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Published on: May 4, 2018
Hidden transmissions of Pseudomonas aeruginosa ST111 -the importance of continuous molecular surveillance
Jasmin Kaur Jasuja1, Eva-Maria Klupp2, Martin Aepfelbacher3
1Department for Infection Prevention and Control, Institute for Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany. j.jasuja@uke.de.
Background:
A series of transmission of Pseudomonas aeruginosa ST111 blaVIM-2, previously undetected by standard surveillance, was discovered in a tertiary care hospital in Northern Germany through molecular genetic monitoring. Hence, environmental sampling was initiated to find the source of infection.
Methods:
First, routine epidemiological data ruled out patient-to-patient transmission and two initial diagnoses were assessed as externally acquired. After the discovery of the highly related cluster by whole genome sequencing, a more detailed epidemiological analysis was carried out, including previous hospitalizations. An environmental investigation was initiated due to a possible connection of transmissions with an intensive care unit.
Results:
Between 2018 and 2023 16 clinical isolates of Pseudomonas aeruginosa ST111 blaVIM-2 were identified of which 12 isolates belonged to ST111 carrying an In59-like integron. Routine whole-genome sequencing of carbapenem resistant P. aeruginosa identified a highly related cluster (maximum of three allelic differences) of high-risk ST111 isolates in ICU patients over five years, confirming sink-to-patient transmission associated to sink drains in two ICU rooms. In initial routine epidemiological categorization of these highly related isolates four isolates were categorized as possible nosocomial acquisition without direct epidemiological link to other patients, whereas two isolates were categorized as 'externally acquired'.
Conclusions:
This finding highlights the ability of high-risk clone ST111 to persist in hospital environments and emphasizes the importance of integrating molecular surveillance with routine epidemiology to uncover hidden transmissions. In this case, the frequent detection of the ST111 high-risk clone led to targeted environmental sampling, uncovering a prolonged outbreak that had gone unnoticed by conventional surveillance. The clone was eliminated from the ward during a reconstruction project.
Insights
A high-risk Pseudomonas aeruginosa ST111 clone carrying blaVIM-2 carbapenemase was found to persist in hospital sink drains, causing undetected transmissions. Molecular surveillance identified and helped eliminate this persistent bacterial threat.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Undetected transmissions of Pseudomonas aeruginosa ST111 blaVIM-2 were identified in a German hospital via molecular genetic monitoring.
- Standard surveillance methods failed to detect this carbapenem-resistant *P. aeruginosa* strain.
Purpose of the Study:
- To investigate the source of *Pseudomonas aeruginosa* ST111 blaVIM-2 transmissions.
- To determine the role of the hospital environment in the spread of this high-risk clone.
Main Methods:
- Initial epidemiological data ruled out patient-to-patient transmission.
- Whole genome sequencing (WGS) identified a highly related cluster of *P. aeruginosa* ST111 isolates.
- Environmental sampling targeted intensive care unit (ICU) sink drains.
Main Results:
- Sixteen clinical isolates of *Pseudomonas aeruginosa* ST111 blaVIM-2 were identified between 2018 and 2023.
- WGS revealed a highly related cluster of ST111 isolates in ICU patients over five years.
- Sink drains in two ICU rooms were confirmed as the source of sink-to-patient transmission.
Conclusions:
- High-risk clone ST111 can persist undetected in hospital environments, particularly associated with sink drains.
- Integrating molecular surveillance with routine epidemiology is crucial for uncovering hidden hospital-acquired infections.
- Targeted environmental sampling identified a prolonged outbreak, leading to successful elimination of the clone.
