Emergence of a methicillin-resistant Staphylococcus aureus USA300 clone lacking arginine catabolic mobile element, in Spain

Abstract number: P1585

Molinos S., Ehricht R., Giménez M., Monecke S., Rodrigo C., Prat C., Sopena N., Ausina V.

Objectives: Community-associated MRSA (CA-MRSA) disease usually presents as pyogenic skin and soft tissue infections (SSTIs) in previously healthy individuals. USA300, ST-8 is the most prevalent clone in this country and contains a genomic island, known as arginine catabolic mobile element (ACME), which encodes an arginine deaminase. This enzyme may enhance the virulence of USA 300 by enabling it to colonise and evade host defences.

In Spain, CA-MRSA isolates don't belong to the main European clone ST80, but to the ST8.

Here, we report the first three Spanish isolates of the CA-MRSA USA 300 ST-8 clone without the ACME-associated arcA gene in their genetic background.

Methods: DNA microarrays based on the Array-Tube platform (CLONDIAG, Jena, Germany) were used for genotyping three isolates from two children with superficial skin infections and one adult with septic arthritis and bacteraemia (Table 1).

Results: Hybridisation patterns for the agr-specific probes showed that three isolates matched to agr type I, carried a type IV staphylococcal cassette (SCC) and belonged to CA-MRSA of clonal group ST8.All isolates contained the genes for both toxin Panton-Valentine leukocidin (PVL) components (lukF-PV and lukS-PV). Moreover, the three isolates also lack ACME-arcA gene. In addition, all isolates contained the chp gene for chemotaxis inhibitory protein (CHIPS).

Conclusion: The three isolates of our patients lacked the ACME. To date, these are the first Spanish isolates of ACME-negative USA300.

Our study shows the emergence and spread of a clone that could potentially change the clinical spectrum of S. aureus infections in our community; thus, the comparison of the virulence gene content of well characterised isolates causing different clinical syndromes is crucial in predicting the clinical outcome and the most accurate treatment for CA-MRSA infections.

CaseAgePatient locationInfectionTreatmentRisk factorsEvolution
I6 monthsPaediatricsImpetigo on the lipClarithromycin 125/5 ml, susp. q12 h 10 daysCure
II4 yearsPaediatricsBreast abscess.
Symptoms started twelve days before
Amoxicillin/clavulanic 2.8 ml susp. q8 h 5 days
<5 cm/drainage
III47 yearsEmergencySeptic arthritis (ankle) and bacteraemiaVancomycin 1 g q12 and clindamycin 600 mg q8 23 days
+ ciprofloxacin 750 mg q12 8 weeks
Diabetes, obesity and dilated cardiomyopathyCure

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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