Objectives: We determined the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage upon hospital admission, among patients who were screened preoperatively for nasal S. aureus carriage between 2010 and 2017. We also aimed to evaluate the prevalence of MRSA carriers without the standard risk factors.
Methods: We conducted an observational study to determine the prevalence of MRSA nasal carriage among patients who were screened preoperatively for nasal S. aureus carriage between 2010 and 2017. Samples of cardiothoracic patients were tested by polymerase chain reaction (PCR), other samples were cultured using chromogenic agar plates. A Poisson regression model with robust error variance was used to assess whether there was a trend in the prevalence of MRSA over time.
Results: In total, 31 093 nasal swabs were obtained from 25 660 patients. Three-hundred and seventy-five swabs (1.2%) had an invalid result. Therefore, 30 718 swabs (98.8%) were included in our analysis. Overall, S. aureus was detected in 7981/30 718 patients (26.0% 95% CI 25.5-26.5%) of whom 41 were MRSA (0.13% 95% CI 0.10-0.18%). The MRSA prevalence varied from 0.03% to 0.17% over the years without evidence of a changing trend over time (p = 0.40). Results of the questionnaire revealed that 30 of the 41 patients (73.2%) had no known risk factors for MRSA carriage (0.10%; 95% CI 0.07-0.14%).
Conclusion: Our study revealed a sustained low prevalence of MRSA carriage upon hospital admission over 7 years. This supports the effectiveness of the Dutch Search and Destroy policy, in combination with a restrictive antibiotic prescription policy.
Keywords: Antimicrobial resistance; Infection control; Livestock-associated MRSA; MLVA; MRSA; Search and destroy; Staphylococcus aureus.
Copyright © 2019 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.