Methicillin-resistant Staphylococcus aureus DNA electrophoretic pattern: temporal changes in an endemic hospital...

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Genomic Epidemiology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat in hospital settings.
• Understanding the genetic diversity and transmission patterns of MRSA is crucial for infection control.

Purpose of the Study:

• To analyze the geographical and temporal distribution of MRSA strains using DNA profiling.
• To investigate the clonal evolution of MRSA in a Brazilian tertiary care university hospital.

Main Methods:

• Studied 99 MRSA samples from 89 patients between 1999 and 2004.
• Utilized pulsed-field gel electrophoresis (PFGE) with SmaI restriction endonuclease for genomic typing.
• MRSA strains were isolated from central venous catheters and bloodstream infections.

Main Results:

• Identified 26 distinct DNA PFGE profiles among the 99 MRSA strains.
• MRSA infections were detected a mean of 26 days post-hospital admission, with 57.6% of patients having recent hospitalizations.
• MRSA profiles clustered into three temporal clonal groups (I, II, III) and were homogeneously distributed across hospital wards.

Conclusions:

• MRSA strain profiles exhibited significant temporal changes, with clonal groups replacing one another over time.
• No specific hospital ward or area showed a predominance of any particular MRSA clonal group.
• The findings highlight the dynamic nature of MRSA epidemiology within hospitals.