors.affiliation: Western Australia Department of Health, Perth, WA, Australia.
authors.forename: Lauren
authors.initials: L
authors.lastname: Tracey
authors.affiliation: Communicable Disease Control Branch, Department of Health and Ageing, Adelaide, SA, Australia.
authors.forename: Irene J
authors.initials: IJ
authors.lastname: Wilkinson
authors.affiliation: Tasmanian Infection Prevention and Control Unit, Department of Health and Human Services, Hobart, TAS, Australia.
authors.forename: Fiona L
authors.initials: FL
authors.lastname: Wilson
authors.affiliation: Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre, Melbourne, VIC, Australia.
authors.forename: Leon J
authors.initials: LJ
authors.lastname: Worth
authors.affiliation: Pathology and Laboratory Medicine, University of Western Australia, Perth, WA, Australia.
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Riley
mesh_terms: D001315:Australia / Q000453:epidemiology; D016360:Clostridioides difficile; D017714:Community-Acquired Infections / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D016012:Poisson Distribution; D011159:Population Surveillance