Related Experiment Video
Updated: Jul 5, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
Outbreak of multidrug-resistant Serratia marcescens infection in a neonatal intensive care unit
Lisa L Maragakis1, Amy Winkler, Margaret G Tucker
1Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA. lmaraga1@jhmi.edu
Background:
Serratia marcescens causes healthcare-associated infections and significant morbidity and mortality in neonatal intensive care units (NICUs). We report the investigation and control of an outbreak of multidrug-resistant (MDR) S. marcescens infection at an NICU.
Methods:
An outbreak investigation and a case-control study were undertaken at a 36-bed NICU in a tertiary care hospital in Baltimore, Maryland, for the period from October 2004 through February 2005. The outbreak investigation included case identification, review of medical records, environmental cultures, patient surveillance cultures, personnel hand cultures, and pulsed-field gel electrophoresis (PFGE). The case-control study included case identification and review of medical records. Infection control measures were implemented. Eighteen NICU neonates had cultures that grew MDR S. marcescens during the study period. The case-control study included 16 patients with the outbreak strain or an unidentified strain of MDR S. marcescens and 32 control patients not infected and/or colonized with MDR S. marcescens, treated in the NICU for at least 48 hours during the study period.
Results:
PFGE analysis identified a single strain of MDR S. marcescens that infected or colonized 15 patients. Two patients had unique strains, and 1 patient's isolate could not be subtyped. An unrelated MDR S. marcescens isolate was recovered from a sink drain. Exposure to inhalational therapy was an independent risk factor for MDR S. marcescens acquisition after adjusting for birth weight. Extensive investigation failed to reveal a point source for the outbreak.
Conclusion:
A single epidemic strain of MDR S. marcescens spread rapidly and threatened to become endemic in this NICU. Transient carriage on the hands of healthcare personnel or on respiratory care equipment was the likely mode of transmission. Cohorting patients and staff, at the cost of bed closures and additional personnel, interrupted transmission and halted the outbreak.
Insights
A multidrug-resistant Serratia marcescens outbreak in a NICU was investigated and controlled. Infection control measures, including cohorting, halted the rapid spread of this dangerous bacteria.
Area of Science:
- Infectious Diseases
- Healthcare Epidemiology
- Microbiology
Background:
- Serratia marcescens is a significant cause of healthcare-associated infections, particularly in neonatal intensive care units (NICUs).
- These infections lead to substantial morbidity and mortality among vulnerable neonates.
- This study details the investigation and containment of a multidrug-resistant (MDR) S. marcescens outbreak in an NICU setting.
Purpose of the Study:
- To investigate the epidemiology of a multidrug-resistant Serratia marcescens outbreak in a neonatal intensive care unit (NICU).
- To identify risk factors associated with the acquisition of MDR S. marcescens in neonates.
- To implement and evaluate infection control measures to control the outbreak.
Main Methods:
- An outbreak investigation and case-control study were conducted in a 36-bed NICU.
- Methods included case identification, medical record review, environmental and patient surveillance cultures, hand cultures, and pulsed-field gel electrophoresis (PFGE).
- Infection control interventions were implemented during the study period (October 2004–February 2005).
Main Results:
- PFGE identified a single MDR S. marcescens strain responsible for infecting or colonizing 15 patients.
- Exposure to inhalational therapy emerged as an independent risk factor for MDR S. marcescens acquisition.
- Despite extensive investigation, a definitive point source for the outbreak was not identified.
Conclusions:
- A single epidemic strain of MDR S. marcescens spread rapidly, posing an endemic threat to the NICU.
- Transient carriage on healthcare personnel hands or respiratory equipment was the probable transmission route.
- Patient and staff cohorting successfully interrupted transmission and controlled the outbreak, despite associated costs.
Related Concept Videos
01:25Clinical Significance of Antibiotic Resistance
01:25Mechanism of Antibiotic Resistance in MRSA
01:29Staphylococcal Skin Infections
01:22Healthcare Associated Infections II: Preventive Measures
The best practices for preventing healthcare-associated infections include hand hygiene, patient risk...
01:26Healthcare Associated Infections I: Iatrogenic, Exogenic and Endogenic
HAIs significantly increase the cost of health care. Extended stays in healthcare institutions, increased disability, increased costs of medications, including specialized antibiotics, and prolonged recovery times add to the patient's expenses and the healthcare institution and funding bodies. Common...
01:28Acute Pyelonephritis II: Diagnostic Studies and Management