Virginia Carvalhais1,2, Begoña Pérez-Cabezas1, Cátia Oliveira1, Rui Vitorino3,4, Manuel Vilanova1,5, Nuno Cerca2. 1. ICBAS - Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal. 2. CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. 3. iBiMED - Department of Medical Sciences, Institute for Biomedicine, University of Aveiro, Campus Universitário de Santiago, Agra do Crasto, 3810-193, Aveiro, Portugal. 4. Department of Physiology & Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal. 5. I3S - Instituto de Investigação e Inovação em Saúde & IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal.
Abstract
AIM: The goal of this study was to determine the effectiveness of antibiotics on Staphylococcus epidermidis biofilms with different proportions of dormant bacteria, using clinical and commensal isolates. MATERIALS & METHODS: The ability of S. epidermidis isolates to develop a dormant state was determined. The susceptibility of biofilms with prevented or induced dormancy to antibiotics was evaluated by enumeration of viable and cultivable cells, and confocal microscopy. RESULTS: Dormancy was observed in the majority of tested strains. Tetracycline and rifampicin enhanced the development of a viable but noncultivable biofilm state. CONCLUSION: Biofilms with induced dormancy were more likely to survive rifampicin. Furthermore, we found that the reduction of cultivable cells was not sufficient to reach definite conclusions on antimicrobial effectiveness.
AIM: The goal of this study was to determine the effectiveness of antibiotics on Staphylococcus epidermidis biofilms with different proportions of dormant bacteria, using clinical and commensal isolates. MATERIALS & METHODS: The ability of S. epidermidis isolates to develop a dormant state was determined. The susceptibility of biofilms with prevented or induced dormancy to antibiotics was evaluated by enumeration of viable and cultivable cells, and confocal microscopy. RESULTS: Dormancy was observed in the majority of tested strains. Tetracycline and rifampicin enhanced the development of a viable but noncultivable biofilm state. CONCLUSION: Biofilms with induced dormancy were more likely to survive rifampicin. Furthermore, we found that the reduction of cultivable cells was not sufficient to reach definite conclusions on antimicrobial effectiveness.
Authors: Gianmarco Mangiaterra; Elisa Carotti; Salvatore Vaiasicca; Nicholas Cedraro; Barbara Citterio; Anna La La Teana; Francesca Biavasco Journal: Int J Mol Sci Date: 2021-02-05 Impact factor: 5.923
Authors: Joana Castro; Ângela Lima; Lúcia G V Sousa; Aliona S Rosca; Christina A Muzny; Nuno Cerca Journal: Front Cell Infect Microbiol Date: 2022-01-05 Impact factor: 5.293