Risk factors for methicillin resistant Staphylococcus aureus: a multi-laboratory study.

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Public Health

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant healthcare challenge.
• Understanding the relationship between antimicrobial use and MRSA is crucial for infection control.

Purpose of the Study:

• To investigate the dose-response relationship between antimicrobial agent prescriptions and MRSA infection or colonization.
• To identify risk factors for MRSA, considering healthcare facility stays.

Main Methods:

• A multi-center retrospective study involving 6844 patients across 17 clinical laboratories in Belgium (2005).
• Data on microbiological results, individual antimicrobial consumption, and health insurance information were analyzed.
• Multivariate logistic regression identified risk factors associated with MRSA colonization/infection.

Main Results:

• MRSA was predominantly associated with infection (over 97%) rather than colonization.
• Significant risk factors for MRSA included admission to long-term care settings, antibiotic prescription via hospital pharmacy, and older age (55+ and 15-54 years).
• A dose-response relationship was observed between antimicrobial consumption per defined daily dose (DDD) and MRSA risk.

Conclusions:

• A direct dose-response relationship exists between MRSA and antimicrobial consumption at the individual patient level, with a 25-40% increased risk per day of use.
• Specific healthcare settings and patient age are significant factors influencing MRSA status.