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

Abstract

A total of 629 nonduplicate methicillin-resistant Staphylococcus aureus MRSA isolates were recovered between June and November 2006 from 11 hospitals located in different areas of Portugal. Selected isolates (n ‫؍‬ 271, 43%) were typed by pulsed-field gel electrophoresis (PFGE), representatives of which were additionally characterized by spa typing, multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, and the presence of Panton-Valentine leukocidin (PVL). The 271 isolates were classified into 13 different clonal types. Three pandemic clones included the majority (n ‫؍‬ 241, 88%) of the isolates and were observed in several hospitals: (i) EMRSA-15 (54%)-PFGE type A, ST22, spa type t022, SCCmec IV-was found in the 11 hospitals studied and was identified as the major clone in seven of them; (ii) the New York/Japan clone (17%)-PFGE B, ST5, spa type t067, SCCmec II-was identified in nine hospitals and represented the major clone in four; and (iii) the Brazilian MRSA (17%)-PFGE C, ST239, spa type t037, SCCmec IIIA-was also detected in nine hospitals but never as the main clone. All isolates tested were PVL negative. Clone EMRSA-15 is currently the predominant MRSA clonal type circulating in Portuguese hospitals, but a new wave of MRSA has emerged in the country with the recent introduction and spread of the New York/Japan clone. The Brazilian MRSA that was the leading clone in Portugal in the late 1990s is declining and being progressively replaced by the two former clones. We report the first isolate SCCmec type V (ST45) in Portugal.

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

“…This report was later confirmed by Aires de Sousa et al (1), who described that the majority of isolates (54%) recovered from 11 Portuguese hospitals belonged to EMRSA-15. Interestingly, in the same report, the New York/Japan clone (ST5-SCCmec II), first detected in a Portuguese hospital in 2005 (a single isolate), and the Hungarian/Brazilian clone shared the same overall prevalence (17%), but the New York/Japan clone prevailed among hospitals in Lisbon, Portugal (1). In the present study, a similar coexistence of these three clones was observed among Portuguese MRSA isolates; however, the New York/Japan clone was the dominant clone, consisting of 29.2% of all isolates (18.8% of EMRSA-15 isolates).…”

“…During the last few decades, methicillin-resistant Staphylococcus aureus (MRSA) has been a worldwide clinical problem and has increasingly been responsible for infections in both the community and hospital settings (1). This remarkable pathogen has acquired resistance to several classes of antimicrobial agents, therefore commonly exhibiting the multidrug resistance (MDR) phenotype, which poses a continuous threat for antimicrobial therapy (11,14).…”

High prevalence of ST121 in community-associated methicillin-susceptible Staphylococcus aureus lineages responsible for skin and soft tissue infections in Portuguese children

“…Nevertheless, since it was recovered from a periumbilical exudate of a neonate, the connection to the nosocomial setting could not be discarded, as ST80 PVLpositive isolates were already described as nosocomial isolates in the late 1990s [33]. Regular surveillance studies in Portuguese hospitals [34], together with the present study, seem to indicate that CA-MRSA-ST80 is not widely spread in Portugal in contrast to what was described in several other European countries [21,35].…”

Genomic insights into the emergence and spread of international clones of healthcare-, community- and livestock-associated meticillin-resistant Staphylococcus aureus : Blurring of the traditional definitions

“…The human EMRSA-15 epidemic has also spread into the companion animal population [22,23], with veterinary hospitals also being healthcare settings that may experience high levels of transmission [24]. A c c e p t e d M a n u s c r i p t 12 documented in Portugal, Singapore and Australia [25][26][27]. One feature that may contribute to its success is the SCCmec IV element that this clone carries, which has a lower fitness cost than the larger SCCmec elements such as SCCmec types II and III that were prevalent in earlier HA-MRSA clones [28].…”