MRSA Research Center

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MRSA History Timeline: 1959–2017

Methicillin, the first beta-lactamase-resistant penicillin, was licensed in England

First MRSA isolates identified in a British study

Infrequent hospital outbreaks of MRSA in Western Europe and Australia

First hospital outbreak of MRSA in the United States at the Boston City Hospital, Massachusetts

1968–mid 1990s

  • MRSA gradually recognized as an endemic pathogen in hospitals, especially in large urban university hospitals
  • Percent of Staphylococcus aureus infections in hospitalized patients that were caused by MRSA increased slowly but steadily

Large outbreak of MRSA infections among injecting drug users in Detroit, Michigan

Identification of the mecA gene encoding the low affinity penicillin binding protein that confers methicillin resistance
PMID: Matsuhashi et al.,
PMID 3638304

Late 1980s–1990s
Outbreaks of MRSA noted in Australia among Aboriginal populations with no exposure to hospitals

The first clinical VISA isolate of S. aureus with reduced susceptibility to vancomycin was reported from Japan

MRSA is associated with the deaths of 4 children in Minnesota and North Dakota

1998–2008: The CA-MRSA Epidemic Decade
While rates of HA-MRSA (healthcare-associated MRSA) infection remained stable, rates of CA-MRSA (community-associated MRSA) increased

Scattered reports of CA-MRSA infections in children in the United States

*Comparing 2 periods—1993-1995 and 1995-1997—among children with no risk factors for health care exposure, there was a 25-fold increase in the rate of hospitalizations due to MRSA. (See the 2/25/98 issue of JAMA and the accompanying press release.)

*First reports of healthy, young children dying of severe MRSA infections

The first sequence of SCCmec was published, the mobile genetic element that carries mecA in the staphylococcal chromosome
Ito et al.,
PMID: 10817707

Shift from USA400 to USA300 as predominant strain of CA-MRSA in the United States

The first whole genome sequence of MRSA was published (in the first VISA strain)
Kuroda et al.,
PMID: 11418146

The first documented case of infection caused by vancomycin-resistant S. aureus (VRSA) (vancomycin MIC > or = 32 microg/mL) in a patient in the United States
PMID: 12139181

*SCCmec IV recognized
Major groups of MRSA defined by the U.S. Centers for Disease Control and Prevention (USA100, USA200, USA300, ...USA1000)

In large studies, correlations made between different MRSA genotypes and specific clinical syndromes

CA-MRSA risk factors identified to date include: athletes, military recruits, incarcerated people, emergency room patients, urban children, HIV patients, men who have sex with men, indigenous populations

Whole genome sequence of USA300 was published
Diep et al.,
PMID: 16517273

JAMA-published study showed that invasive MRSA infection affects certain populations disproportionately and that it is a major public health problem primarily related to healthcare but no longer confined to intensive care units, acute care hospitals, or any healthcare institution.  This study estimated that close to 95,000 invasive MRSA infections occurred in the United States in 2005; these infections were associated with death in approximately 19,000 cases.  (See the 10/17/07 issue of JAMA for the full article.) 

JAMA-published study showed that from 2005 through 2008, in 9 diverse metropolitan areas, rates of invasive healthcare-associated MRSA infections decreased among patients with healthcare-associated infections that began in the community and also decreased among those with hospital-onset invasive disease.  (See the 8/11/10 issue of JAMA for the full article.) 

*Infection Control and Hospital Epidemiology-published study showed MRSA infections doubled at academic medical centers in the U.S. between 2003 and 2008.  Hospitalizations increased from about 21 out of every 1,000 patients hospitalized in 2003 to about 42 out of every 1,000 in 2008, or almost 1 in 20 patients.  The findings run counter to CDC’s reporting that MRSA cases in hospitals have been declining.  The CDC study, however, looked only at cases of invasive MRSA—infections found in the blood, spinal fluid, or deep tissue; it excluded infections of the skin, which the Infection Control and Hospital Epidemiology-published study includes.  Researchers attribute much of the overall increase to community-associated infections—those that are contracted outside the healthcare setting.  (See the August 2012 issue of Infection Control and Hospital Epidemiology for the full article.)   

2012: MRSA infections cause people to go to hospitals; hospital stays less commonly cause MRSA infections

  1. CA-MRSA has confusing criteria because CA-MRSA strains commonly cause infections in healthcare settings.
  2. CA-MRSA infections now common in most U.S. cities.
  3. CA-MRSA infection and asymptomatic colonization remain less common outside the U.S.

* Work at the University of Chicago shows that USA300, the American epidemic strain, does not elaborate capsular polysaccharide in vitro or in vivo. This finding provides one important reason why vaccines containing the capsular polysaccharide are unlikely to work when USA300 causes the infection.
* University of Chicago-led findings