Extensive Dissemination of Methicillin-Resistant Staphylococcus aureus (MRSA) between the Hospital and the Community in a Country with a High Prevalence of Nosocomial MRSA

Abstract

According to the EARS-Net surveillance data, Portugal has the highest prevalence of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) in Europe, but the information on MRSA in the community is very scarce and the links between the hospital and community are not known. In this study we aimed to understand the events associated to the recent sharp increase in MRSA frequency in Portugal and to evaluate how this has shaped MRSA epidemiology in the community. With this purpose, 180 nosocomial MRSA isolates recovered from infection in two time periods and 14 MRSA isolates recovered from 89 samples of skin and soft tissue infections (SSTI) were analyzed by pulsed-field gel electrophoresis (PFGE), staphylococcal chromosome cassette mec (SCCmec) typing, spa typing and multilocus sequence typing (MLST). All isolates were also screened for the presence of Panton Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME) by PCR. The results showed that ST22-IVh, accounting for 72% of the nosocomial isolates, was the major clone circulating in the hospital in 2010, having replaced two previous dominant clones in 1993, the Iberian (ST247-I) and Portuguese (ST239-III variant) clones. Moreover in 2010, three clones belonging to CC5 (ST105-II, ST125-IVc and ST5-IVc) accounted for 20% of the isolates and may represent the beginning of new waves of MRSA in this hospital. Interestingly, more than half of the MRSA isolates (8/14) causing SSTI in people attending healthcare centers in Portugal belonged to the most predominant clones found in the hospital, namely ST22-IVh (n = 4), ST5-IVc (n = 2) and ST105-II (n = 1). Other clones found included ST5-V (n = 6) and ST8-VI (n = 1). None of the MRSA isolates carried PVL and only five isolates (ST5-V-t179) carried ACME type II. The emergence and spread of EMRSA-15 may be associated to the observed increase in MRSA frequency in the hospital and the consequent spillover of MRSA into the community.

Antibiograms, toxin profiling and molecular typing of Staphylococcus aureus isolates from two tertiary hospitals in Jordan

“…For instance, in 2010 MRSA accounted for 25-50% of S. aureus specimens in southern Europe and UK [25]. Similarly, in Portugal, the MRSA prevalence reached 52.2% in 2010 [26]. In contrast to these results, in Skane county of southern Sweden, the reported cases of MRSA were less than in the southern Europe Counties, however, the incidence of MRSA infection was rising as the number of cases increased from 31 in year 2000 to 315 cases in year 2010 [25].…”

Massive Dissemination of Methicillin ResistantStaphylococcus aureusin Bloodstream Infections in a High MRSA Prevalence Country: Establishment and Diversification of EMRSA-15

“…8,10,19,22,43 Furthermore, EMRSA-15 has also been reported in other non-European countries, such as USA, 15 India, 14 and Malaysia; 20 however, in these locations it was not the predominant clone. EMRSA-15 has been recently reported to be found in high rates also in community settings in Portugal, suggesting the spillover of the clone from nosocomial settings into the community.…”

“…21,37 Recently, some European countries were able to stabilize and reduce MRSA prevalence through the introduction of infection control strategies; however, the Portuguese scenario remains unchanged. 19 MRSA evolution in Portugal has been characterized by the occurrence of clonal replacements every 10 years. The last national surveillance study for the characterization of the S. aureus clones circulating in Portuguese hospital was performed in 2006, and EMRSA-15 was then found to be the dominant clone.…”

ZnO Nanoparticles Impose a Panmetabolic Toxic Effect Along with Strong Necrosis, Inducing Activation of the Envelope Stress Response in Salmonella enterica Serovar Enteritidis

“…T he emergence of multidrug-resistant bacteria, including bacteria with resistance to multiple new antibiotics, has become a major public health problem worldwide (1,2). The importance of this growing problem can be illustrated using vancomycin-resistant enterococci as an example.…”