Surveillance of hospital-acquired methicillin-resistant Staphylococcus aureus in South Australia

Area of Science:

• Infectious Disease Epidemiology
• Public Health Surveillance
• Healthcare-Associated Infections

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat in healthcare settings.
• Effective surveillance is crucial for understanding and controlling MRSA spread.
• Previous MRSA surveillance in South Australia was limited in scope.

Purpose of the Study:

• To expand the South Australian state-wide MRSA surveillance system.
• To introduce new indicators: estimated MRSA burden, morbidity, and acquisition.
• To stratify MRSA rates by intensive care unit (ICU) and non-ICU settings.

Main Methods:

• Implementation of a state-wide MRSA surveillance system in September 2001.
• Inclusion of three key indicators: burden, morbidity, and acquisition.
• Stratification of morbidity and acquisition rates into ICU and non-ICU categories.
• Development of a new monthly surveillance report with a focus on data confidentiality.

Main Results:

• State-wide MRSA burden (prevalence) ranged from 27.5 to 39.8 per 10,000 occupied bed days (OBDs) between September 2001 and March 2002.
• MRSA acquisition rates varied: 28.2–69.0 per 10,000 OBDs (ICU) and 6.3–10.1 per 10,000 OBDs (non-ICU).
• MRSA morbidity rates were observed at 12.9–43.1 per 10,000 OBDs (ICU) and 3.0–5.0 per 10,000 OBDs (non-ICU).

Conclusions:

• The expanded surveillance system provides valuable data on MRSA burden, acquisition, and morbidity in South Australia.
• Significant differences in MRSA rates exist between ICU and non-ICU settings.
• Hospitals should exercise caution when comparing rates, considering inter-institutional variations in MRSA burden and casemix complexity.