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Wang Z, De Soir S, Glorieux A, Merabishvili M, Knoop C, De Vos D, Pirnay JP, Van Bambeke F. Bacteriophages as potential antibiotic potentiators in cystic fibrosis: A new model to study the combination of antibiotics with a bacteriophage cocktail targeting dual species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. Int J Antimicrob Agents 2024; 64:107276. [PMID: 39009289 DOI: 10.1016/j.ijantimicag.2024.107276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 06/17/2024] [Accepted: 07/10/2024] [Indexed: 07/17/2024]
Abstract
OBJECTIVES Staphylococcus aureus and Pseudomonas aeruginosa co-infections in patients with cystic fibrosis (CF) are associated with disease severity. Their treatment is complicated by biofilm formation in the sticky mucus obstructing the airways. We investigated the activity of phages-antibiotics combinations using a dual species biofilm (P. aeruginosa/S. aureus) formed in artificial sputum medium. METHODS Biofilmswere incubated with broad-spectrum antibiotics (meropenem, ceftazidime, ciprofloxacin, tobramycin) combined with a cocktail of two (bacterio)phages (PSP3 and ISP) proven active via spot tests and double agar on P. aeruginosa PAO1 and S. aureus ATCC 25923. RESULTS At the highest tested concentrations (100 x MIC), antibiotics alone caused a 20-50% reduction in biomass and reduced S. aureus and P. aeruginosa CFU of 2.3 to 2.8 and 2.1 to 3.6 log10, respectively. Phages alone reduced biofilm biomass by 23% and reduced P. aeruginosa CFU of 2.1 log10, but did not affect S. aureus viability. Phages enhanced antibiotic effects on biomass and exhibited additive effects with antibiotics against P. aeruginosa, but not against S. aureus. Following inhibition of bacterial respiration by phages in planktonic cultures rationalised these observations by demonstrating that PSP3 was effective at multiplicities of infection (MOI) as low as 10-4 plaque forming units (PFU)/CFU on P. aeruginosa, but ISP, at higher MOI (> 0.1) against S. aureus. CONCLUSION Pre-screening inhibition of bacterial respiration by phages may assist in selecting those showing activity at sufficiently low titers to showcase anti-biofilm activity in this complex but clinically-relevant in vitro model of biofilm.
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Affiliation(s)
- Zhifen Wang
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Steven De Soir
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Neder-over-Heembeek, Belgium
| | - Antoine Glorieux
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Neder-over-Heembeek, Belgium
| | - Maya Merabishvili
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Neder-over-Heembeek, Belgium
| | - Christiane Knoop
- Erasme Hospital, Université libre de Bruxelles, Brussels, Belgium
| | - Daniel De Vos
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Neder-over-Heembeek, Belgium
| | - Jean-Paul Pirnay
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Neder-over-Heembeek, Belgium
| | - Françoise Van Bambeke
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium.
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2
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Power AD, Mok WWK. Agar and agarose used for Staphylococcus aureus biofilm cultivation impact fluoroquinolone tolerance. J Appl Microbiol 2024; 135:lxae191. [PMID: 39066496 DOI: 10.1093/jambio/lxae191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/10/2024] [Accepted: 07/25/2024] [Indexed: 07/28/2024]
Abstract
AIMS Staphylococcus aureus is an opportunistic pathogen whose treatment is further complicated by its ability to form biofilms. In this study, we examine the impact of growing S. aureus biofilms on different polymerizing surfaces, specifically agar and agarose, on the pathogen's tolerance to fluoroquinolones. METHODS AND RESULTS Biofilms of two methicillin-resistant strains of S. aureus were grown on agar or agarose in the presence of the same added nutrients, and their antibiotic susceptibility to two fluoroquinolones, moxifloxacin (MXF) and delafloxacin (DLX), were measured. We also compared the metabolism and extracellular polymeric substances (EPS) production of biofilms that were grown on agar and agarose. CONCLUSIONS Biofilms that were grown on agarose were consistently more susceptible to antibiotics than those grown on agar. We found that in biofilms that were grown on agar, extracellular protein composition was higher, and adding EPS to agarose-grown biofilms increased their tolerance to DLX to levels that were comparable to agar-grown biofilms.
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Affiliation(s)
- Angela D Power
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, United States
| | - Wendy W K Mok
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, United States
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3
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Sheykhsaran E, Abbasi A, Memar MY, Ghotaslou R, Baghi HB, Mazraeh FN, Laghousi D, Sadeghi J. The role of Staphylococcus aureus in cystic fibrosis pathogenesis and clinico-microbiological interactions. Diagn Microbiol Infect Dis 2024; 109:116294. [PMID: 38678689 DOI: 10.1016/j.diagmicrobio.2024.116294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/05/2024] [Accepted: 03/29/2024] [Indexed: 05/01/2024]
Abstract
Cystic fibrosis (CF) is a progressive and inherited disease that affects approximately 70000 individuals all over the world annually. A mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene serves as its defining feature. Bacterial infections have a significant impact on the occurrence and development of CF. In this manuscript, we discuss the role and virulence factors of Staphylococcus aureus as an important human pathogen with the ability to induce respiratory tract infections. Recent studies have reported S. aureus as the first isolated bacteria in CF patients. Methicillin-resistant Staphylococcus aureus (MRSA) pathogens are approximately resistant to all β-lactams. CF patients are colonized by MRSA expressing various virulence factors including toxins, and Staphylococcal Cassette Chromosome mec (SCCmec) types, and have the potential for biofilm formation. Therefore, variations in clinical outcomes will be manifested. SCCmec type II has been reported in CF patients more than in other SCCmec types from different countries. The small-colony variants (SCVs) as specific morphologic subtypes of S. aureus with slow growth and unusual properties can also contribute to persistent and difficult-to-treat infections in CF patients. The pathophysiology of SCVs is complicated and not fully understood. Patients with cystic fibrosis should be aware of the intrinsic risk factors for complex S. aureus infections, including recurring infections, physiological issues, or coinfection with P. aeruginosa.
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Affiliation(s)
- Elham Sheykhsaran
- Immunology Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amin Abbasi
- Department of Food Science and Technology, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Reza Ghotaslou
- Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Bannazadeh Baghi
- Immunology Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fariba Naeimi Mazraeh
- Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Delara Laghousi
- Social Determinants of Health Research Center, Health Management and Safety Promotion Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Javid Sadeghi
- Immunology Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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Lee HJ, Lee SH, Hong SK, Gil BI, Lee KA. In Vitro Biological Activities of Hesperidin-Related Compounds with Different Solubility. Antioxidants (Basel) 2024; 13:727. [PMID: 38929166 PMCID: PMC11200626 DOI: 10.3390/antiox13060727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/02/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
The biological activities of hesperidin-related compounds, such as hesperetin laurate (HTL), hesperetin (HT), hesperidin (HD), and hesperidin glucoside (HDG), were investigated in vitro. The compounds showed different hydrophobicities, and the octanol-water partition coefficient log P were 7.28 ± 0.06 for HTL, 2.59 ± 0.04 for HT, 2.13 ± 0.03 for HD, and -3.45 ± 0.06 for HDG, respectively. In the DPPH assay and β-carotene bleaching assay to determine antioxidant capacity, all compounds tested showed antioxidant activity in a concentration-dependent manner, although to varying degrees. HTL and HT showed similarly high activities compared to HD or HDG. HD and HDG did not show a significant difference despite the difference in solubility between the two. Cytotoxicity was high; in the order of hydrophobicity-HTL > HT > HD > HDL in keratinocyte HaCaT cells. All compounds tested showed reducing effects on cellular inflammatory mediators and cytokines induced by UV irradiation. However, HTL and HT effectively reduced nitric oxide (NO), tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6) levels compared to HD and HDG. The inhibitory effects of hesperidin-related compounds on skin-resident microorganisms were evaluated by measuring minimum inhibitory concentration (MIC). HTL showed the highest inhibitory effects against Staphylococcus aureus, Cutibacterium acnes, Candida albicans, and Malassezia furfur, followed by HT, while HD and HDF showed little effect. In conclusion, the hydrophobicity of hesperidin-related compounds was estimated to be important for biological activity in vitro, as was the presence or absence of the sugar moiety.
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Affiliation(s)
- Hyo-Jun Lee
- Graduate School of Biotechnology, College of Life Science, Kyunghee University, Yongin 17104, Republic of Korea
| | - Sun-Hyung Lee
- R&D Center, Youngjin Bio Co., Suwon 16614, Republic of Korea
| | - Sun-Ki Hong
- School of Law, Dongguk University, Seoul 04620, Republic of Korea
| | - Bog-Im Gil
- Department of Food and Nutrition, Anyang University, Anyang 14028, Republic of Korea
| | - Kyung-Ae Lee
- Department of Food and Nutrition, Anyang University, Anyang 14028, Republic of Korea
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Trognon J, Rima M, Lajoie B, Roques C, El Garah F. NaCl-induced modulation of species distribution in a mixed P. aeruginosa / S. aureus / B.cepacia biofilm. Biofilm 2023; 6:100153. [PMID: 37711514 PMCID: PMC10497989 DOI: 10.1016/j.bioflm.2023.100153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023] Open
Abstract
Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia are notorious pathogens known for their ability to form resilient biofilms, particularly within the lung environment of cystic fibrosis (CF) patients. The heightened concentration of NaCl, prevalent in the airway liquid of CF patients' lungs, has been identified as a factor that promotes the growth of osmotolerant bacteria like S. aureus and dampens host antibacterial defenses, thereby fostering favorable conditions for infections. In this study, we aimed to investigate how increased NaCl concentrations impact the development of multi-species biofilms in vitro, using both laboratory strains and clinical isolates of P. aeruginosa, S. aureus, and B. cepacia co-cultures. Employing a low-nutrient culture medium that fosters biofilm growth of the selected species, we quantified biofilm formation through a combination of adherent CFU counts, qPCR analysis, and confocal microscopy observations. Our findings reaffirmed the challenges faced by S. aureus in establishing growth within 1:1 mixed biofilms with P. aeruginosa when cultivated in a minimal medium. Intriguingly, at an elevated NaCl concentration of 145 mM, a symbiotic relationship emerged between S. aureus and P. aeruginosa, enabling their co-existence. Notably, this hyperosmotic environment also exerted an influence on the interplay of these two bacteria with B. cepacia. We demonstrated that elevated NaCl concentrations play a pivotal role in orchestrating the distribution of these three species within the biofilm matrix. Furthermore, our study unveiled the beneficial impact of NaCl on the biofilm growth of clinically relevant mucoid P. aeruginosa strains, as well as two strains of methicillin-sensitive and methicillin-resistant S. aureus. This underscores the crucial role of the microenvironment during the colonization and infection processes. The results suggest that hyperosmotic conditions could hold the key to unlocking a deeper understanding of the genesis and behavior of CF multi-species biofilms.
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Affiliation(s)
- Jeanne Trognon
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Maya Rima
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Barbora Lajoie
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Christine Roques
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service de Bactériologie Hygiène, Toulouse, France
| | - Fatima El Garah
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
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Alio I, Moll R, Hoffmann T, Mamat U, Schaible UE, Pappenfort K, Alawi M, Schie M, Thünauer R, Stamm J, Rohde H, Streit WR. Stenotrophomonas maltophilia affects the gene expression profiles of the major pathogens Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro multispecies biofilm model. Microbiol Spectr 2023; 11:e0085923. [PMID: 37819084 PMCID: PMC10714729 DOI: 10.1128/spectrum.00859-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/21/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE In the past, studies have focused on bacterial pathogenicity in mono-species infections, in part ignoring the clinical relevance of diseases caused by more than one pathogen (i.e., polymicrobial infections). However, it is now common knowledge that multiple bacteria species are often involved in the course of an infection. For treatment of such infections, it is absolutely important to understand the dynamics of species interactions at possible infection sites and the molecular mechanisms behind these interactions. Here, we studied the impact of Stenotrophomonas maltophilia on its commensals Pseudomonas aeruginosa and Staphylococcus aureus in multispecies biofilms. We analyzed the 3D structural architectures of dual- and triple-species biofilms, niche formation within the biofilms, and the interspecies interactions on a molecular level. RNAseq data identified key genes involved in multispecies biofilm formation and interaction as potential drug targets for the clinical combat of multispecies infection with these major pathogens.
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Affiliation(s)
- Ifey Alio
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Raphael Moll
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Tim Hoffmann
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Uwe Mamat
- Cellular Microbiology, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center,Leibniz Research Alliance Infection , Borstel Gemany, Borstel, Germany
| | - Ulrich E. Schaible
- Cellular Microbiology, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center,Leibniz Research Alliance Infection , Borstel Gemany, Borstel, Germany
| | - Kai Pappenfort
- Institute of Microbiology, Friedrich Schiller University of Jena, Jena, Germany
| | - Malik Alawi
- Bioinformatics Core, UKE Hamburg, Hamburg, Germany
| | - Marcel Schie
- LIV, Leibniz Institute of Experimental Virology, Hamburg, Germany
| | - Roland Thünauer
- LIV, Leibniz Institute of Experimental Virology, Hamburg, Germany
| | - Johanna Stamm
- Institute for Medical Microbiology, Virology and Hygiene, UKE, Eppendorf, Hamburg, Germany
| | - Holger Rohde
- Institute for Medical Microbiology, Virology and Hygiene, UKE, Eppendorf, Hamburg, Germany
| | - Wolfgang R. Streit
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
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Jean-Pierre V, Boudet A, Sorlin P, Menetrey Q, Chiron R, Lavigne JP, Marchandin H. Biofilm Formation by Staphylococcus aureus in the Specific Context of Cystic Fibrosis. Int J Mol Sci 2022; 24:ijms24010597. [PMID: 36614040 PMCID: PMC9820612 DOI: 10.3390/ijms24010597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/31/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen whose characteristics support its success in various clinical settings including Cystic Fibrosis (CF). In CF, S. aureus is indeed the most commonly identified opportunistic pathogen in children and the overall population. S. aureus colonization/infection, either by methicillin-susceptible or methicillin-resistant strains, will become chronic in about one third of CF patients. The persistence of S. aureus in CF patients' lungs, despite various eradication strategies, is favored by several traits in both host and pathogen. Among the latter, living in biofilm is a highly protective way to survive despite deleterious environmental conditions, and is a common characteristic shared by the main pathogens identified in CF. This is why CF has earned the status of a biofilm-associated disease for several years now. Biofilm formation by S. aureus, and the molecular mechanisms governing and regulating it, have been extensively studied but have received less attention in the specific context of CF lungs. Here, we review the current knowledge on S. aureus biofilm in this very context, i.e., the importance, study methods, molecular data published on mono- and multi-species biofilm and anti-biofilm strategies. This focus on studies including clinical isolates from CF patients shows that they are still under-represented in the literature compared with studies based on reference strains, and underlines the need for such studies. Indeed, CF clinical strains display specific characteristics that may not be extrapolated from results obtained on laboratory strains.
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Affiliation(s)
- Vincent Jean-Pierre
- HSM—HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 34093 Montpellier, France
| | - Agathe Boudet
- VBIC—Virulence Bactérienne et Infections Chroniques, Université de Montpellier, INSERM U1047, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30900 Nîmes, France
| | - Pauline Sorlin
- HSM—HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, 34093 Montpellier, France
| | - Quentin Menetrey
- INFINITE—Institute for Translational Research in Inflammation, Université de Lille, INSERM U1286, CHU Lille, 59000 Lille, France
| | - Raphaël Chiron
- HSM—HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Centre de Ressources et de Compétences de la Mucoviscidose, CHU Montpellier, 34295 Montpellier, France
| | - Jean-Philippe Lavigne
- VBIC—Virulence Bactérienne et Infections Chroniques, Université de Montpellier, INSERM U1047, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30900 Nîmes, France
| | - Hélène Marchandin
- HSM—HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 34093 Montpellier, France
- Correspondence:
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Models using native tracheobronchial mucus in the context of pulmonary drug delivery research: Composition, structure and barrier properties. Adv Drug Deliv Rev 2022; 183:114141. [PMID: 35149123 DOI: 10.1016/j.addr.2022.114141] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/29/2021] [Accepted: 02/04/2022] [Indexed: 01/15/2023]
Abstract
Mucus covers all wet epithelia and acts as a protective barrier. In the airways of the lungs, the viscoelastic mucus meshwork entraps and clears inhaled materials and efficiently removes them by mucociliary escalation. In addition to physical and chemical interaction mechanisms, the role of macromolecular glycoproteins (mucins) and antimicrobial constituents in innate immune defense are receiving increasing attention. Collectively, mucus displays a major barrier for inhaled aerosols, also including therapeutics. This review discusses the origin and composition of tracheobronchial mucus in relation to its (barrier) function, as well as some pathophysiological changes in the context of pulmonary diseases. Mucus models that contemplate key features such as elastic-dominant rheology, composition, filtering mechanisms and microbial interactions are critically reviewed in the context of health and disease considering different collection methods of native human pulmonary mucus. Finally, the prerequisites towards a standardization of mucus models in a regulatory context and their role in drug delivery research are addressed.
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Unravelling the molecular mechanisms underlying chronic respiratory diseases for the development of novel therapeutics via in vitro experimental models. Eur J Pharmacol 2022; 919:174821. [DOI: 10.1016/j.ejphar.2022.174821] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/01/2022] [Accepted: 02/09/2022] [Indexed: 12/11/2022]
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Pharmacodynamics of Moxifloxacin, Meropenem, Caspofungin and their Combinations Against In Vitro Polymicrobial Inter-kingdom Biofilms. Antimicrob Agents Chemother 2021; 66:e0214921. [PMID: 34930026 DOI: 10.1128/aac.02149-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms colonize medical devices and are often recalcitrant to antibiotics. Inter-kingdom biofilms, when at least a bacterium and a fungus are co-isolated, increase the likelihood of therapeutic failures. In this work, a three-species in vitro biofilm model including S. aureus, E. coli and C. albicans was used to study the activity of the antibiotics moxifloxacin and meropenem, the antifungal caspofungin, and combinations of them against inter-kingdom biofilms. The culturable cells and total biomass were evaluated to determine the pharmacodynamic parameters of the drug response for the incubation with the drugs alone. The synergic or antagonistic effects (increased/decreased effects) of the combination of drugs were analysed with the highest single agent method. Biofilms were imaged in confocal microscopy after live/dead staining. The drugs had limited activity when used alone against single-, dual- or three-species biofilms. When used in combination, additive effects were observed against single- or dual-species biofilms, and increased effects (synergy) against biomass of three-species biofilms. In addition, the two antibiotics showed different patterns, moxifloxacin being more active when targeting S. aureus and meropenem when targeting E. coli. All these observations were confirmed by confocal microscopy images. Our findings highlight the interest in combining caspofungin with antibiotics against inter-kingdom biofilms.
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Boudet A, Sorlin P, Pouget C, Chiron R, Lavigne JP, Dunyach-Remy C, Marchandin H. Biofilm Formation in Methicillin-Resistant Staphylococcus aureus Isolated in Cystic Fibrosis Patients Is Strain-Dependent and Differentially Influenced by Antibiotics. Front Microbiol 2021; 12:750489. [PMID: 34721354 PMCID: PMC8554194 DOI: 10.3389/fmicb.2021.750489] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/22/2021] [Indexed: 12/17/2022] Open
Abstract
Cystic fibrosis (CF) is a genetic disease with lung abnormalities making patients particularly predisposed to pulmonary infections. Staphylococcus aureus is the most frequently identified pathogen, and multidrug-resistant strains (MRSA, methicillin-resistant S. aureus) have been associated with more severe lung dysfunction leading to eradication recommendations. Diverse bacterial traits and adaptive skills, including biofilm formation, may, however, make antimicrobial therapy challenging. In this context, we compared the ability of a collection of genotyped MRSA isolates from CF patients to form biofilm with and without antibiotics (ceftaroline, ceftobiprole, linezolid, trimethoprim, and rifampicin). Our study used standardized approaches not previously applied to CF MRSA, the BioFilm Ring test® (BRT®), the Antibiofilmogram®, and the BioFlux™ 200 system which were adapted for use with the artificial sputum medium (ASM) mimicking conditions more relevant to the CF lung. We included 63 strains of 10 multilocus sequence types (STs) isolated from 35 CF patients, 16 of whom had chronic colonization. The BRT® showed that 27% of the strains isolated in 37% of the patients were strong biofilm producers. The Antibiofilmogram® performed on these strains showed that broad-spectrum cephalosporins had the lowest minimum biofilm inhibitory concentrations (bMIC) on a majority of strains. A focus on four chronically colonized patients with inclusion of successively isolated strains showed that ceftaroline, ceftobiprole, and/or linezolid bMICs may remain below the resistance thresholds over time. Studying the dynamics of biofilm formation by strains isolated 3years apart in one of these patients using BioFlux™ 200 showed that inhibition of biofilm formation was observed for up to 36h of exposure to bMIC and ceftaroline and ceftobiprole had a significantly greater effect than linezolid. This study has brought new insights into the behavior of CF MRSA which has been little studied for its ability to form biofilm. Biofilm formation is a common characteristic of prevalent MRSA clones in CF. Early biofilm formation was strain-dependent, even within a sample, and not only observed during chronic colonization. Ceftaroline and ceftobiprole showed a remarkable activity with a long-lasting inhibitory effect on biofilm formation and a conserved activity on certain strains adapted to the CF lung environment after years of colonization.
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Affiliation(s)
- Agathe Boudet
- VBIC, INSERM U1047, Université de Montpellier, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, Nîmes, France
| | - Pauline Sorlin
- HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Département de Microbiologie, CHU de Nîmes, Montpellier, France
| | | | - Raphaël Chiron
- HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Centre de Ressources et de Compétences de la Mucoviscidose, CHU de Montpellier, Montpellier, France
| | - Jean-Philippe Lavigne
- VBIC, INSERM U1047, Université de Montpellier, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, Nîmes, France
| | - Catherine Dunyach-Remy
- VBIC, INSERM U1047, Université de Montpellier, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, Nîmes, France
| | - Hélène Marchandin
- HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Département de Microbiologie, CHU de Nîmes, Montpellier, France
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Frisch S, Boese A, Huck B, Horstmann JC, Ho DK, Schwarzkopf K, Murgia X, Loretz B, de Souza Carvalho-Wodarz C, Lehr CM. A pulmonary mucus surrogate for investigating antibiotic permeation and activity against Pseudomonas aeruginosa biofilms. J Antimicrob Chemother 2021; 76:1472-1479. [PMID: 33712824 DOI: 10.1093/jac/dkab068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/15/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Pulmonary infections associated with Pseudomonas aeruginosa can be life-threatening for patients suffering from chronic lung diseases such as cystic fibrosis. In this scenario, the formation of biofilms embedded in a mucus layer can limit the permeation and the activity of anti-infectives. OBJECTIVES Native human pulmonary mucus can be isolated from endotracheal tubes, but this source is limited for large-scale testing. This study, therefore, aimed to evaluate a modified artificial sputum medium (ASMmod) with mucus-like viscoelastic properties as a surrogate for testing anti-infectives against P. aeruginosa biofilms. METHODS Bacterial growth in conventional broth cultures was compared with that in ASMmod, and PAO1-GFP biofilms were imaged by confocal microscopy. Transport kinetics of three antibiotics, tobramycin, colistin, and ciprofloxacin, through native mucus and ASMmod were studied, and their activity against PAO1 biofilms grown in different media was assessed by determination of metabolic activity and cfu. RESULTS PAO1(-GFP) cultured in human pulmonary mucus or ASMmod showed similarities in bacterial growth and biofilm morphology. A limited permeation of antibiotics through ASMmod was observed, indicating its strong barrier properties, which are comparable to those of native human mucus. Reduced susceptibility of PAO1 biofilms was observed in ASMmod compared with LB medium for tobramycin and colistin, but less for ciprofloxacin. CONCLUSIONS These findings underline the importance of mucus as a biological barrier to antibiotics. ASMmod appears to be a valuable surrogate for studying mucus permeation of anti-infectives and their efficacy against PAO1 biofilms.
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Affiliation(s)
- Sarah Frisch
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Annette Boese
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
| | - Benedikt Huck
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Justus C Horstmann
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Duy-Khiet Ho
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
| | - Konrad Schwarzkopf
- Department of Anaesthesia and Intensive Care, Klinikum Saarbrücken, Germany
| | - Xabier Murgia
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
| | - Brigitta Loretz
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
| | | | - Claus-Michael Lehr
- Helmholtz-Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Saarbrücken, Germany
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Ruiz-Sorribas A, Poilvache H, Kamarudin NHN, Braem A, Van Bambeke F. In vitro polymicrobial inter-kingdom three-species biofilm model: influence of hyphae on biofilm formation and bacterial physiology. BIOFOULING 2021; 37:481-493. [PMID: 34225500 DOI: 10.1080/08927014.2021.1919301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/08/2021] [Accepted: 04/13/2021] [Indexed: 06/13/2023]
Abstract
Biofilms are an important medical burden, notably for patients with orthopaedic device-related infections. When polymicrobial, these infections are more lethal and recalcitrant. Inter-kingdom biofilm infections are poorly understood and challenging to treat. Here, an in vitro three-species model including Staphylococcus aureus, Escherichia coli and Candida albicans was developed, to represent part of the diversity observed in orthopaedic infections or other clinical contexts. The importance of fungal hyphae for biofilm formation and virulence factor expression was explored. Two protocols were set up, allowing, or not, for hyphal formation. Culturable cells and biomass were characterised in both models, and biofilms were imaged in bright-field, confocal and electron microscopes. The expression of genes related to virulence, adhesion, exopolysaccharide synthesis and stress response was analysed in early-stage and mature biofilms. It was found that biofilms enriched in hyphae had larger biomass and showed higher expression levels of genes related to bacterial virulence or exopolysaccharides synthesis.
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Affiliation(s)
- Albert Ruiz-Sorribas
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Hervé Poilvache
- Laboratoire de neuro musculo squelettique, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium
- Orthopaedic Surgery Department, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Nur Hidayatul Nazirah Kamarudin
- Biomaterials and Tissue Engineering Research Group, Department of Materials Engineering, KU Leuven, Leuven, Belgium
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Annabel Braem
- Biomaterials and Tissue Engineering Research Group, Department of Materials Engineering, KU Leuven, Leuven, Belgium
| | - Françoise Van Bambeke
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
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14
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Mello TP, Lackner M, Branquinha MH, Santos ALS. Impact of biofilm formation and azoles' susceptibility in Scedosporium/Lomentospora species using an in vitro model that mimics the cystic fibrosis patients' airway environment. J Cyst Fibros 2020; 20:303-309. [PMID: 33334714 DOI: 10.1016/j.jcf.2020.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND Scedosporium species are the second most isolated filamentous fungi from cystic fibrosis (CF) patients; however, little is known about their virulence aspects in a CF environment. In this context, the current study aimed to evaluate the (i) antifungal susceptibility profiles, (ii) ability to form biofilm and (iii) impact of biofilm formation on the susceptibility to azoles in 21 clinical isolates of Scedosporium recovered from CF patients. METHODS Scedosporium apiospermum (n=6), S. aurantiacum (n=6), S. minutisporum (n=3) and Lomentospora prolificans (n=6) were firstly used to compare the antifungal susceptibility profile using a standard culture broth (RPMI-1640) and a mucin (M)-containing synthetic CF sputum medium (SCFM). The ability to form biofilms was investigated in polystyrene microtiter plates containing Sabouraud-dextrose (a classical medium), SCFM and SCFM+M. Mature biofilms were tested for their susceptibility to azoles by microdilution assay. RESULTS Our results showed that the minimum inhibitory concentrations (MICs) for planktonic conidia ranged from 0.25 to >16.0 mg/L for voriconazole and 1.0 to >16.0 mg/L for posaconazole. Overall, the MICs for azoles increased from 2- to 8-folds when the susceptibility tests were performed using SCFM+M compared to RPMI-1640. All fungi formed robust biofilms on polystyrene surface at 72 h, with a significant increase in the MICs (ranging from 128- to 1024-times) against both azoles compared to the planktonic cells. CONCLUSION These findings confirm the challenge of antifungal treatment of CF patients infected with Scedosporium/Lomentospora and also demonstrated a strong biofilm formation, with extensive increase in antifungal resistance, triggered underconditions mimicking the CF patient airway.
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Affiliation(s)
- Thaís P Mello
- Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Michaela Lackner
- Medical University of Innsbruck, Institute for Hygiene and Medical Microbiology, Schöpfstrasse 41, 6020 Innsbruck, Austria
| | - Marta H Branquinha
- Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - André L S Santos
- Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Programa de Pós-Graduação em Bioquímica (PPGBq), Instituto de Química (IQ), Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro, Brazil.
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15
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Antimicrobial Susceptibility Testing in Pseudomonas aeruginosa Biofilms: One Step Closer to a Standardized Method. Antibiotics (Basel) 2020; 9:antibiotics9120880. [PMID: 33316877 PMCID: PMC7763878 DOI: 10.3390/antibiotics9120880] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022] Open
Abstract
The ability of Pseudomonas aeruginosa to form biofilm during a long-term infection makes it difficult to treat patients correctly. The current clinical antimicrobial susceptibility testing methods are based on the study of planktonic strains. A standardized protocol to analyze the antimicrobial susceptibility in biofilms is necessary for routine laboratories. The aims of this study were to develop a simple biofilm model and to study the antimicrobial susceptibility of P. aeruginosa strains in biofilm growth. Different artificial sputum media, and aerobiosis and microaerobiosis conditions were analyzed using a microtiter plate method and P. aeruginosa PAO1 as reference strain. Planktonic and biofilm antimicrobial susceptibility to cefepime, imipenem, azithromycin, gentamicin, tobramycin, and ciprofloxacin were determined in clinical and non-clinical P. aeruginosa strains. The Synthetic Cystic Fibrosis Medium was proposed as a good medium. The biofilm greatly increased the resistance to tested antimicrobials, except for azithromycin. Cefepime and imipenem showed poor anti-biofilm effect while tobramycin, gentamicin, and ciprofloxacin showed good activity in some strains. Azithromycin showed a better activity in biofilm than in planktonic state when aerobic conditions were used. This study establishes useful information to test antimicrobial susceptibility in P. aeruginosa biofilms, and includes possible antimicrobial options to treat long-term infected patients.
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16
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Sörensen M, Khakimov B, Nurjadi D, Boutin S, Yi B, Dalpke AH, Eigenbrod T. Comparative evaluation of the effect of different growth media on in vitro sensitivity to azithromycin in multi-drug resistant Pseudomonas aeruginosa isolated from cystic fibrosis patients. Antimicrob Resist Infect Control 2020; 9:197. [PMID: 33298147 PMCID: PMC7724801 DOI: 10.1186/s13756-020-00859-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/20/2020] [Indexed: 12/26/2022] Open
Abstract
Long-term treatment with azithromycin is a therapeutic option in Cystic Fibrosis (CF) patients chronically infected with P. aeruginosa. It was recently shown that azithromycin has direct antimicrobial activity when P. aeruginosa isolates are tested in Roswell Park Memorial Institute medium supplemented with fetal calf serum (RPMI 1640/FCS) by broth microdilution. We now investigated whether (i) azithromycin might also be active against multidrug resistant (MDR) P. aeruginosa isolated from CF patients and (ii) how in vitro sensitivity assays perform in synthetic cystic fibrosis sputum medium (SCFM), a medium that mimics the particular CF airway environment. In 17 (59%) out of 29 MDR P. aeruginosa CF isolates MICs for azithromycin ranged between 0.25 and 8 μg/ml and 12 isolates (41%) showed a MIC ≥512 μg/ml when measured in RPMI/FCS. In contrast, MICs were ≥ 256 μg/ml for all P. aeruginosa MDR isolates when tested in either SCFM or in conventional cation-adjusted Mueller Hinton Broth. High MIC values observed in CF adapted medium SCFM for both PAO1 and MDR P. aeruginosa CF isolates, as opposed to findings in RPMI, argue against routine azithromycin MIC testing of CF isolates.
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Affiliation(s)
- Michael Sörensen
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany. .,Laboratory Enders and Partners, 70193, Stuttgart, Germany.
| | - Bakhodur Khakimov
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Dennis Nurjadi
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Sébastien Boutin
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Buqing Yi
- Institute of Medical Microbiology and Hygiene, Medical Faculty, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - Alexander H Dalpke
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany. .,Institute of Medical Microbiology and Hygiene, Medical Faculty, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
| | - Tatjana Eigenbrod
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany. .,SLK-Kliniken Heilbronn, 74080, Heilbronn, Germany.
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17
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Poilvache H, Ruiz-Sorribas A, Sakoulas G, Rodriguez-Villalobos H, Cornu O, Van Bambeke F. Synergistic Effects of Pulsed Lavage and Antimicrobial Therapy Against Staphylococcus aureus Biofilms in an in-vitro Model. Front Med (Lausanne) 2020; 7:527. [PMID: 33043028 PMCID: PMC7527469 DOI: 10.3389/fmed.2020.00527] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 07/27/2020] [Indexed: 12/23/2022] Open
Abstract
Background: Prosthetic joint infections (PJI) are difficult to treat complications of joint arthroplasty. Debridement with implant retention is a common treatment strategy and frequently involves the use of pulsed lavage (PL). However, PL effects on biofilms and antibiotic activity have been scarcely studied in-vitro. We report the effects of PL, vancomycin or flucloxacillin used independently or in combination against Staphylococcus aureus biofilms. Methods: Biofilms of 3 methicillin-susceptible (MSSA) and of 3 methicillin-resistant (MRSA) S. aureus were grown on Ti6Al4V coupons in TGN (TSB + 1%glucose + 2%NaCl). After 24 h, PL was applied to half of the samples (50 mL saline from 5 cm). Samples were either reincubated for 24 h in TGN or TGN + flucloxacillin or vancomycin. Analyses included CFUs counts, biomass assays or fluorescence microscopy. Results: PL transiently reduced bacterial counts by 3-4 Log10 CFU/coupon, but bacterial regrowth to baseline levels was seen after 24 h. At 20 mg/L, flucloxacillin reduced both the CFU counts (3 Log10 CFU/coupon) and biomass (-70%) in one MSSA only, while vancomycin had no effects against MRSA. PL combined with a 24 h reincubation with vancomycin or flucloxacillin at 20 mg/L was synergistic (-5 to 6.5 Log10 CFU/coupon; 81-100% biomass reduction). Fluorescence microscopy confirmed that PL removed most of the biofilm and that subsequent antibiotic treatment partially killed bacteria. Conclusions: While PL only transiently reduces the bacterial load and antibiotics at clinically relevant concentrations show no or limited activity on biofilms, their combination is synergistic against MRSA and MSSA biofilms. These results highlight the need for thorough PL before antibiotic administration in PJI.
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Affiliation(s)
- Hervé Poilvache
- Laboratoire de Neuro-Musculo-Squelettique, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.,Laboratoire de Pharmacologie Cellulaire et Moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium.,Orthopaedic Surgery Department, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Albert Ruiz-Sorribas
- Laboratoire de Pharmacologie Cellulaire et Moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - George Sakoulas
- School of Medicine, University of California, San Diego, San Diego, CA, United States
| | | | - Olivier Cornu
- Laboratoire de Neuro-Musculo-Squelettique, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.,Orthopaedic Surgery Department, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Françoise Van Bambeke
- Laboratoire de Pharmacologie Cellulaire et Moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
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Activity of Antibiotics against Pseudomonas aeruginosa in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture Medium. Antimicrob Agents Chemother 2020; 64:AAC.02204-19. [PMID: 32015047 DOI: 10.1128/aac.02204-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/24/2020] [Indexed: 12/28/2022] Open
Abstract
Pseudomonas aeruginosa is a major cause of respiratory biofilm-related infections in patients with cystic fibrosis. We developed an in vitro pharmacodynamic model to study the activity of antipseudomonal antibiotics against PAO1 biofilms grown in artificial sputum medium with agar [ASM(+)] versus that against biofilms grown in Trypticase soy broth supplemented with glucose and NaCl (TGN). We measured bacterial counts, metabolic activity (fluorescein diacetate [FDA] hydrolysis), and biomass (crystal violet absorbance). Biofilms grew slower in ASM(+) than in TGN but reached the same CFU counts and metabolic activity in both media and a slightly higher biomass after 48 h in ASM(+) than in TGN. The concentration-response curves of the antibiotics after 24 h of incubation with mature biofilms showed maximal effects ranging from a 3 (ciprofloxacin)- to a 1.5 (ceftazidime, meropenem)-log10-CFU decrease, with tobramycin and colistin showing intermediate values. These maximal reductions in the numbers of CFU were similar in both media for ciprofloxacin and β-lactams but lower in ASM(+) than in TGN for tobramycin and colistin; they were reached at concentrations lower than the human maximum concentration in plasma for ciprofloxacin and β-lactams only. The reductions in metabolic activity and in biomass were low in both media. Small-colony variants were selected by tobramycin in ASM(+) and by ciprofloxacin in both media. The model was then successfully applied to 4 isolates from patients with cystic fibrosis. These biofilms showed CFU counts similar to those of PAO1 biofilms in ASM(+) but a higher biomass than PAO1 biofilms in ASM(+) and moderate differences in their susceptibility to antibiotics from that of PAO1 biofilms grown in this medium. This model proved useful to establish the pharmacodynamic profile of drugs against P. aeruginosa biofilms in the context of cystic fibrosis.
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Horiuk YV, Kukhtyn MD, Stravskyy YS, Klymnyuk SI, Vergeles KM, Horiuk VV. Influence of staphylococcal Phage SAvB14 on biofilms, formed by Staphylococcus aureus variant bovis. REGULATORY MECHANISMS IN BIOSYSTEMS 2019. [DOI: 10.15421/021948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The use of bacteriophages for the treatment of chronic inflammatory processes has proved to be relevant, especially during isolation of antibiotic-resistant pathogens formed in biofilms. The article presents the results of research on the influence of Phage SAvB14 on young and mature biofilms formed by Staphylococcus aureus variant bovis. In the experiments we used cultures of S. aureus and a specific Phage SAvB14 isolated from the secretion of the mammary gland of cows suffering from chronic mastitis. In the study of the influence of bacteriophage on formed biofilms we determined the optical density of the dye solution that was washed from the biofilm photometrically on a spectrophotometer PE-5400UV (Ecroskhim, Russia) and the number of staphylococcal cells in the biofilm after the action of the bacteriophage on 24-hour and 72-hour biofilms by a ten-fold dilution on beef-extract agar. It was determined that under the influence of the bacteriophage on young 24-hour biofilms of S. aureus var. bovis, the optical density of the dye solution from biofilm increased within 4 hours up to 10% and the number of microbial cells increased by 1.8 times. After 32 hours of bacteriophage action, the optical density of the dye solution decreased on average by 34% compared to the initial density and the number of S. aureus cells in the biofilm decreased by 30 times. This indicates that microbial cells of young biofilms are not subject to complete lysis during the action of even this specific bacteriophage. Degradation of 77.5% of biofilm under the influence of the bacteriophage was observed on mature 72-hour biofilm within 32 hours at 37 °C. At the same time, viable cells of S. aureus were not isolated from the biofilm. This indicates the high lytic activity of the bacteriophage against mature biofilm bacteria and the possibility of its use in chronic staphylococcal infections caused by S. aureus var. bovis. Thus, the obtained data indicate that when mature 72-hour biofilms are exposed to the researched bacteriophage, their degradation is more intense compared with the young 24-hour biofilms, and the amount of destroyed biofilm was on average 2 times higher. This suggests that the use of specific staphylococcal Phage SAvB14 isolated by us for the destruction of biofilm, formed by S. aureus var. bovis, is promising.
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