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Genotypic and phenotypic diversity in Enterococcus faecalis: is agar invasion a pathogenicity score?
F Cafini1, F Gómez-Aguado, M T Corcuera
1Fabio Cafini, Medicine Department - Microbiology Area, School of Medicine, Complutense University, Avda Complutense s/n, 28040, Madrid, Spain. fcafini@med.ucm.es.
Summary
This study found that Enterococcus faecalis strains from blood samples frequently exhibit agar invasion, a virulence trait that decreases with lab adaptation. This highlights the adaptability of bacterial virulence factors.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Enterococcus faecalis is an opportunistic pathogen.
- Virulence factors contribute to E. faecalis pathogenicity.
- Understanding virulence traits is crucial for infection control.
Purpose of the Study:
- Analyze genotypic and phenotypic virulence traits in E. faecalis.
- Evaluate the agar invasion phenotype in clinical isolates.
- Correlate virulence factors with clinical origin.
Main Methods:
- Analyzed 79 E. faecalis isolates from invasive and non-invasive sources.
- Detected virulence genes (cylA, gelE, esp, asa1, efaA, ace) via PCR.
- Assessed phenotypic traits: gelatinase activity, haemolysin production, biofilm formation, and agar invasion.
Main Results:
- All isolates possessed at least one virulence determinant.
- 95.5% of isolates from haematologic samples were positive for agar invasion.
- Agar invasiveness significantly reduced in strains after serial passages in the lab.
Conclusions:
- High prevalence of agar invasion observed in E. faecalis from haematologic samples.
- Agar invasiveness is a modifiable phenotype, decreasing with laboratory adaptation.
- Culture conditions can influence bacterial virulence factor expression.
