Virulence determinants and biofilm formation in clinical isolates of Enterococcus: A cross-sectional study

Shahi, Fatemeh; Hamidi, Hossein; Khoshnood, Saeed; Mehdipour, Golshan; Dezfouli, Aram Asarezadegan; Sheikh, Ahmad Farajzadeh

doi:10.4103/2221-6189.276079

Cited by 14 publications

(8 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…32 The high frequency of biofilm formation is also consistent with other studies. [33][34][35][36] In the current study, biofilm formation strength was significantly associated with the presence of gelE and sprE genes. Hancock and Perego, 14 as well as others, 33,37 reported earlier the importance of gelE for biofilm formation.…”

Section: Discussionsupporting

confidence: 48%

“…[33][34][35][36] In the current study, biofilm formation strength was significantly associated with the presence of gelE and sprE genes. Hancock and Perego, 14 as well as others, 33,37 reported earlier the importance of gelE for biofilm formation. On the other hand, Kafil and Mobarez 30 and Kart and Kuştimur 38 concluded that gelE gene presence had no effect on biofilm formation.…”

Section: Discussionsupporting

confidence: 48%

“…43 All the isolates in the current study harbored the ace gene, and such high frequency in isolates from UTI was reported in other studies. 30,33 Another factor associated with adherence is pili. Nallapareddy and colleagues reported that enterococci produce pili on their surface that help in bacterial adherence to host tissues and formation of biofilm.…”

Section: Discussionmentioning

confidence: 99%

“…48,49 Cytolysin expression was also found to be associated with increasing severity of infection. 50 Of note, previous studies 18,33,51 have analyzed virulence factor correlations in enterococci, in particular E. faecalis, isolated from Egyptian patients; however, the specificity of this work is that it solely focuses on E. faecalis samples from UTIs and that it calculates statistical associations between virulence genotypes and phenotypes, with particular emphasis on biofilm formation and adherence, in this type of clinically important infections.…”

Section: Discussionmentioning

confidence: 99%

“…Key virulence phenotypes were only tested in vitro, and the analysis was limited to UTIs to avoid redundancy with similar studies from the same geographical area. 18,33,51 Future studies will address the current limitations and expand the study scope: As more specimens become available, the statistical will be revisited and extended to reexamine findings with marginal or low significance. Additionally, an in vivo model, eg, the wax moth Galleria mellonella, represents an attractive, affordable model for enterococcal virulence that can be used to bolster in vitro findings.…”

Section: Discussionmentioning

confidence: 99%

See 4 more Smart Citations

Phenotype–Genotype Correlations and Distribution of Key Virulence Factors in Enterococcus faecalis Isolated from Patients with Urinary Tract Infections

Hashem¹,

Abdelrahman²,

Aziz³

2021

IDR

View full text Add to dashboard Cite

Background and Objective: Enterococcus faecalis can cause different nosocomial infections, especially urinary tract infection (UTI). Pathogenicity of E. faecalis is driven by various virulence factors; however, no specific genetic pattern is restricted to a particular type of infection. The current study aimed to investigate the correlation between different virulence factors in E. faecalis clinical isolates causing UTIs. Methods: We phenotypically analyzed 60 urinary isolates, identified as E. faecalis, for biofilm formation, gelatinase, protease and hemolytic activities by Crystal Violet assay, gelatin hydrolysis, casein hydrolysis and blood agar hemolysis assays, respectively. Additionally, we detected different genes associated with species identification, virulence phenotypes, adherence and quorum sensing by the polymerase chain reaction (PCR). The detected genes included D-alanine-D-alanine ligase (ddl), cytolysin (cyl), gelatinase (gelE), serine protease (sprE), faecal streptococci regulator locus genes (fsrA, fsrB, fsrC), pili (pil), adhesin to collagen of E. faecalis (ace) and aggregation substance (agg). Results: All isolates formed biofilms, mostly with strong to moderate ability. Although gelE was detected in 87% of the isolates, only 22% of the isolates had gelatinase activity. Similar phenotype-genotype incongruities were observed with hemolysis and casein hydrolysis activities, as the isolates that expressed these two phenotypes were fewer than those carrying the genes encoding them. Conclusion: A clear variability in virulence gene distribution among the isolates was observed, and no particular pattern was associated with UTI. Whereas all isolates carried at least ace and pil, whose products are involved in adherence, which is a virulence phenotype that is required for urinary colonization, six isolates carried the entire set of investigated genes. Statistical analysis of the results suggests cyl as a biomarker for hemolytic activity, fsrB as a diagnostic biomarker for the gelatinase activity, and gelE-sprE as predictors for biofilm formation strength in E. faecalis.

show abstract