Related Experiment Video
Updated: Aug 21, 2026
A Neonatal Imaging Model of Gram-Negative Bacterial Sepsis
Published on: August 12, 2020
Molecular epidemiology of Serratia marcescens outbreaks in two neonatal intensive care units
Vladana Milisavljevic1, Fann Wu, Elaine Larson
1Department of Pediatrics, School of Nursing, Columbia University, New York, New York, USA.
Objective:
Serratia marcescens can cause serious infections in patients in neonatal intensive care units (NICUs), including sepsis, pneumonia, urinary tract infection, and conjunctivitis. We report the utility of genetic fingerprinting to identify, investigate, and control two distinct outbreaks of S. marcescens.
Design:
An epidemiologic investigation was performed to control two clusters of S. marcescens infections and to determine possible routes of transmission. Molecular typing by pulsed-field gel electrophoresis determined the relatedness of S. marcescens strains recovered from neonates, the environment, and the hands of healthcare workers (HCWs).
Setting:
Two geographically distinct level III-IV NICUs (NICU A and NICU B) in two university-affiliated teaching hospitals in New York City.
Results:
In NICU A, one major clone, "F," was detected among isolates recovered from four neonates and the hands of one HCW. A second predominant clone, "A," was recovered from four sink drains and one rectal surveillance culture from an asymptomatic neonate. In NICU B, four neonates were infected with clone "D," and three sink drains harbored clone "H." The attributable mortality rate from bloodstream infections was 60% (3 of 5 infants). The antimicrobial susceptibilities of clone F strains varied for amikacin, cefepime, and piperacillin/tazobactam.
Conclusions:
S. marcescens causes significant morbidity and mortality in preterm neonates. Cross-transmission via transient hand carriage of a HCW appeared to be the probable route of transmission in NICU A. Sinks did not harbor the outbreak strains. Antimicrobial susceptibility patterns did not prove to be an accurate predictor of strain relatedness for S. marcescens.
Insights
Genetic fingerprinting identified two distinct Serratia marcescens outbreaks in neonatal intensive care units (NICUs). Healthcare worker hand carriage was a likely transmission route, highlighting the need for stringent infection control in NICUs.
Area of Science:
- Infectious Diseases
- Neonatology
- Molecular Epidemiology
Background:
- Serratia marcescens poses a significant threat to vulnerable neonates in NICUs, causing severe infections like sepsis and pneumonia.
- Outbreaks of S. marcescens in NICUs can lead to substantial morbidity and mortality among preterm infants.
Purpose of the Study:
- To investigate and control two distinct outbreaks of Serratia marcescens in neonatal intensive care units.
- To determine the utility of genetic fingerprinting in identifying outbreak sources and transmission routes of S. marcescens.
Main Methods:
- Epidemiologic investigation to control S. marcescens clusters and identify transmission pathways.
- Pulsed-field gel electrophoresis (PFGE) used for molecular typing of S. marcescens strains from neonates, environment, and healthcare workers (HCWs).
- Study conducted in two geographically distinct level III-IV NICUs in New York City.
Main Results:
- In NICU A, clone "F" linked to neonates and HCW hands; clone "A" found in sink drains.
- In NICU B, clone "D" infected neonates, and clone "H" detected in sink drains.
- Attributable mortality from bloodstream infections was 60%; antimicrobial susceptibility patterns were inconsistent predictors of strain relatedness.
Conclusions:
- Serratia marcescens infections contribute significantly to morbidity and mortality in preterm neonates.
- Cross-transmission via HCW transient hand carriage was the probable route in NICU A; sinks were not implicated as sources.
- Antimicrobial susceptibility is not a reliable indicator for S. marcescens strain relatedness during outbreaks.
Related Concept Videos
01:25Clinical Significance of Antibiotic Resistance
01:25Mechanism of Antibiotic Resistance in MRSA
01:23Investigation of Disease Outbreaks
01:22Healthcare Associated Infections II: Preventive Measures
The best practices for preventing healthcare-associated infections include hand hygiene, patient risk...