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Published on: November 16, 2016
Understanding Serratia bockelmannii transmission during a neonatal intensive care unit outbreak: a combined
Kaisa Jaakkola1,2, Aurélie Fischer3,4, Louise Piquart3
1Institut Des Agents Infectieux, Hospices Civils de Lyon, Lyon, France. kaisa.jaakkola@fimnet.fi.
Background:
Serratia marcescens complex (SMC) is a group of opportunistic pathogens frequent in neonatal intensive care unit (NICU) outbreaks. We report a seven-month NICU outbreak of multidrug-resistant (MDR) SMC strain and assess the acquisition risk factors.
Methods:
Bacterial isolates were sequenced using Illumina technology and profiled for antimicrobial resistance (AMR). Cases (culture positive for SMC) were compared with birth date and ward-matched controls (SMC negative) to identify clinical and environmental factors associated with SMC acquisition.
Results:
A single strain of Serratia bockelmannii caused 42 cases from June 2022 to January 2023. All sequenced isolates (n = 49) carrued the same AMR genes, while the antibiogram (n = 32) assigned 15 strains as MDR, and 17 as non-MDR. The outbreak strain was recovered from ward surfaces and an analytical study revealed that beds used by several cases increased the acquisition odds by 3.27 (95%CI 1.71-8.77, p-value = 0.003) after adjusting for sex and length of stay.
Conclusions:
The genomic typing was pivotal in confirming clonality across S. bockelmannii isolates with varied antibiograms, and identifying the bacterial species. Serratia bockelmannii should be considered during SMC outbreaks. Incubator-related within-ward transmission highlights the need for tailored risk assessments and disinfection protocols to prevent pathogen transmission and to improve infection prevention protocols.
Insights
A seven-month neonatal intensive care unit outbreak was caused by Serratia bockelmannii. Shared incubator beds significantly increased acquisition risk, highlighting the need for enhanced infection control protocols.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Serratia marcescens complex (SMC) are opportunistic pathogens frequently implicated in neonatal intensive care unit (NICU) outbreaks.
- This study details a seven-month outbreak of multidrug-resistant (MDR) SMC within an NICU setting.
- It also investigates the risk factors associated with the acquisition of SMC.
Purpose of the Study:
- To report and analyze a prolonged NICU outbreak caused by a specific SMC strain.
- To identify clinical and environmental factors contributing to SMC acquisition.
- To assess the effectiveness of genomic typing in outbreak investigations.
Main Methods:
- Bacterial isolates underwent Illumina sequencing and antimicrobial resistance (AMR) profiling.
- A case-control study compared SMC-positive cases with matched SMC-negative controls.
- Statistical analysis identified risk factors for SMC acquisition, adjusting for relevant variables.
Main Results:
- A single strain of Serratia bockelmannii was responsible for 42 cases over seven months.
- While all isolates shared AMR genes, 15 were classified as MDR and 17 as non-MDR.
- Use of incubator beds previously occupied by cases increased acquisition odds by 3.27 (p=0.003).
Conclusions:
- Genomic typing confirmed clonality of Serratia bockelmannii isolates, aiding species identification during outbreaks.
- Serratia bockelmannii should be considered a significant pathogen in SMC outbreaks.
- Incubator-related transmission underscores the need for targeted disinfection and improved infection prevention strategies in NICUs.
