title: Incidence, trends and demographics of Staphylococcus aureus infections in Auckland, New Zealand, 2001-2011.
abstract: BACKGROUND
  New Zealand has a higher incidence of Staphylococcus aureus disease than other developed countries, with significant sociodemographic variation in incidence rates. In contrast to North America, the majority of disease is due to methicillin-susceptible S. aureus (MSSA), although relatively little is known about the comparative demographics of MSSA and methicillin-resistant S. aureus (MRSA) infections in New Zealand.
  
  
  METHODS
  Our objectives were to describe the trends, incidence and patient demographics of all S. aureus infections in patients presenting to our institution between 2001 and 2011, and compare the epidemiology of MSSA and MRSA infections. We identified all patients with S. aureus infections over the study period. A unique S. aureus infection was defined as the first positive S. aureus culture taken from the same patient within a thirty-day period. Standard definitions were used to classify episodes into community- or healthcare-associated S. aureus infection.
  
  
  RESULTS
  There were 16,249 S. aureus infections over the study period. The incidence increased significantly over the study period from 360 to 412 per 100,000 population (P < 0.001), largely driven by an increase in community-associated non-invasive MSSA infections. When compared with MSSA infections, patients with non-multiresistant MRSA infections were more likely to be older, have hospital-onset infections and be Māori or Pacific Peoples.
  
  
  CONCLUSIONS
  Our work provides valuable baseline data on the epidemiology and trends of S. aureus infections in New Zealand. The significant increase in community-associated S. aureus infections is of public health importance. Future studies should investigate the reasons underlying this concerning trend.
authors.affiliation: Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand. deb.williamson@auckland.ac.nz.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Williamson
authors.forename: Alwin
authors.initials: A
authors.lastname: Lim
authors.forename: Mark G
authors.initials: MG
authors.lastname: Thomas
authors.forename: Michael G
authors.initials: MG
authors.lastname: Baker
authors.forename: Sally A
authors.initials: SA
authors.lastname: Roberts
authors.forename: John D
authors.initials: JD
authors.lastname: Fraser
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Ritchie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D003710:Demography; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D016106:Methicillin Resistance / Q000187:drug effects; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents