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This article is part of the supplement: International Conference on Prevention & Infection Control (ICPIC 2011)

Open Access Poster presentation

Prevalence of livestock associated MRSA in blood isolates

BV Cleef12*, BV Benthem1, J Monen1, A Haenen1, NVD Sande-Bruinsma1 and J Kluytmans2

  • * Corresponding author: BV Cleef

Author Affiliations

1 Centre for Infectious Disease Control Netherlands, RIVM National Institute for Public Health and the Environment, Bilthoven, Netherlands

2 Department of Medical Microbiology and Infection Prevention, VU University Medical Centre, Amsterdam, Netherlands

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BMC Proceedings 2011, 5(Suppl 6):P170  doi:10.1186/1753-6561-5-S6-P170


The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1753-6561/5/S6/P170


Published:29 June 2011

© 2011 Cleef et al; licensee BioMed Central Ltd.

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction / objectives

In the Netherlands there is an extensive reservoir of livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs and calves. The aim of this study was to establish the prevalence of LA-MRSA in human blood isolates.

Methods

This study was based on data from the national antibiotic resistance surveillance (ISIS-AR) in The Netherlands. The 22 participating laboratories cover approximately 50% of all hospital beds. Data from 2008 through 2010 on S. aureus (SA) isolates were evaluated for methicillin resistance and spa-type, to identify LA-MRSA strains. Only the first isolate per patient was included. For this preliminary examination, we used tetracycline resistance as an indicator for LA-MRSA. In further analysis presented at the congress, spa-types will be included.

Results

The proportion of MRSA of all episodes of SA bacteremia was 1.5% (51/3355). Of the MRSA isolates with an antibiotic resistance profile, 17% were tetracycline resistant (8/48, 95%CI 9-30%). The proportion of tetracycline resistance in MRSA isolates from other sources was 41% (872/2124, 95%CI 39-43%, chi-square blood vs non-blood p<0.0001). Extrapolation results in an average annual incidence of 5.3 patients with LA-MRSA bacteremia in The Netherlands.

Conclusion

The current annual incidence of LA-MRSA bacteremia is low. Tetracycline resistant MRSA is significantly less prevalent in MRSA blood isolates compared to non-blood isolates. This can be the result of an excessive screening regime resulting in overrepresentation in non-invasive isolates or a decreased virulence of the livestock associated strains.

Disclosure of interest

None declared.