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Burn and trauma units as sources of methicillin-resistant Staphylococcus aureus
L G Phillips1, J P Heggers, M C Robson
1Division of Plastic Surgery, University of Texas Medical Branch, Galveston 77550.
Abstract:
At the time that methicillin-resistant Staphylococcus aureus (MRSA) began to achieve clinical prominence, it was thought to be spread by exogenous vectors. Institution of rigorous infection control efforts, including isolation procedures, was found to have little effect on the frequency of MRSA colonization of burn wounds. It was later found that handwashing was sufficient to prevent cross-contamination. Subsequently, it has been shown that patients can be harboring MRSA at the time of admission to the burn unit and that multiple antimicrobial resistance can develop among organisms that reside in the patient through plasmid-mediated transfer of resistance genes. Excessive use of such agents as the synthetic penicillins and second- and third-generation cephalosporins has selected for the survival of these organisms. Currently, the only available agent for systemic treatment of MRSA infection is vancomycin, the use of which is expensive and associated with significant toxicity. Muciprocin is a topical antimicrobial that promises to be useful in the treatment of such infections. Other agents for systemic use are needed, since use of a single drug to combat MRSA infections seems likely to encourage the emergence of resistant organisms.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) spread is complex, involving patient harboring and gene transfer. New systemic treatments are crucial to combat MRSA and prevent further resistance development.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) emerged as a significant clinical threat.
- Initial control efforts focused on exogenous vectors and isolation, with limited success in burn wound colonization.
- Handwashing proved effective in preventing cross-contamination, but endogenous patient harboring and antimicrobial resistance gene transfer became recognized factors.
Purpose of the Study:
- To review the evolving understanding of MRSA transmission and resistance.
- To highlight the limitations of current MRSA treatment options.
- To emphasize the need for novel systemic antimicrobial agents against MRSA.
Main Methods:
- Review of historical and current literature on MRSA epidemiology and treatment.
- Analysis of factors contributing to MRSA colonization and resistance.
- Evaluation of existing and potential therapeutic strategies for MRSA infections.
Main Results:
- MRSA can be harbored by patients upon admission, complicating control.
- Plasmid-mediated gene transfer facilitates the development of multidrug resistance in MRSA.
- Extensive use of certain antibiotics (synthetic penicillins, cephalosporins) has selected for MRSA survival.
- Vancomycin remains the primary systemic agent but has limitations (cost, toxicity).
- Topical mupirocin shows promise for specific applications.
Conclusions:
- Understanding MRSA requires considering both exogenous and endogenous factors.
- The emergence of multidrug-resistant MRSA necessitates a re-evaluation of treatment strategies.
- Development of new systemic antimicrobial agents is critical to effectively manage MRSA infections and mitigate resistance.
- Over-reliance on single agents for MRSA treatment risks promoting further resistance.