title: Gentamicin induces efaA expression and biofilm formation in Enterococcus faecalis.
abstract: Enterococci have been ranked among the leading causes of nosocomial bacteremia and urinary tract infection. This study aimed to investigate the effect of ampicillin, vancomycin, gentamicin and ceftizoxime on biofilm formation and gene expression of colonization factors on Enterococcus faecalis. Twelve clinical isolates of E. faecalis were used to investigate the effect of antibiotics on biofilm formation and gene expression of efaA, asa1, ebpA, esp and ace. Flow system assay and Microtiter plates were used for biofilm assay. Two hundred clinical isolates were used for confirming the effect of antibiotics on biofilm formation. Ampicillin, vancomycin and ceftizoxime did not have any significant effect on biofilm formation, but gentamicin induced biofilm formation in 89% of isolates. In twelve selected isolate gentamicin increased expression of esp (+50.9%) and efaA (+33.9%) genes and reduced or maintained expression of others (asa1:-47.4%, ebpA: 0, ace:-19.2%). Vancomycin increased expression of esp (+89.1%) but reduced the others (asa1: -34.9%, ebpA:-11%, ace:-30%, efaA:-60%). Ceftizoxime increased slightly ebpA (+19.7%) and reduced others (asa1:-66.2%, esp:-35%, ace:-28.1%, efaA:-38.4%). and ampicillin strongly increased expression of ace (+231%), esp (+131%) and ebpA (+83%) but reduced others (asa1:-85.5%, efaA:-47.4%). The findings of the present study showed that antibiotics may have a role in biofilm formation and sustainability of enterococci, especially in case of gentamicin. efaA gene may have an important role, especially in antibiotic induced biofilm formation by gentamicin. Experiments with efaA mutants are needed to investigate the exact effect of efaA on biofilm formation with antibiotic induced cells.
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Bacteriology, Faculty of Medical Sciences, Tehran, Iran.
authors.forename: Hossein Samadi
authors.initials: HS
authors.lastname: Kafil
authors.affiliation: Department of Bacteriology, Faculty of Medical Sciences, Tehran, Iran. Electronic address: mmmobarez@modares.ac.ir.
authors.forename: Ashraf Mohabati
authors.initials: AM
authors.lastname: Mobarez
authors.affiliation: Department of Biotechnology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mehdi Forouzandeh
authors.initials: MF
authors.lastname: Moghadam
authors.affiliation: Department of Biotechnology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra Sadat
authors.initials: ZS
authors.lastname: Hashemi
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yousefi
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms / Q000187:drug effects*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005839:Gentamicins / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005839:Gentamicins; C116503:efaA protein, Enterococcus faecalis
keywords: Antibiotic; Biofilm; Enterococcus faecalis; Expression; Gentamicin