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Virulence determinants and biofilm formation in clinical isolates of Enterococcus: A cross-sectional study
Authors: Fatemeh Shahi1,2,3, Hajar Hamidi2 , Saeed Khoshnood4 , Golshan Mehdipour2 , Aram Asarezadegan Dezfouli2 , Ahmad Farajzadeh Sheikh2,3
Number of views: 207
Objective: To evaluate the relationship between biofilm formation
and incidence of virulence determinants in clinical isolates of
Enterococcus.
Methods: In this cross-sectional study, the clinical isolates of
Enterococcus strains were collected from the university teaching
hospitals in Ahvaz, Iran from June 2017 to June 2018. Then, the
prevalence of Enterococcus species, antibiotic resistance, virulence
factors, and biofilm-producing ability were determined.
Results: Of the 119 tested isolates, 17 (14.3%) were Enterococcus
faecalis, 72 (60.5%) were Enterococcus faecium and 30 (25.2%)
were other Enterococcus spp. Gelatinase was detected in 97 (81.5%)
isolates, enterococcal surface protein in 41 (34.5%) isolates, serine
protease in 39 (32.8%) cases, accessory colonization factor in 111
(93.3%) cases and pathogenicity islands in 17 (14.3%) cases. The
biofilm formation ability was observed in 75 (63.0%) of all isolates
and the association between the presence of enterococcal surface
protein gene and biofilm formation was statistically significant.
Higher resistance to vancomycin, gentamycin, and teicoplanin was
indicated in Enterococcus faecium with 81.8%, 58.4%, and 85.7%
resistance rate, respectively. All Enterococcus faecalis isolates were
sensitive to teicoplanin and vancomycin.
Conclusions: The presence of antibiotic-resistance with several
virulence factors in Enterococcus spp has become a concern. High
prevalence of enterococcal surface protein gene among biofilmproducing isolates suggests a potential relation between biofilm
formation and the enterococcal surface protein gene, and further
studies are needed to identify the mechanism of biofilm inhibition.