Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Majorcan hospitals: high prevalence of the epidemic clone EMRSA-15

Abstract

Clinical isolates (n = 389) of methicillin-resistant Staphylococcus aureus (MRSA) recovered from 371 patients between January 2003 and June 2004 at the three major public hospitals on the island of Majorca, Spain were studied. The clonal relatedness of MRSA isolates was determined by pulsed-field gel electrophoresis (PFGE) after digestion with SmaI. During the study period, MRSA was found in 31% of patients with S. aureus-positive cultures. PFGE analysis identified three predominant clones, affecting 94% of the patients. The three clones had been detected since 1999 in one hospital, and were designated as clones A, B and C. Whereas clones A and B (multidrug-resistant) were related to the two most prevalent clones in Spain at this time, clone C was identical to EMRSA-15, currently one of the most common MRSA clones in UK hospitals and also detected in other countries, but rarely in Spanish hospitals. This imported epidemic clone was detected in c. 10% of patients admitted to one of the three hospitals in 2002, but its prevalence has increased significantly (32% of the patients investigated in the three hospitals in the present study), and this clone also accounted for 44% of the isolates from non-hospitalised patients. Even though EMRSA-15 showed the least multidrug resistance of the three major clones, it was apparently more virulent, since it was associated significantly (p 0.001) with bacteraemia, and positive blood cultures were documented for 21% of the patients infected by this clone, compared with only 10% and 7% of patients infected with clones A and B, respectively.

Changes in the Clonal Nature and Antibiotic Resistance Profiles of Methicillin-Resistant Staphylococcus aureus Isolates Associated with Spread of the EMRSA-15 Clone in a Tertiary Care Portuguese Hospital

“…However, we found an interesting and statistically significant association (P ϭ 0.005) of this clone with patients who usually attend the DFOU versus those patients who do not attend the DFOU. Our findings support the data recently published by Alcoceba et al reporting the spread of the EMRSA-15 clone more frequently among nonhospitalized patients (emergency room and outpatient departments) than among hospitalized patients from the three main public Majorcan hospitals (6). Nevertheless and despite the suggestion by Alcoceba et al about the movement of EMRSA-15 occurring mainly from the community to the hospital setting, the MRSA isolates recovered from the outpatients attending the DFOU were classified as hospital acquired since all of the patients had had previous visits to the DFOU, an average of four in the previous 12 months, and 70% had been previously admitted as inpatients to HGSA.…”

“…In contrast with MRSA strains isolated in HGSA during the last decade (1990 to 2000), which were typically multiresistant, a significant change was observed, at least since 2001, with the increasing (6). Resistance to SXT was confirmed to be an important phenotypic marker for the identification of the Brazilian clone (ST239, SCCmec type IIIA, PFGE type B) among the multiresistant MRSA isolates, since 92% (33 out of 36) of the MRSA isolates found to be resistant to SXT presented PFGE type B.…”

“…The EMRSA-15 clone is one of the pandemic MRSA clones (18) and has been identified in several countries such as The Netherlands (18,62), Denmark (21), Germany (63), Ireland and Sweden (18), the Czech Republic (32, 33), Australia and New Zealand (23,46), Kuwait (59), and Spain (6,35,47).…”

Characterization of Baseline Methicillin-Resistant Staphylococcus aureus Isolates Recovered from Phase IV Clinical Trial for Linezolid

“…This pandemic clone has been identified in several European countries, but it still comprised less than 2% of the nosocomial MRSA isolates recovered in Spanish hospitals (24). More recently, a higher prevalence of EMRSA-15 (32%) was noted in Majorcan islands hospitals (2). In the present study, all isolates recovered from Spain (Seville and Cordoba) belonged to EMRSA-15, indicating that this clone may have become more prevalent in that country; however, only three isolates were evaluated.…”

Changing Patterns in Frequency of Recovery of Five Methicillin-Resistant Staphylococcus aureus Clones in Portuguese Hospitals: Surveillance over a 16-Year Period

“…Besides having been detected in several countries (http://saureus.mlst.net), EMRSA-15 is replacing previous established clones in different regions of the world. In Europe, it was found in a number of hospitals throughout Germany (53), and it is currently established as the major clone in the Czech Republic (33) and in the Majorcan islands (7). A recent study performed in a hospital in Oporto, Portugal, showed that clone EMRSA-15, which might have been introduced in the hospital in 2001, represents the overwhelming majority (79%) of the isolates collected between 2003 and 2005 (8).…”