Methicillin-resistant Staphylococcus aureus bacteraemia in Hong Kong

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Hospital Epidemiology

Background:

• Hospital-acquired infections pose a significant challenge in healthcare settings.
• The emergence and spread of antibiotic-resistant bacteria, such as MRSA, are a growing public health concern.
• Understanding the epidemiology and clinical impact of MRSA bacteraemia is crucial for effective infection control.

Purpose of the Study:

• To investigate the incidence and characteristics of hospital-acquired Staphylococcus aureus bacteraemia.
• To determine the proportion of methicillin-resistant Staphylococcus aureus (MRSA) among these infections.
• To analyze the clinical outcomes, risk factors, and treatment efficacy for MRSA bacteraemia.

Main Methods:

• Prospective surveillance of hospital-acquired bacteraemia over 22 months.
• Analysis of Staphylococcus aureus isolates, including methicillin resistance and plasmid profiling.
• Comparison of clinical data, patient demographics, and treatment outcomes between MRSA and methicillin-sensitive S. aureus (MSSA) bacteraemia.

Main Results:

• MRSA accounted for 46% (26/56) of hospital-acquired S. aureus bacteraemias within the first 22 months.
• MRSA bacteraemia cases showed a significant association with severe underlying disease, poor prognosis, prolonged hospitalization, and prior aminoglycoside use.
• Patients with MRSA bacteraemia experienced longer hospital stays, higher antimicrobial costs, and increased mortality compared to MSSA cases.

Conclusions:

• MRSA rapidly emerged as a significant cause of hospital-acquired bacteraemia shortly after hospital opening.
• MRSA infections are associated with poorer clinical outcomes and increased healthcare resource utilization.
• Vancomycin demonstrated a lower mortality rate in invasive MRSA infections, supporting its role as a current treatment of choice.