Scientific article

Evaluating the probability of previously unknown carriage of MRSA at hospital admission

Published inThe American journal of medicine, vol. 119, no. 3, p. 275e215-223
Publication date2006

PURPOSE: We determined the prevalence and risk profile of patients with previously unknown carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission. SUBJECTS AND METHODS: We conducted a 7-month, prospective case-controlled study in adult inpatients admitted to a university hospital with endemic MRSA. Multivariate conditional logistic regression for data sets matched 1:4 was performed to identify the risk profile of newly identified MRSA carriers. RESULTS: Overall, 399 of 12072 screened admissions (prevalence, 3.3%) were found colonized (n = 368, 92%) or infected (n = 31, 8%) with MRSA. In 204 cases (prevalence, 1.7%), MRSA carriage was newly identified. Without screening on admission, 49% (196/399) of MRSA carriers would have been missed. We identified nine independent risk factors for newly identified MRSA carriage at admission (adjusted odds ratio): male sex (1.9); age greater than 75 years (2.0); receipt of fluoroquinolones (2.7), cephalosporins (2.1), and carbapenems (3.2) in the last 6 months; previous hospitalization (1.9) or intravenous therapy (1.7) during the last 12 months; urinary catheter at admission (2.0); and intrahospital transfer (2.4). A risk score (range, 0-13) was calculated by adding points assigned to these variables. On the basis of analysis of 1006 patients included in the case-controlled study, the probability of MRSA carriage was 8% (28/342) in patients with a low score (< or =1), 19% (92/482) in patients with an intermediate score (2-4), and 46% (84/182) in patients with a high score (> or =5). The risk score had good discrimination (c-statistic, 0.73) and showed excellent calibration (P =.88). CONCLUSIONS: On-admission prevalence of previously unknown MRSA carriers was high. Applying the risk score to newly admitted patients with an intermediate or high probability of MRSA carriage could allow a more effective MRSA control strategy.

  • Aged
  • Carrier State/ diagnosis/epidemiology
  • Case-Control Studies
  • Cross Infection/epidemiology/ prevention & control
  • Female
  • Hospitalization
  • Humans
  • Male
  • Methicillin Resistance
  • Predictive Value of Tests
  • Prevalence
  • Probability
  • Risk Factors
  • Staphylococcal Infections/ epidemiology/transmission
  • Switzerland/epidemiology
Citation (ISO format)
HARBARTH, Stéphan Juergen et al. Evaluating the probability of previously unknown carriage of MRSA at hospital admission. In: The American journal of medicine, 2006, vol. 119, n° 3, p. 275e215–223. doi: 10.1016/j.amjmed.2005.04.042
Updates (1)
ISSN of the journal0002-9343

Technical informations

Creation06/21/2010 10:24:38 AM
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Update time03/14/2023 3:44:02 PM
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