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

摘要

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 biofilm-producing 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.