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Molecular characterisation of Staphylococcus aureus from Dutch general practice patients

Abstract number: R2345

Donker G.A., Nys S., Driessen C., Deurenberg R.H., Stobberingh E.E.

Objectives: Meticillin-resistant Staphylococcus aureus (MRSA) is an increasing problem, both in the community (community-associated (CA)-MRSA) and in the hospital environment (hospital-associated (HA)-MRSA). In order to investigate the prevalence, the antibiotic susceptibility patterns and the population structure of S. aureus in the community, nasals swabs from patients without infectious symptoms visiting their general practitioner (GP) were taken and analysed.

Methods: GPs from 30 practices, situated all over The Netherlands, send nasal swabs from their patients to the laboratory for isolating and identification of S. aureus. The antibiotic susceptibility pattern to several classes of antimicrobial agents was determined according to CLSI guidelines, and the genetic background of the isolates was determined using spa typing and the algorithm based upon repeat pattern (BURP).

Results: From 617 out of 2,691 (23%) swabs, S. aureus was isolated. Of the 617 isolates, 595 were available for further analyses. The prevalence of resistance to penicillin, ciprofloxacin, macrolides, tetracyclin and fusidic acid was 68%, 1%, 5%, 3% and 6%, respectively. All isolates were sensitive to cefuroxime, clindamycin, imipenem, linozelid, meropenem. moxifloxacin, teicoplanin, trimethroprim/sulfamethoxazole and vancomycin. No MRSA isolates were found.

Typing revealed 244 spa types (of which 48 were new types), and 173 were clustered into 23 spa-clonal complexes (spa-CCs) (490 isolates). The remaining isolates could not be classified into spa-CCs. Up to 55% of the isolates were associated with a genetic background common to the endemic CA- or HA-MRSA clones, e.g. clonal complex (CC)1, CC5. CC8, CC22, CC30, and CC45. The remaining isolates were mainly associated with CC7, CC12, CC15, CC26, CC101 and CC121, commonly observed among MSSA worldwide.

Conclusions:

1The S. aureus prevalence among general practice patients was 23%.

2No MRSA isolated were observed in the population.

3The low resistance percentages suggest that the increased resistance of S. aureus in hospitals is very likely not due to a reservoir outside the hospital.

4Over half of the MSSA isolates had a genetic background common to endemic MRSA clones.

5Several other MSSA lineages, not related to MRSA, were prevalent among the general practice patients.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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