Mortality in patients with meticillin-resistant Staphylococcus aureus bacteraemia, England 2004-2005

Area of Science:

• Infectious Diseases
• Epidemiology
• Public Health

Background:

• Meticillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired infections.
• MRSA bacteraemia is associated with high morbidity and mortality.
• Understanding the short-term risk of death is crucial for public health interventions.

Purpose of the Study:

• To determine the short-term risk of all-cause mortality in patients diagnosed with MRSA bacteraemia in England.
• To identify demographic and temporal factors associated with increased mortality risk.
• To estimate the population-level impact of MRSA bacteraemia on mortality.

Main Methods:

• Population-based cohort study using routine surveillance data from England (2004-2005).
• Matching MRSA-positive blood culture cases to the national registry of deaths.
• Analysis of case fatality rates within 7 and 30 days, stratified by age, sex, and season.

Main Results:

• Overall 7-day case fatality was 20%, rising to 38% within 30 days.
• Mortality risk was highest on the day of blood culture (4%) and increased with age (57% for ≥85 years within 30 days).
• Women had a higher 7-day fatality rate (OR 1.16), and case fatality peaked in winter.

Conclusions:

• MRSA bacteraemia is associated with a substantial short-term risk of death, particularly in the elderly and during winter.
• Age-standardised mortality ratios highlight the significant excess mortality associated with MRSA bacteraemia.
• While causality cannot be inferred, the study quantifies the mortality burden of MRSA bacteraemia.