title: Inhibition of Staphylococcus aureus biofilm by Lactobacillus isolated from fine cocoa.
abstract: Biofilm production represents an important virulence and pathogenesis factor for Staphylococcus aureus. The formation of biofilms on medical devices is a major concern in hospital environments, as they can become a constant source of infection. Probiotic bacteria, such as Lactobacillus fermentum and L. plantarum, have been found to inhibit biofilm formation; however little is known about the underlying mechanism. In this study, we tested the activity of supernatants produced by L. fermentum TCUESC01 and L. plantarum TCUESC02, isolated during the fermentation of fine cocoa, against S. aureus CCMB262 biofilm production. We measured inhibition of biofilm formation in vitro and analyzed biofilm structure by confocal and electronic microscopy. Additionally, we quantified the expression of S. aureus genes icaA and icaR involved in the synthesis of the biofilm matrix by real-time PCR.
  
  
  
  Both Lactobacillus supernatants inhibited S. aureus growth. However, only L. fermentum TCUESC01 significantly reduced the thickness of the biofilm, from 14 μm to 2.83 μm (at 18 mg∙mL-1, 90 % of the minimum inhibitory concentration, MIC), 3.12 μm (at 14 mg∙mL-1, 70 % of the MIC), and 5.21 μm (at 10 mg∙mL-1, 50 % of the MIC). Additionally, L. fermentum TCUESC01 supernatant modulated the expression of icaA and icaR.
  
  
  
  L. fermentum TCUESC01 reduces the formation of S. aureus biofilm under subinhibitory conditions. Inhibition of biofilm production probably depends on modulation of the ica operon.
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil.
authors: Tauá Alves
authors: TA
authors: Melo
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil.
authors: Thalis Ferreira
authors: TF
authors: Dos Santos
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil.
authors: Milena Evangelista
authors: ME
authors: de Almeida
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil.
authors: Luiz Alberto Gusmão Fontes
authors: LA
authors: Junior
authors: Multidisciplinary Institute for Health, Federal University of Bahia, Rio de Contas Street, Candeiasn 17,58 Block, Vitória da Conquista, 45029-094, Bahia State, Brazil.
authors: Ewerton Ferraz
authors: EF
authors: Andrade
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil.
authors: Rachel Passos
authors: RP
authors: Rezende
authors: Multidisciplinary Institute for Health, Federal University of Bahia, Rio de Contas Street, Candeiasn 17,58 Block, Vitória da Conquista, 45029-094, Bahia State, Brazil.
authors: Lucas Miranda
authors: LM
authors: Marques
authors: Department of Biological Sciences, Santa Cruz State University, Ilhéus-Itabuna Road, km 16 Salobrinho, Ilhéus, 45662-900, Bahia State, Brazil. romanocc@uol.com.br.
authors: Carla Cristina
authors: CC
authors: Romano
mesh_terms: D000898:Antibiosis; D018441:Biofilms / Q000254:growth & development*; D000069956:Chocolate / Q000382:microbiology*; D003470:Culture Media; D005285:Fermentation; D007778:Lactobacillus / Q000302:isolation & purification / Q000502:physiology*; D052197:Limosilactobacillus fermentum / Q000502:physiology; D048191:Lactiplantibacillus plantarum / Q000502:physiology; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010641:Phenotype; D011137:Polystyrenes; D019936:Probiotics; D013211:Staphylococcus aureus / Q000502:physiology*
chemical_list: D003470:Culture Media; D011137:Polystyrenes
keywords: Antistaphylococcal; Biofilm; Lactobacillus fermentum; Probiotic properties; ica