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Capsule locus polymorphism among distinct lineages of Enterococcus faecalis isolated from canals of root-filled teeth
Ericka T Pinheiro1, Pâmela P Penas, Marcos Endo
1Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. erickapinheiro@yahoo.com.br
Introduction:
Although Enterococcus faecalis is a member of the normal microbiota, it is also a major cause of nosocomial infections. Some strains of E. faecalis produce capsule, which contributes to pathogenesis through evasion of host defenses, and its production is dependent on the capsule (cps) operon polymorphism. This study investigated cps locus polymorphism in distinct lineages of E. faecalis isolated from canals of root-filled teeth with periapical lesions.
Methods:
Twenty-two E. faecalis isolates were evaluated regarding the cps operon polymorphism and genetic diversity. The 3 known CPS types were determined by polymerase chain reaction. This information was correlated with multilocus sequence typing data, which were used to define genetic lineages.
Results:
cpsA and cpsB were the only detected genes within the cps operon in 62.5% of E. faecalis strains (14/22), indicative of genotype CPS 1, which lacks capsule expression. The essential genes in the cps operon for capsule production were detected in the remaining strains, whereas 3 belonged to genotype CPS 5 and 5 strains to genotype CPS 2. A total of 14 sequence types (STs) were resolved in 22 E. faecalis isolates. Comparison with the E. faecalis international multilocus sequence typing database revealed that 9 STs were previously found, and that the 5 STs were novel.
Conclusions:
Certain E. faecalis genotypes from canals of root-filled teeth with periapical lesions belong to lineages associated with capsule expression and production of multiple virulence factors, which might account for their increased pathogenic potential.
Insights
Certain Enterococcus faecalis strains from root canals show capsule gene variations linked to increased virulence. This study explored capsule operon polymorphism in E. faecalis lineages from periapical lesions.
Area of Science:
- Microbiology
- Genetics
- Oral Health
Background:
- Enterococcus faecalis is a common nosocomial pathogen.
- Capsule production in E. faecalis aids in evading host defenses.
- Capsule operon (cps) polymorphism influences capsule expression and pathogenicity.
Purpose of the Study:
- Investigate capsule operon polymorphism in E. faecalis strains from root-filled teeth with periapical lesions.
- Determine the genetic diversity and lineages of these isolates.
- Correlate capsule genotypes with genetic lineages and potential virulence.
Main Methods:
- Analyzed 22 E. faecalis isolates from root canals.
- Determined capsule (CPS) types using polymerase chain reaction (PCR).
- Employed multilocus sequence typing (MLST) to define genetic lineages.
Main Results:
- CPS genotype 1 (lacking capsule) was found in 62.5% of strains.
- CPS genotypes 2 and 5 were identified in other strains.
- MLST revealed 14 sequence types (STs), including 5 novel STs, and identified distinct E. faecalis lineages.
Conclusions:
- E. faecalis genotypes from root canals can exhibit capsule expression.
- These genotypes are associated with lineages producing multiple virulence factors.
- This suggests an increased pathogenic potential contributing to periapical lesions.
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