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Interactive data visualizations of antibiotic use and resistance in North America and Europe
The Changing Epidemiology of Methicillin-Resistant Staphylococcus aureus in the United States: A National Observational Study
How has the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) changed in recent years?
The growth of MRSA-related hospitalizations was stagnant between 2005 and 2009. Community-associated infections peak in the summer, likely due to seasonal antibiotic overuse. Read more about the findings in our press release.
Normally found on human skin, Staphylococcus aureus can infect wounds and cause life-threatening conditions such as sepsis and pneumonia. Strains of methicillin-resistant S. aureus (MRSA) fail to respond to commonly used antibiotics, making infections more expensive and difficult to treat. Prior studies report MRSA kills approximately 20,000 people each year and increases hospital costs by between $3,000 to more than $35,000.
The new study has several implications for public health and future studies. First, we need better surveillance to address emerging threats before they reach the epidemic proportions of MRSA. Secondly, the continued prevalence of CA-MRSA is worrying and suggests a need for more coordinated campaigns for infection control and judicious antibiotic use in communities as well as hospitals. Finally, more research is needed to better understand changing MRSA trends and apply these lessons to other emerging infections, to explore the interaction between community- and hospital-associated strains, and to aid the development of a staph vaccine.
Methicillin-resistant Staphylococcus aureus (MRSA) can cause major illness and death and impose serious
economic costs on patients and hospitals. Community-associated MRSA (CA-MRSA) is a growing problem in
US hospitals, which are already dealing with high levels of hospital-associated MRSA (HA-MRSA), but little is
known about how patient age and seasonal differences in the incidence of these 2 forms of MRSA affect the
epidemic. By using national data on hospitalizations and antibiotic resistance, we estimated the magnitude and
trends in annual S. aureus and MRSA hospitalization rates from 2005–2009 by patient age, infection type, and
resistance phenotype (CA-MRSA vs. HA-MRSA). Although no statistically significant increase in the hospitalization
rate was seen over the study period, the total number of infections increased. In 2009, there were an estimated
463,017 (95% confidence interval: 441,595, 484,439) MRSA-related hospitalizations at a rate of 11.74
(95% confidence interval: 11.20, 12.28) per 1,000 hospitalizations. We observed significant differences in infection
type by age, with HA-MRSA–related hospitalizations being more common in older individuals. We also
noted significant seasonality in incidence, particularly in children, with CA-MRSA peaking in the late summer
and HA-MRSA peaking in the winter, which may be caused by seasonal shifts in antibiotic prescribing patterns.
age differences; community-acquired infection; cross infection; methicillin-resistant Staphylococcus aureus;