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Izaskun Muruzábal-Lecumberri1, Cecilia Girbau, Andrés Canut
1Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Vitoria, Spain.
Abstract:
Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high-risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD-PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD-PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.
Insights
The dominant Enterococcus faecalis ST6 clone, frequently found in ICU patients, exhibits multidrug resistance and virulence genes. This highlights the need for strict surveillance to control its spread in healthcare settings.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Hospital Epidemiology
Background:
- Enterococcus faecalis (E. faecalis) is a significant cause of hospital-acquired infections, particularly in immunocompromised individuals.
- High-risk clonal complexes, like CC2, contribute to the dissemination of E. faecalis within healthcare environments.
- Selective decontamination of the digestive tract (SDD) is a strategy used in intensive care units (ICUs).
Purpose of the Study:
- To phenotypically and genotypically characterize E. faecalis isolates from ICU patients undergoing SDD.
- To identify the prevalence of specific E. faecalis clones and their associated virulence factors.
- To understand the genetic diversity and antimicrobial resistance patterns within these isolates.
Main Methods:
- Phenotypic analysis included antimicrobial susceptibility testing.
- Genotypic analysis involved identifying virulence genes, Random Amplified Polymorphic DNA-PCR (RAPD-PCR), and Multilocus Sequence Typing (MLST).
- Isolates were obtained from patients in the ICU undergoing SDD.
Main Results:
- The ST6 E. faecalis clone was highly prevalent (91.6%) among the studied isolates, indicating adaptation to the hospital environment.
- ST6 isolates displayed multidrug resistance and carried numerous putative virulence genes.
- Other detected clones included ST179 and ST191 (4.2% each).
- RAPD-PCR revealed genetic diversity within the ST6 clone and distinct profiles for ST179 and ST191.
Conclusions:
- The ST6 clone, part of the CC2 complex, shows high adaptability and prevalence in the hospital setting.
- The high prevalence of gentamicin-resistant ST6 strains may be linked to gentamicin use in SDD.
- Strict surveillance is crucial for the early detection and control of this clone to prevent its wider dissemination.
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