gms | German Medical Science

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010)

Deutsche Gesellschaft für Infektiologie,
Deutsche AIDS-Gesellschaft,
Deutsche Gesellschaft für Tropenmedizin und Internationale Gesundheit,
Paul-Ehrlich-Gesellschaft für Chemotherapie

23.06. - 26.06.2010, Köln

Staphylococcus aureus infection following nasal colonization: markedly increased risk with MRSA in younger patients

Infektionen mit Staphylokokkus aureus nach nasaler Kolonisation – deutlich erhöhtes Risiko durch MRSA bei jüngeren Patienten

Meeting Abstract

  • U. Seybold - Ludwig-Maximilians-Universität München, Infektionsabteilung, Medizinische Poliklinik – Innenstadt, München, Germany
  • S. Schubert - Ludwig-Maximilians-Universität, Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Abteilung für Bakteriologie, München, Germany
  • J. R. Bogner - Ludwig-Maximilians-Universität München, Infektionsabteilung, Medizinische Poliklinik – Innenstadt, München, Germany
  • M. Hogardt - Ludwig-Maximilians-Universität, Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Abteilung für Bakteriologie, München, Germany; Institut für Mikrobiologie der Bundeswehr, München, Germany

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010). Köln, 23.-26.06.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. DocINF 14-3

DOI: 10.3205/10kit030, URN: urn:nbn:de:0183-10kit0303

Published: June 2, 2010

© 2010 Seybold et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objectives: S. aureus colonization, present in about 1/3 of the population, is a predictor of subsequent infection. Objective of this study was to define effect modifiers of this association.

Methods: Adult patients with growth of S. aureus from anterior nares swabs were identified at the University of Munich hospitals from the microbiology data repository. Risk factors for subsequent S. aureus infection were identified in a case-control study. Patients with culture of S. aureus from a clinical specimen within 90 days of the nares culture were defined as cases.

Results: Between Jan 1 2005 and April 1 2009 2155 patients with nasal S. aureus colonization were identified. Follow-up of ≥90 days was documented for 645 patients (30%), defining the study population.

Median age was 58 years, 421 (65%) patients were male. In 159 (25%) patients the S. aureus isolate was oxacillin resistant (MRSA). During the subsequent 90 days ≥1 clinical culture was positive for S. aureus in 131 (20%) patients. In the 514 control patients there either was no further S. aureus culture (462 patients, 72%) or it was detected only in surveillance cultures (52 patients, 8%).

In bivariate analysis S. aureus infection was more likely in patients >40 years (OR 2.3, p=0.0009), from campus B (OR 1.8, p=0.005), admitted to the hospital (OR 2.5, p=0.003), those with a preceding S. aureus culture (OR 4.2, p<0.001), and MRSA carriers (OR 4.8, p<0.001).

Multivariate analysis confirmed a S. aureus culture in the 90 days preceding the nares culture (aOR 2.35, 95% CI 1.46–3.80, p=0.0005) as independent predictor of subsequent S. aureus infection. In addition, interaction of patient age with oxacillin resistance of the nares isolate was detected. Thus, age >40 years was a risk factor, but only for MSSA carriers (aOR 3.02, 95% CI 1.17–7.78, p=0.02), not MRSA carriers. Oxacillin resistance of the nares isolate also was an independent predictor, already significant for patients >40 years (aOR 2.50, 95% CI 1.41–4.14, p=0.0004), but even more so for patients ≤40 years (aOR 12.38, 95% CI 3.01–50.87, p=0.0005).

Conclusion: At our institution 20% of S. aureus carriers developed an infection within 90 days. Preceding S. aureus detection, older age for MRSA carriers, and oxacillin resistance of the nares isolate, most markedly in younger patients, characterized patients with increased risk of subsequent infection. These patients may specifically benefit from decolonization regimens to prevent infection.