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Campana R, Mangiaterra G, Tiboni M, Frangipani E, Biavasco F, Lucarini S, Citterio B. A Fluorinated Analogue of Marine Bisindole Alkaloid 2,2-Bis(6-bromo-1 H-indol-3-yl)ethanamine as Potential Anti-Biofilm Agent and Antibiotic Adjuvant Against Staphylococcus aureus. Pharmaceuticals (Basel) 2020; 13:ph13090210. [PMID: 32859056 PMCID: PMC7557854 DOI: 10.3390/ph13090210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/23/2022] Open
Abstract
Methicillin resistant Staphylococcus aureus (MRSA) infections represent a major global healthcare problem. Therapeutic options are often limited by the ability of MRSA strains to grow as biofilms on medical devices, where antibiotic persistence and resistance is positively selected, leading to recurrent and chronic implant-associated infections. One strategy to circumvent these problems is the co-administration of adjuvants, which may prolong the efficacy of antibiotic treatments, by broadening their spectrum and lowering the required dosage. The marine bisindole alkaloid 2,2-bis(6-bromo-1H-indol-3-yl)ethanamine (1) and its fluorinated analogue (2) were tested for their potential use as antibiotic adjuvants and antibiofilm agents against S. aureus CH 10850 (MRSA) and S. aureus ATCC 29213 (MSSA). Both compounds showed antimicrobial activity and bisindole 2 enabled 256-fold reduction (ΣFICs = 0.5) in the minimum inhibitory concentration (MIC) of oxacillin for the clinical MRSA strain. In addition, these molecules inhibited biofilm formation of S. aureus strains, and compound 2 showed greater eradicating activity on preformed biofilm compared to 1. None of the tested molecules exerted a viable but non-culturable cells (VBNC) inducing effect at their MIC values. Moreover, both compounds exhibited no hemolytic activity and a good stability in plasma, indicating a non-toxic profile, hence, in particular compound 2, a potential for in vivo applications to restore antibiotic treatment against MRSA infections.
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Affiliation(s)
- Raffaella Campana
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (R.C.); (M.T.); (E.F.)
| | - Gianmarco Mangiaterra
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (G.M.); (F.B.)
| | - Mattia Tiboni
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (R.C.); (M.T.); (E.F.)
| | - Emanuela Frangipani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (R.C.); (M.T.); (E.F.)
| | - Francesca Biavasco
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (G.M.); (F.B.)
| | - Simone Lucarini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (R.C.); (M.T.); (E.F.)
- Correspondence: (S.L.); (B.C.); Tel.: +39-0722-303-333 (S.L.); +39-0722-304-962 (B.C.)
| | - Barbara Citterio
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (R.C.); (M.T.); (E.F.)
- Correspondence: (S.L.); (B.C.); Tel.: +39-0722-303-333 (S.L.); +39-0722-304-962 (B.C.)
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Mangiaterra G, Cedraro N, Vaiasicca S, Citterio B, Galeazzi R, Laudadio E, Mobbili G, Minnelli C, Bizzaro D, Biavasco F. Role of Tobramycin in the Induction and Maintenance of Viable but Non-Culturable Pseudomonas aeruginosa in an In Vitro Biofilm Model. Antibiotics (Basel) 2020; 9:antibiotics9070399. [PMID: 32664334 PMCID: PMC7400124 DOI: 10.3390/antibiotics9070399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/12/2020] [Accepted: 07/08/2020] [Indexed: 01/25/2023] Open
Abstract
The recurrence of Pseudomonas aeruginosa (PA) biofilm infections is a major issue in cystic fibrosis (CF) patients. A pivotal role is played by the presence of antibiotic-unresponsive persisters and/or viable but non-culturable (VBNC) forms, whose development might be favored by subinhibitory antibiotic concentrations. The involvement of tobramycin and ciprofloxacin, widely used to treat CF PA lung infections, in the abundance of VBNC cells was investigated in PA biofilms models. In vitro biofilms of the laboratory strain PAO1-N and the clinical strain C24 were developed and starved by subculture for 170 days in a non-nutrient (NN) broth, unsupplemented or supplemented with one-quarter minimal inhibitory concentration (MIC) of tobramycin or ciprofloxacin. VBNC cells abundance, estimated as the difference between total live (detected by qPCR and flow cytometry) and colony forming unit (CFU) counts, showed a strain- and drug-specific pattern. A greater and earlier abundance of VBNC PAO1-N cells was detected in all conditions. Exposure of the C24 strain to NN and NN + ciprofloxacin induced only a transient VBNC subpopulation, which was more abundant and stable until the end of the experiment in tobramycin-exposed biofilms. The same response to tobramycin was observed in the PAO1-N strain. These findings suggest that low tobramycin concentrations might contribute to PA infection recurrence by favoring the development of VBNC forms.
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Affiliation(s)
- Gianmarco Mangiaterra
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
- Correspondence: ; Tel.: +39-071-220-4622; Fax: +39-071-220-4316
| | - Nicholas Cedraro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Salvatore Vaiasicca
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Barbara Citterio
- Department of Biomolecular Science, Biotechnology Section, University of Urbino “Carlo Bo”, via Arco d’Augusto 2, 61032 Fano, Italy;
| | - Roberta Galeazzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Emiliano Laudadio
- Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy;
| | - Giovanna Mobbili
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Cristina Minnelli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Davide Bizzaro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
| | - Francesca Biavasco
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131 Ancona, Italy; (N.C.); (S.V.); (R.G.); (G.M.); (C.M.); (D.B.); (F.B.)
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