Methicillin-resistant Staphylococcus aureus in Western Australia, 1983-1992

Area of Science:

• Infectious Diseases
• Microbiology
• Public Health Surveillance

Background:

• Western Australia (WA) implemented a statewide screening program to prevent the establishment of imported methicillin-resistant Staphylococcus aureus (MRSA).
• Recent increases in MRSA notifications in WA prompted a review of surveillance data from 1983 to 1992.

Purpose of the Study:

• To analyze the age and sex distribution of MRSA cases in WA.
• To examine temporal trends and geographical variations in MRSA notification rates.
• To investigate changes in antimicrobial resistance patterns of MRSA strains.

Main Methods:

• Retrospective analysis of MRSA surveillance data from 1983 to 1992.
• Examination of notification rates by age, sex, and geographical region.
• Classification of MRSA strains based on antimicrobial resistance patterns.

Main Results:

• A total of 631 MRSA notifications were recorded between 1983 and 1992, with a notable increase by 1992.
• Peak age groups for MRSA notifications included 0-9, 20-39 (predominantly females, likely nursing staff), and 60-79 years.
• The Kimberley region initially had the highest rates, but all regions saw increased notifications in 1992.
• Two MRSA groups were identified: multiresistant imported strains and a less resistant 'WA MRSA' strain.
• WA MRSA, originating in the Kimberley, spread throughout the state, with its proportion increasing significantly since 1989.

Conclusions:

• The study identified distinct demographic patterns and geographical spread of MRSA in Western Australia.
• The emergence and increasing prevalence of the local WA MRSA strain indicate a shift in the MRSA landscape.
• Findings underscore the importance of continued surveillance and adaptive strategies to manage MRSA in the region.