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Serratia marcescens nosocomial outbreak due to contamination of hexetidine solution
C Bosi1, A Davin-Regli, R Charrel
1Laboratoire de Bactériologie, Hygiène et Epidémiologie Hospitalières, Hôpitaux-Sud, Marseille, France.
Abstract:
During a 10-week period, 16 patients in a neurosurgery intensive care unit were involved in an outbreak of Serratia marcescens. The epidemic strain was found in several flasks of 1:4 diluted hexetidine solution, an antiseptic used for patient mouth washing. Testing of the bactericidal activity of the diluted antiseptic revealed that all the epidemic strains were able to grow in the diluted antiseptic solution. Strains isolated from clinical samples and from the antiseptic solution were compared by random amplification of polymorphic DNA. Epidemiologic typing data implicated the diluted antiseptic solution as the single source of this S. marcescens outbreak.
Insights
A Serratia marcescens outbreak in a neurosurgery ICU was traced to a diluted antiseptic mouthwash. The antiseptic failed to kill the bacteria, allowing the outbreak to spread among 16 patients.
Area of Science:
- Infectious Diseases
- Microbiology
- Hospital Epidemiology
Background:
- Nosocomial infections pose significant risks in intensive care units.
- Serratia marcescens is an opportunistic pathogen frequently associated with healthcare-associated outbreaks.
- Antiseptics are critical for infection control but can be vulnerable to microbial contamination or reduced efficacy when diluted.
Purpose of the Study:
- To investigate the source and transmission of a Serratia marcescens outbreak in a neurosurgery intensive care unit.
- To evaluate the efficacy of a commonly used antiseptic solution against the epidemic strain.
- To identify the role of the antiseptic in facilitating the nosocomial outbreak.
Main Methods:
- Epidemiological investigation of 16 patient cases over a 10-week period.
- Microbiological analysis to identify Serratia marcescens in clinical samples and antiseptic solutions.
- Bactericidal activity testing of the diluted antiseptic against isolated strains.
- Molecular typing using random amplification of polymorphic DNA (RAPD) to compare strains.
Main Results:
- The epidemic strain of Serratia marcescens was isolated from clinical samples and from diluted hexetidine antiseptic solution flasks.
- All epidemic strains demonstrated the ability to grow in the 1:4 diluted hexetidine solution.
- Random amplification of polymorphic DNA analysis confirmed that strains from clinical sources and the antiseptic were epidemiologically linked.
- The diluted antiseptic solution was identified as the sole source of the Serratia marcescens outbreak.
Conclusions:
- Dilution of hexetidine antiseptic significantly compromised its bactericidal activity, enabling Serratia marcescens proliferation.
- Contaminated antiseptic solutions represent a potential reservoir for nosocomial pathogen transmission in healthcare settings.
- Strict adherence to antiseptic preparation protocols and regular quality control are essential for preventing outbreaks.