Epidemiology and Infection

  • Epidemiology and Infection / Volume 142 / Issue 06 / June 2014, pp 1310-1316
  • Copyright © Cambridge University Press 2013 The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution licence <http://creativecommons.org/licenses/by/3.0/>.
  • DOI: http://dx.doi.org/10.1017/S0950268813002033 (About DOI), Published online: 20 August 2013

Original Papers

Bacterial infections

Prevalence and molecular epidemiology of Staphylococcus aureus in Swedish nursing homes – as revealed in the SHADES study  


a1 Clinical Microbiology, Department of Laboratory Medicine, Ryhov County Hospital, Jönköping

a2 Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, Linköping

a3 Ödeshög Health Care Centre, Ödeshög

a4 Division of Community Medicine, Department of Medical and Health Sciences, Linköping University, Linköping

a5 Division of General Practice/Family Medicine, Department of Clinical Sciences in Malmö, Lund University, Malmö


Knowledge of carriage and population dynamics of Staphylococcus aureus is crucial for infection risk assessment and to reveal transmission patterns of strains. We report the prevalence and molecular epidemiology of S. aureus in elderly people (n = 290) living in nursing homes in three cities in the south of Sweden. The overall carriage prevalence rate was 48% when results from nares (31%) and throat (34%) samples were combined. Common spa types were equally distributed but a frequent type, t160, was found only in one of the regions. Carriage of different spa types was detected in 23% of individuals and antimicrobial resistance rates were higher in S. aureus isolates from those carrying more than one spa type. Five of the 21 individuals who carried different spa types were colonized simultaneously with resistant and non-resistant strains. Seventeen per cent of the individuals carried S. aureus of the same spa type on all occasions. Methicillin resistance was not detected. In conclusion we found a high prevalence of S. aureus in this elderly population with a high rate of dual colonization with different spa types. We also found signs of institutional spread of one strain.

(Received May 03 2013)

(Revised July 29 2013)

(Accepted July 29 2013)

(Online publication August 20 2013)

Key words

  • Colonization;
  • molecular typing;
  • multiclonality;
  • nursing home;
  • spa type


c1 Author for correspondence: Miss L. Stark, Department of Clinical Microbiology, Ryhov County Hospital, SE-551 85 Jönköping, Sweden. (Email: lisa.stark@lj.se)


  This study is part of the SHADES programme (the Study of Health and Drugs among the Elderly in Swedish Nursing Homes), which in general focuses on mortality, morbidity, health conditions and drug use in elderly individuals living in community dwellings in Sweden.