Screening methods for meticillin-resistant Staphylococcus aureus.

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Quality Assurance in Healthcare

Background:

• External Quality Assessment (EQA) is crucial for laboratory performance monitoring.
• The UK National External Quality Assessment Service (UK NEQAS) provides specimens for EQA.
• Meticillin-resistant Staphylococcus aureus (MRSA) poses a significant public health threat, necessitating accurate detection.

Purpose of the Study:

• To evaluate the suitability of a freeze-dried specimen format for EQA of MRSA screening methods.
• To review the various methods employed by laboratories for MRSA screening.
• To assess the homogeneity of the distributed MRSA specimens.

Main Methods:

• Distribution of freeze-dried MRSA-containing specimens by UK NEQAS to participating laboratories.
• Analysis of reported results from 714 laboratories for MRSA presence and quantification.
• Categorization and review of the different MRSA screening approaches used by laboratories.

Main Results:

• A high proportion of laboratories (678/714) reported the presence of MRSA.
• Specimen homogeneity was confirmed with mean and median colony counts indicating consistent distribution.
• Four main categories of MRSA screening methods were identified: liquid culture, direct plating on conventional media, direct plating on chromogenic media, and rapid methods.

Conclusions:

• The freeze-dried specimen format is suitable for EQA of MRSA screening.
• Laboratories utilize a wide array of methods for MRSA detection, often employing multiple techniques.
• Standardization of MRSA screening protocols across the UK is recommended to improve consistency and accuracy.