Decline and fall of epidemic meticillin-resistant Staphylococcus aureus-16

Staphylococcus aureus Bacteremia at 5 US Academic Medical Centers, 2008-2011: Significant Geographic Variation in Community-Onset Infections

“…Driven by emergence of USA300, the incidence of MRSA infections rose dramatically in the early 2000s. In 2000, the Centers for Disease Control and Prevention (CDC) estimated that there were >30 000 hospitalizations for MRSA bacteremia [15]; however, more recent published reports have described declines in invasive MRSA infection rates, particularly in healthcare settings [16][17][18][19][20]. In the United States and the United Kingdom, the decline in MRSA bacteremia rates appears to have preceded enhanced infection prevention efforts in hospitals [21].…”

Genome-wide single nucleotide polymorphism-based assay for high-resolution epidemiological analysis of the methicillin-resistant Staphylococcus aureus hospital clone EMRSA-15

“…In the past 20 years, two major clones of HA‐MRSA defined by their pulsed‐field gel electrophoresis (PFGE) profiles have dominated in the UK; namely epidemic methicillin‐resistant S. aureus 15 (EMRSA‐15) and EMRSA‐16, corresponding to sequence type 22 (ST22) and ST36 as determined by multilocus sequence typing. However, the prevalence of EMRSA‐16 has declined in the UK since 2001 and in 2011 the Scottish MRSA Reference Laboratory reported that EMRSA‐15 and EMRSA‐16 accounted for 81% and 8%, respectively, of MRSA infections in Scottish healthcare centres . The reason(s) for the decline of EMRSA‐16 are uncertain but may be due to overall reduced fitness of EMRSA‐16 strains resulting from the energy burden of increasing antibiotic resistance, with a background of improved hygiene for infection control in hospitals .…”