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Clinical outbreak of linezolid-resistant Staphylococcus aureus in an intensive care unit
Miguel Sánchez García1, María Angeles De la Torre, Gracia Morales
1Intensive Care Department, Hospital Clínico San Carlos and Universidad Complutense, 28040 Madrid, Spain. msanchezga.hcsc@salud.madrid.org
Context:
Linezolid resistance is extremely uncommon in Staphylococcus aureus.
Objective:
To report an outbreak with linezolid and methicillin-resistant S. aureus (LRSA) in an intensive care department and the effective control measures taken.
Design, Setting, And Patients:
Outbreak study of consecutive critically ill patients colonized and/or infected with LRSA at an intensive care department of a 1000-bed tertiary care university teaching hospital in Madrid, Spain. Patients were placed under strict contact isolation. Daily updates of outbreak data and recommendations for the use of linezolid were issued. Extensive environmental sampling and screening of the hands of health care workers were performed.
Main Outcome Measures:
Linezolid use and clinical and epidemiological characteristics and outcomes using minimal inhibitory concentrations, pulsed-field gel electrophoresis, and polymerase chain reaction of LRSA isolates.
Results:
Between April 13 and June 26, 2008, 12 patients with LRSA were identified. In 6 patients, LRSA caused ventilator-associated pneumonia and in 3 patients it caused bacteremia. Isolates were susceptible to trimethoprim-sulfamethoxazole, glycopeptides, tigecycline, and daptomycin. Genotyping identified 1 predominant clone and 3 other types. Cfr-mediated linezolid resistance was demonstrated in all isolates. Potential hospital staff carriers and environmental samples were negative except for one. Six patients died, 5 of them in the intensive care unit, with 1 death attributed to LRSA infection. Linezolid use decreased from 202 defined daily doses in April 2008 to 25 defined daily doses in July 2008. Between July 2008 and April 2010, no new cases have been identified in the weekly surveillance cultures or diagnostic samples.
Conclusions:
The first clinical outbreak, to our knowledge, with LRSA mediated by the cfr gene developed at our center, was associated with nosocomial transmission and extensive usage of linezolid. Reduction of linezolid use and infection-control measures were associated with the termination of the outbreak.
Insights
An outbreak of linezolid-resistant Staphylococcus aureus (LRSA) occurred in an ICU, driven by extensive linezolid use. Strict infection control and reduced linezolid prescriptions successfully terminated the LRSA outbreak.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Hospital Epidemiology
Background:
- Linezolid resistance in Staphylococcus aureus is rare.
- The emergence of linezolid-resistant S. aureus (LRSA) poses a significant clinical challenge.
Purpose of the Study:
- To report the first clinical outbreak of LRSA mediated by the cfr gene.
- To describe the control measures implemented during the outbreak.
Main Methods:
- An outbreak study was conducted in an intensive care department.
- Methods included patient isolation, environmental sampling, and molecular genotyping of LRSA isolates.
- Linezolid usage and patient outcomes were meticulously tracked.
Main Results:
- Twelve patients were identified with LRSA, causing ventilator-associated pneumonia and bacteremia.
- All isolates exhibited cfr-mediated linezolid resistance.
- Implementation of infection control measures and reduced linezolid use led to the outbreak's termination, with no new cases identified subsequently.
Conclusions:
- The LRSA outbreak was linked to nosocomial transmission and extensive linezolid use.
- Effective control involved reducing linezolid prescriptions and implementing stringent infection control protocols.
- This highlights the importance of antimicrobial stewardship in preventing resistance.
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