Hashem Y.A.Amin H.M.Essam T.M.Yassin A.S.Aziz R.K.Department of Microbiology and ImmunologyFaculty of PharmacyBritish University in Egypt (BUE)Shorouk CityEgypt; Department of Microbiology and ImmunologyFaculty of PharmacyOctober University for Modern Sciences and Arts6 October CityEgypt; Department of Microbiology and ImmunologyFaculty of PharmacyCairo UniversityCairoEgypt2020-01-092020-01-09201720452322https://doi.org/10.1038/s41598-017-05901-0PubMed ID 28720810https://t.ly/rxxxRScopusMSA Google ScholarEnterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution in enterococcal genomes were identified, and the differentiating virulence genes were screened by polymerase chain reaction (PCR) in 31 of the clinical isolates. We found that detection of gelE in Enterococcus faecalis is not sufficient to predict gelatinase activity unless fsrAB, or fsrB alone, is PCR-positive (P = 0.0026 and 0.0012, respectively). We also found that agg is significantly enriched in isolates with medium and strong biofilm formation ability (P = 0.0026). Additionally, vancomycin, applied at sub minimal inhibitory concentrations, inhibited biofilm in four out of five strong biofilm-forming isolates. In conclusion, we suggest using agg and fsrB genes, together with the previously established gelE, for better prediction of biofilm strength and gelatinase activity, respectively. Future studies should explore the mechanism of biofilm inhibition by vancomycin and its possible use for antivirulence therapy. � 2017 The Author(s).EnglishOctober University for Modern Sciences and Artsجامعة أكتوبر للعلوم الحديثة والآدابUniversity of Modern Sciences and ArtsMSA Universityantiinfective agentvancomycinvirulence factorbacterial genebiofilmdrug effectEgyptEnterococcusgenetic association studygeneticsgenotypeGram positive infectiongrowth, development and aginghospitalhumanisolation and purificationmicrobiologyphysiologypolymerase chain reactionAnti-Bacterial AgentsBiofilmsEgyptEnterococcusGenes, BacterialGenetic Association StudiesGenotypeGram-Positive Bacterial InfectionsHospitalsHumansPolymerase Chain ReactionVancomycinVirulence FactorsArticlehttps://doi.org/10.1038/s41598-017-05901-0PubMed ID 28720810