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Higazy D, Pham AD, van Hasselt C, Høiby N, Jelsbak L, Moser C, Ciofu O. In vivo evolution of antimicrobial resistance in a biofilm model of Pseudomonas aeruginosa lung infection. THE ISME JOURNAL 2024; 18:wrae036. [PMID: 38478426 PMCID: PMC10980832 DOI: 10.1093/ismejo/wrae036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/10/2024] [Accepted: 02/29/2024] [Indexed: 04/01/2024]
Abstract
The evolution of antimicrobial resistance (AMR) in biofilms has been repeatedly studied by experimental evolution in vitro, but rarely in vivo. The complex microenvironment at the infection site imposes selective pressures on the bacterial biofilms, potentially influencing the development of AMR. We report here the development of AMR in an in vivo mouse model of Pseudomonas aeruginosa biofilm lung infection. The P. aeruginosa embedded in seaweed alginate beads underwent four successive lung infection passages with or without ciprofloxacin (CIP) exposure. The development of CIP resistance was assessed at each passage by population analysis of the bacterial populations recovered from the lungs of CIP-treated and control mice, with subsequent whole-genome sequencing of selected isolates. As inflammation plays a crucial role in shaping the microenvironment at the infection site, its impact was explored through the measurement of cytokine levels in the lung homogenate. A rapid development of AMR was observed starting from the second passage in the CIP-treated mice. Genetic analysis revealed mutations in nfxB, efflux pumps (mexZ), and two-component systems (parS) contribution to CIP resistance. The control group isolates exhibited mutations in the dipA gene, likely associated with biofilm dispersion. In the initial two passages, the CIP-treated group exhibited an elevated inflammatory response compared to the control group. This increase may potentially contribute to the release of mutagenic reactive oxygen species and the development of AMR. In conclusion, this study illustrates the complex relationship between infection, antibiotic treatment, and immune response.
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Affiliation(s)
- Doaa Higazy
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Microbiology, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Anh Duc Pham
- Division of Systems Pharmacology & Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Coen van Hasselt
- Division of Systems Pharmacology & Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Niels Høiby
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Lars Jelsbak
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Claus Moser
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Oana Ciofu
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
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2
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Plotniece A, Sobolev A, Supuran CT, Carta F, Björkling F, Franzyk H, Yli-Kauhaluoma J, Augustyns K, Cos P, De Vooght L, Govaerts M, Aizawa J, Tammela P, Žalubovskis R. Selected strategies to fight pathogenic bacteria. J Enzyme Inhib Med Chem 2023; 38:2155816. [PMID: 36629427 PMCID: PMC9848314 DOI: 10.1080/14756366.2022.2155816] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Natural products and analogues are a source of antibacterial drug discovery. Considering drug resistance levels emerging for antibiotics, identification of bacterial metalloenzymes and the synthesis of selective inhibitors are interesting for antibacterial agent development. Peptide nucleic acids are attractive antisense and antigene agents representing a novel strategy to target pathogens due to their unique mechanism of action. Antisense inhibition and development of antisense peptide nucleic acids is a new approach to antibacterial agents. Due to the increased resistance of biofilms to antibiotics, alternative therapeutic options are necessary. To develop antimicrobial strategies, optimised in vitro and in vivo models are needed. In vivo models to study biofilm-related respiratory infections, device-related infections: ventilator-associated pneumonia, tissue-related infections: chronic infection models based on alginate or agar beads, methods to battle biofilm-related infections are discussed. Drug delivery in case of antibacterials often is a serious issue therefore this review includes overview of drug delivery nanosystems.
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Affiliation(s)
- Aiva Plotniece
- Latvian Institute of Organic Synthesis, Riga, Latvia,Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Riga Stradiņš University, Riga, Latvia,CONTACT Aiva Plotniece Latvian Institute of Organic Synthesis, Riga, Latvia
| | | | - Claudiu T. Supuran
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Fabrizio Carta
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Italy
| | - Fredrik Björkling
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, Center for Peptide-Based Antibiotics, University of Copenhagen, Copenhagen East, Denmark
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, Center for Peptide-Based Antibiotics, University of Copenhagen, Copenhagen East, Denmark
| | - Jari Yli-Kauhaluoma
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, Drug Research Program, University of Helsinki, Helsinki, Finland
| | - Koen Augustyns
- Infla-Med, Centre of Excellence, University of Antwerp, Antwerp, Belgium,Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
| | - Paul Cos
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Linda De Vooght
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Matthias Govaerts
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Juliana Aizawa
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Päivi Tammela
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Drug Research Program, University of Helsinki, Helsinki, Finland
| | - Raivis Žalubovskis
- Latvian Institute of Organic Synthesis, Riga, Latvia,Faculty of Materials Science and Applied Chemistry, Institute of Technology of Organic Chemistry, Riga Technical University, Riga, Latvia
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Rodgers AM, Lindsay J, Monahan A, Dubois AV, Faniyi AA, Plant BJ, Mall MA, Ekkelenkamp MB, Elborn S, Ingram RJ. Biologically Relevant Murine Models of Chronic Pseudomonas aeruginosa Respiratory Infection. Pathogens 2023; 12:1053. [PMID: 37624013 PMCID: PMC10458525 DOI: 10.3390/pathogens12081053] [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: 06/03/2023] [Revised: 08/09/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen and the leading cause of infection in patients with cystic fibrosis (CF). The ability of P. aeruginosa to evade host responses and develop into chronic infection causes significant morbidity and mortality. Several mouse models have been developed to study chronic respiratory infections induced by P. aeruginosa, with the bead agar model being the most widely used. However, this model has several limitations, including the requirement for surgical procedures and high mortality rates. Herein, we describe novel and adapted biologically relevant models of chronic lung infection caused by P. aeruginosa. Three methods are described: a clinical isolate infection model, utilising isolates obtained from patients with CF; an incomplete antibiotic clearance model, leading to bacterial bounce-back; and the establishment of chronic infection; and an adapted water bottle chronic infection model. These models circumvent the requirement for a surgical procedure and, importantly, can be induced with clinical isolates of P. aeruginosa and in wild-type mice. We also demonstrate successful induction of chronic infection in the transgenic βENaC murine model of CF. We envisage that the models described will facilitate the investigations of host and microbial factors, and the efficacy of novel antimicrobials, during chronic P. aeruginosa respiratory infections.
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Affiliation(s)
- Aoife M. Rodgers
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Jaime Lindsay
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Avril Monahan
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Alice V. Dubois
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Aduragbemi A. Faniyi
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Barry J. Plant
- Cork Centre for Cystic Fibrosis (3CF), Cork University Hospital, University College Cork, T12 E8YV Cork, Ireland
- The HRB Funded Clinical Research Facility, University College Cork, T12 E8YV Cork, Ireland
| | - Marcus A. Mall
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité—University of Medicine Berlin, 10117 Berlin, Germany
- German Center for Lung Research (DZL), 10117 Berlin, Germany
- Berlin Institute of Health at Charité—University of Medicine Berlin, 10117 Berlin, Germany
| | - Miquel B. Ekkelenkamp
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Stuart Elborn
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
| | - Rebecca J. Ingram
- Wellcome-Wolfson Institute of Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, UK (S.E.)
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Verstraete L, Aizawa J, Govaerts M, De Vooght L, Lavigne R, Michiels J, Van den Bergh B, Cos P. In Vitro Persistence Level Reflects In Vivo Antibiotic Survival of Natural Pseudomonas aeruginosa Isolates in a Murine Lung Infection Model. Microbiol Spectr 2023; 11:e0497022. [PMID: 37140371 PMCID: PMC10269860 DOI: 10.1128/spectrum.04970-22] [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: 12/05/2022] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Clinicians are increasingly confronted with the limitations of antibiotics to clear bacterial infections in patients. It has long been assumed that only antibiotic resistance plays a pivotal role in this phenomenon. Indeed, the worldwide emergence of antibiotic resistance is considered one of the major health threats of the 21st century. However, the presence of persister cells also has a significant influence on treatment outcomes. These antibiotic-tolerant cells are present in every bacterial population and are the result of the phenotypic switching of normal, antibiotic-sensitive cells. Persister cells complicate current antibiotic therapies and contribute to the development of resistance. In the past, extensive research has been performed to investigate persistence in laboratory settings; however, antibiotic tolerance under conditions that mimic the clinical setting remain poorly understood. In this study, we optimized a mouse model for lung infections with the opportunistic pathogen Pseudomonas aeruginosa. In this model, mice are intratracheally infected with P. aeruginosa embedded in seaweed alginate beads and subsequently treated with tobramycin via nasal droplets. A diverse panel of 18 P. aeruginosa strains originating from environmental, human, and animal clinical sources was selected to assess survival in the animal model. Survival levels were positively correlated with the survival levels determined via time-kill assays, a common method to study persistence in the laboratory. We showed that survival levels are comparable and thus that the classical persister assays are indicative of antibiotic tolerance in a clinical setting. The optimized animal model also enables us to test potential antipersister therapies and study persistence in relevant settings. IMPORTANCE The importance of targeting persister cells in antibiotic therapies is becoming more evident, as these antibiotic-tolerant cells underlie relapsing infections and resistance development. Here, we studied persistence in a clinically relevant pathogen, Pseudomonas aeruginosa. It is one of the six ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, P. aeruginosa, and Enterobacter spp.), which are considered major health threats. P. aeruginosa is mostly known to cause chronic lung infections in cystic fibrosis patients. We mimicked these lung infections in a mouse model to study persistence under more clinical conditions. It was shown that the survival levels of natural P. aeruginosa isolates in this model are positively correlated with the survival levels measured in classical persistence assays in vitro. These results not only validate the use of our current techniques to study persistence but also open opportunities to study new persistence mechanisms or evaluate new antipersister strategies in vivo.
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Affiliation(s)
- Laure Verstraete
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium
| | - Juliana Aizawa
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Matthias Govaerts
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Linda De Vooght
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium
| | - Bram Van den Bergh
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
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5
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Reyne N, McCarron A, Cmielewski P, Parsons D, Donnelley M. To bead or not to bead: A review of Pseudomonas aeruginosa lung infection models for cystic fibrosis. Front Physiol 2023; 14:1104856. [PMID: 36824474 PMCID: PMC9942929 DOI: 10.3389/fphys.2023.1104856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Abstract
Cystic fibrosis (CF) lung disease is characterised by recurring bacterial infections resulting in inflammation, lung damage and ultimately respiratory failure. Pseudomonas aeruginosa is considered one of the most important lung pathogens in those with cystic fibrosis. While multiple cystic fibrosis animal models have been developed, many fail to mirror the cystic fibrosis lung disease of humans, including the colonisation by opportunistic environmental pathogens. Delivering bacteria to the lungs of animals in different forms is a way to model cystic fibrosis bacterial lung infections and disease. This review presents an overview of previous models, and factors to consider when generating a new P. aeruginosa lung infection model. The future development and application of lung infection models that more accurately reflect human cystic fibrosis lung disease has the potential to assist in understanding the pathophysiology of cystic fibrosis lung disease and for developing treatments.
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Affiliation(s)
- Nicole Reyne
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia,Respiratory and Sleep Medicine, Women’s and Children’s Hospital, North Adelaide, SA, Australia,*Correspondence: Nicole Reyne,
| | - Alexandra McCarron
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia,Respiratory and Sleep Medicine, Women’s and Children’s Hospital, North Adelaide, SA, Australia
| | - Patricia Cmielewski
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia,Respiratory and Sleep Medicine, Women’s and Children’s Hospital, North Adelaide, SA, Australia
| | - David Parsons
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia,Respiratory and Sleep Medicine, Women’s and Children’s Hospital, North Adelaide, SA, Australia
| | - Martin Donnelley
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia,Respiratory and Sleep Medicine, Women’s and Children’s Hospital, North Adelaide, SA, Australia
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Laulund AS, Schwartz FA, Christophersen L, Kolpen M, Østrup Jensen P, Calum H, Høiby N, Thomsen K, Moser C. Hyperbaric oxygen therapy augments ciprofloxacin effect against Pseudomonas aeruginosa biofilm infected chronic wounds in a mouse model. Biofilm 2022; 5:100100. [PMID: 36660364 PMCID: PMC9843175 DOI: 10.1016/j.bioflm.2022.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/31/2022] Open
Abstract
Introduction Chronic wounds have a compromised microcirculation which leads to restricted gas exchange. The majority of these hypoxic wounds is infested with microorganisms congregating in biofilms which further hinders the antibiotic function. We speculate whether this process can be counteracted by hyperbaric oxygen therapy (HBOT). Methodology Twenty-eight BALB/c mice with third-degree burns were included in the analyses. Pseudomonas aeruginosa embedded in seaweed alginate beads was injected under the eschar to mimic a biofilm infected wound. Challenged mice were randomized to receive either 4 days with 1 x ciprofloxacin combined with 2 × 90 min HBOT at 2.8 standard atmosphere daily, 1 x ciprofloxacin as monotherapy or saline as placebo. The mice were clinically scored, and wound sizes were estimated by planimetry daily. Euthanasia was performed on day 8. Wounds were surgically removed in toto, homogenized and plated for quantitative bacteriology. Homogenate supernatants were used for cytokine analysis. Results P. aeruginosa was present in all wounds at euthanasia. A significant lower bacterial load was seen in the HBOT group compared to either the monotherapy ciprofloxacin group (p = 0.0008), or the placebo group (p < 0.0001). IL-1β level was significantly lower in the HBOT group compared to the placebo group (p = 0.0007). Both treatment groups had higher osteopontin levels than the placebo group (p = 0.002 and p = 0.004). The same pattern was seen in the S100A9 analysis (p = 0.01 and p = 0.008), whereas no differences were detected between the S100A8, the VEGF or the MMP8 levels in the three groups. Conclusion These findings show that HBOT improves the bactericidal activity of ciprofloxacin against P. aeruginosa wound biofilm in vivo. HBOT in addition to ciprofloxacin also modulates the host response to a less inflammatory phenotype.
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Affiliation(s)
- Anne Sofie Laulund
- Department of Clinical Microbiology, Copenhagen University, Rigshospitalet, Denmark,Corresponding author.
| | | | | | - Mette Kolpen
- Department of Clinical Microbiology, Copenhagen University, Rigshospitalet, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet and Department of Immunology and Microbiology (ISIM), University of Copenhagen, Denmark
| | - Henrik Calum
- Department of Clinical Microbiology, Hvidovre Hospital, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet and Department of Immunology and Microbiology (ISIM), University of Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Zealand University Hospital, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University, Rigshospitalet, Denmark
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Kašparová P, Vaňková E, Paldrychová M, Svobodová A, Hadravová R, Jarošová Kolouchová I, Masák J, Scholtz V. Non-thermal plasma causes Pseudomonas aeruginosa biofilm release to planktonic form and inhibits production of Las-B elastase, protease and pyocyanin. Front Cell Infect Microbiol 2022; 12:993029. [PMID: 36211963 PMCID: PMC9544392 DOI: 10.3389/fcimb.2022.993029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
The increasing risk of antibiotic failure in the treatment of Pseudomonas aeruginosa infections is largely related to the production of a wide range of virulence factors. The use of non-thermal plasma (NTP) is a promising alternative to antimicrobial treatment. Nevertheless, there is still a lack of knowledge about the effects of NTP on the virulence factors production. We evaluated the ability of four NTP-affected P. aeruginosa strains to re-form biofilm and produce Las-B elastase, proteases, lipases, haemolysins, gelatinase or pyocyanin. Highly strains-dependent inhibitory activity of NTP against extracellular virulence factors production was observed. Las-B elastase activity was reduced up to 82% after 15-min NTP treatment, protease activity and pyocyanin production by biofilm cells was completely inhibited after 60 min, in contrast to lipases and gelatinase production, which remained unchanged. However, for all strains tested, a notable reduction in biofilm re-development ability was depicted using spinning disc confocal microscopy. In addition, NTP exposure of mature biofilms caused disruption of biofilm cells and their dispersion into the environment, as shown by transmission electron microscopy. This appears to be a key step that could help overcome the high resistance of P. aeruginosa and its eventual elimination, for example in combination with antibiotics still highly effective against planktonic cells.
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Affiliation(s)
- Petra Kašparová
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
- Laboratory of Non-thermal Plasma, Department of Physics and Measurements, University of Chemistry and Technology in Prague, Prague, Czechia
- *Correspondence: Petra Kašparová,
| | - Eva Vaňková
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
- Laboratory of Non-thermal Plasma, Department of Physics and Measurements, University of Chemistry and Technology in Prague, Prague, Czechia
| | - Martina Paldrychová
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
- Laboratory of Non-thermal Plasma, Department of Physics and Measurements, University of Chemistry and Technology in Prague, Prague, Czechia
| | - Alžběta Svobodová
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
| | - Romana Hadravová
- Viral and Microbial Proteins, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Irena Jarošová Kolouchová
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
| | - Jan Masák
- Laboratory of Applied Biology, Department of Biotechnology, University of Chemistry and Technology in Prague, Prague, Czechia
| | - Vladimir Scholtz
- Laboratory of Non-thermal Plasma, Department of Physics and Measurements, University of Chemistry and Technology in Prague, Prague, Czechia
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8
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Schwartz FA, Christophersen L, Thomsen K, Baekdal S, Pals Bendixen M, Jørgensen M, Bull Rasmussen IK, Laulund AS, Høiby N, Moser C. Chicken IgY reduces the risk of Pseudomonas aeruginosa urinary tract infections in a murine model. Front Microbiol 2022; 13:988386. [PMID: 36160201 PMCID: PMC9505517 DOI: 10.3389/fmicb.2022.988386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
IntroductionUrinary tract infections (UTIs) with Pseudomonas aeruginosa are a severe problem in disposed patients in modern healthcare. Pseudomonas aeruginosa establishes recalcitrant biofilm infections and can develop antibiotic resistance. Gargling with avian egg yolk anti-Pseudomonas antibodies (IgY) has shown clinical effect in preventing onset of chronic P. aeruginosa lung infections in patients with cystic fibrosis (CF). Therefore, we speculated whether passive intravesically administered IgY immunotherapy could be a novel strategy against P. aeruginosa UTIs.AimTo evaluate if prophylactic repurposing of anti-Pseudomonas IgY can prevent UTIs with P. aeruginosa in a UTI mouse model.Materials and methodsIn vitro, P. aeruginosa (PAO1 and PAO3) was mixed with increasing concentrations of specific anti-Pseudomonas IgY (sIgY) or non-specific control IgY (cIgY) and/or freshly isolated human neutrophils. Bacterial growth was evaluated by the optical density at 600 nm. In vivo, via a temporary transurethral catheter, 10-week-old female Balb/c mice were intravesically infected with 50 ml of a bacterial suspension and sIgY, cIgY, or isotonic NaCl. IgY and NaCl were either co-instilled with the bacteria, or instilled prophylactically, 30 min prior to infection. The animals were euthanized 20 h after infection. Vesical bacteriology was quantified, and cytokine expression in the bladder homogenate was measured by multiplex cytokine assay.ResultsIn vitro, sIgY concentrations above 2.5% reduced bacterial growth in a dose-dependent manner. In vivo, a UTI lasting for minimum 7 days was established by installing 5 × 106 colony-forming units (CFU) of P. aeruginosa PAO1. sIgY reduced vesical bacterial load if co-installed with P. aeruginosa PAO1. Prophylactic sIgY and cIgY reduced bacterial load when compared to isotonic NaCl. CXCL2 and G-CSF were both increased in infected bladders compared to non-infected controls which had non-detectable levels. Co-installation of sIgY and bacteria nearly completely inhibited the inflammatory response. However, the cytokine levels in the bladder did not change after prophylactic administration of sIgY or cIgY.ConclusionProphylactic sIgY significantly reduces the amount of bacteria in the bladder in a mouse model of P. aeruginosa cystitis and may serve as a novel non-antibiotic strategy in preventing P. aeruginosa UTIs.
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Affiliation(s)
- Franziska A. Schwartz
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Lars Christophersen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Sarah Baekdal
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Maria Pals Bendixen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Mette Jørgensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | | | - Anne Sofie Laulund
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, København, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, København, Denmark
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, København, Denmark
- *Correspondence: Claus Moser,
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9
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Calum H, Trøstrup H, Laulund AS, Thomsen K, Christophersen L, Høiby N, Moser C. Murine burn lesion model for studying acute and chronic wound infections. APMIS 2022; 130:477-490. [PMID: 35441434 DOI: 10.1111/apm.13228] [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: 03/05/2021] [Accepted: 04/13/2022] [Indexed: 02/05/2023]
Abstract
Acute wounds, such as thermal injury, and chronic wounds are challenging for patients and the healthcare system around the world. Thermal injury of considerable size induces immunosuppression, which renders the patient susceptible to wound infections, but also in other foci like the airways and urinary tract. Infected thermal lesions can progress to chronic wounds with biofilm making them more difficult to treat. While animal models have their limitations, murine wound models are still the best tool at the moment to identify strategies to overcome these challenges. Here, we present a murine burn model, which has been developed to study biofilm formation, the significance of wound healing, and for identifying novel treatment candidates. Investigating the effect of a thermal injury in mice, we observed that 48 h after introduction of the injury, the mice showed a reduction in polymorphonuclear neutrophil granulocytes (PMNs) and a reduced capacity for phagocytosis and oxidative burst. Regarding the chronic wound, Pseudomonas aeruginosa biofilm arrested wound healing and kept the wound in an inflammatory state, but suppressing PMN function by means of the PMN factor S100A8/A9, corresponding to observations in human venous leg ulcers. Monotherapy and dual treatment with S100A8/A9 and ciprofloxacin on P. aeruginosa biofilm-infected murine wounds have been investigated. In combination, S100A8/A9 and ciprofloxacin reduced the bacterial quantity, lowered the proinflammatory response, and increased anti-inflammatory cytokines after 4 days of treatment. When the treatment was prolonged, an additional prevention of resistance development was detected in all the dual-treated mice. In the present review, we provide data on using the murine model for research with the aim of better understanding pathophysiology of wounds and for identifying novel treatments for humans suffering from these lesions.
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Affiliation(s)
- Henrik Calum
- Department of Clinical Microbiology, Hvidovre Hospital, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hannah Trøstrup
- Department of Plastic Surgery and Burns Treatment, Copenhagen University Hospital, Copenhagen, Denmark
| | - Anne Sofie Laulund
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lars Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Immunology and Microbiology (ISIM), University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
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10
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Laulund ASB, Trøstrup H, Lerche CJ, Thomsen K, Christophersen L, Calum H, Høiby N, Moser C. Synergistic effect of immunomodulatory S100A8/A9 and ciprofloxacin against Pseudomonas aeruginosa biofilm in a murine chronic wound model. Pathog Dis 2021; 78:5497298. [PMID: 31116394 DOI: 10.1093/femspd/ftz027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022] Open
Abstract
The majority of chronic wounds are associated with bacterial biofilms recalcitrant to antibiotics and host responses. Immunomodulatory S100A8/A9 is suppressed in Pseudomonas aeruginosa biofilm infected wounds. We aimed at investigating a possible additive effect between S100A8/A9 and ciprofloxacin against biofilms. MATERIALS/METHODS Thirty-two mice were injected with alginate-embedded P. aeruginosa following a third-degree burn. The mice were randomized into four groups receiving combination ciprofloxacin and S100A8/A9 or monotherapy ciprofloxacin, S100A8/A9 or a placebo and evaluated by host responses and quantitative bacteriology in wounds. In addition, in vitro checkerboard analysis was performed, with P. aeruginosa and ascending S100A8/A9 and ciprofloxacin concentrations. RESULTS S100A8/A9 augmented the effect of ciprofloxacin in vivo by lowering the bacterial quantity compared to the placebo arm and the two monointervention groups (P < 0.0001). S100A8 and 100A9 were increased in the double-treated group as compared to the monointervention groups (P = 0.032, P = 0.0023). Tissue inhibitor of metalloproteinases-1 and keratinocyte\chemokine chemoattractant-1 were increased in the double-intervention group compared to the S100A8/A9 group (P = 0.050, P = 0.050). No in vitro synergism was detected. CONCLUSION The observed ciprofloxacin-augmenting effect of S100A8/A9 in vivo was not confirmed by checkerboard analysis, indicating dependence on host cells for the S100A8/A9 effect. S100A8/A9 and ciprofloxacin is a promising therapy for optimizing chronic wound treatment.
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Affiliation(s)
- Anne Sofie Boe Laulund
- Department of Plastic Surgery, Zealand University Hospital, Sygehusvej 10, 4000 Roskilde, Denmark
| | - Hannah Trøstrup
- Department of Plastic Surgery, Zealand University Hospital, Sygehusvej 10, 4000 Roskilde, Denmark
| | - Christian Johann Lerche
- Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Kim Thomsen
- Department of Plastic Surgery, Zealand University Hospital, Sygehusvej 10, 4000 Roskilde, Denmark
| | - Lars Christophersen
- Department of Plastic Surgery, Zealand University Hospital, Sygehusvej 10, 4000 Roskilde, Denmark
| | - Henrik Calum
- Department of Clinical Microbiology, Amager and Hvidovre Hospital, Copenhagen University Hospital, Kettegaard Alle 30, 2650 Copenhagen, Denmark
| | - Niels Høiby
- Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Plastic Surgery, Zealand University Hospital, Sygehusvej 10, 4000 Roskilde, Denmark
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11
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Laulund AS, Schwartz F, Trøstrup H, Thomsen K, Christophersen L, Calum H, Ciofu O, Høiby N, Moser C. Adjunctive S100A8/A9 Immunomodulation Hinders Ciprofloxacin Resistance in Pseudomonas aeruginosa in a Murine Biofilm Wound Model. Front Cell Infect Microbiol 2021; 11:652012. [PMID: 33912476 PMCID: PMC8072475 DOI: 10.3389/fcimb.2021.652012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/19/2021] [Indexed: 12/24/2022] Open
Abstract
Objective Pseudomonas aeruginosa is known to contribute to the pathogenesis of chronic wounds by biofilm-establishment with increased tolerance to host response and antibiotics. The neutrophil-factor S100A8/A9 has a promising adjuvant effect when combined with ciprofloxacin, measured by quantitative bacteriology, and increased anti- and lowered pro-inflammatory proteins. We speculated whether a S100A8/A9 supplement could prevent ciprofloxacin resistance in infected wounds. Method Full-thickness 2.9cm2-necrosis was inflicted on 32 mice. On day 4, P.aeruginosa in seaweed alginate was injected sub-eschar to mimic a mono-pathogenic biofilm. Mice were randomized to receive ciprofloxacin and S100A8/A9 (n=14), ciprofloxacin (n=12) or saline (n=6). Half of the mice in each group were euthanized day 6 and the remaining day 10 post-infection. Mice were treated until sacrifice. Primary endpoint was the appearance of ciprofloxacin resistant P.aeruginosa. The study was further evaluated by genetic characterization of resistance, means of quantitative bacteriology, wound-size and cytokine-production. Results Three mice receiving ciprofloxacin monotherapy developed resistance after 14 days. None of the mice receiving combination therapy changed resistance pattern. Sequencing of fluoroquinolone-resistance determining regions in the ciprofloxacin resistant isolates identified two high-resistant strains mutated in gyrA C248T (MIC>32µg/ml) and a gyr B mutation was found in the sample with low level resistance (MIC=3µg/ml). Bacterial densities in wounds were lower in the dual treated group compared to the placebo group on both termination days. Conclusion This study supports the ciprofloxacin augmenting effect and indicates a protective effect in terms of hindered ciprofloxacin resistance of adjuvant S100A8/A9 in P.aeruginosa biofilm infected chronic wounds.
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Affiliation(s)
- Anne S Laulund
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Franziska Schwartz
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hannah Trøstrup
- Department of Plastic Surgery, Zealand University Hospital, Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lars Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Henrik Calum
- Department of Clinical Microbiology, Hvidovre Hospital, Hvidovre, Denmark
| | - Oana Ciofu
- Department of Immunology and Microbiology (ISIM), University of Copenhagen, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Immunology and Microbiology (ISIM), University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
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12
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Leenaars CH, Vries RBD, Reijmer J, Holthaus D, Visser D, Heming A, Elzinga J, Kempkes RW, Beumer W, Punt C, Meijboom FL, Ritskes-Hoitinga M. Animal models for cystic fibrosis: a systematic search and mapping review of the literature. Part 2: nongenetic models. Lab Anim 2021; 55:307-316. [PMID: 33557683 DOI: 10.1177/0023677221990688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Various animal models are available to study cystic fibrosis (CF). These models may help to enhance our understanding of the pathology and contribute to the development of new treatments. We systematically searched all publications on CF animal models. Because of the large number of models retrieved, we split this mapping review into two parts. Previously, we presented the genetic CF animal models. In this paper we present the nongenetic CF animal models. While genetic animal models may, in theory, be preferable for genetic diseases, the phenotype of a genetic model does not automatically resemble human disease. Depending on the research question, other animal models may thus be more informative.We searched Pubmed and Embase and identified 12,303 unique publications (after duplicate removal). All references were screened for inclusion by two independent reviewers. The genetic animal models for CF (from 636 publications) were previously described. The non-genetic CF models (from 189 publications) are described in this paper, grouped by model type: infection-based, pharmacological, administration of human materials, xenografts and other. As before for the genetic models, an overview of basic model characteristics and outcome measures is provided. This CF animal model overview can be the basis for an objective, evidence-based model choice for specific research questions. Besides, it can help to retrieve relevant background literature on outcome measures of interest.
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Affiliation(s)
- Cathalijn Hc Leenaars
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands.,Faculty of Veterinary Medicine, Department of Animals in Science and Society, Utrecht University, The Netherlands.,Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Rob Bm de Vries
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - Joey Reijmer
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - David Holthaus
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - Damian Visser
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - Anna Heming
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - Janneke Elzinga
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | - Rosalie Wm Kempkes
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands
| | | | - Carine Punt
- ProQR Therapeutics NV,Leiden, the Netherlands; Present position: BunyaVax BV, Lelystad, The Netherlands
| | - Franck Lb Meijboom
- Faculty of Veterinary Medicine, Department of Animals in Science and Society, Utrecht University, The Netherlands
| | - Merel Ritskes-Hoitinga
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, The Netherlands.,Department of Clinical Medicine, Aarhus University, Denmark
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13
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Brandenburg KS, Weaver AJ, Qian L, You T, Chen P, Karna SLR, Fourcaudot AB, Sebastian EA, Abercrombie JJ, Pineda U, Hong J, Wienandt NA, Leung KP. Development of Pseudomonas aeruginosa Biofilms in Partial-Thickness Burn Wounds Using a Sprague-Dawley Rat Model. J Burn Care Res 2020; 40:44-57. [PMID: 30137429 PMCID: PMC6300396 DOI: 10.1093/jbcr/iry043] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We used a modified Walker–Mason scald burn rat model to demonstrate that Pseudomonas aeruginosa, a common opportunistic pathogen in the burn ward and notable biofilm former, establishes biofilms within deep partial-thickness burn wounds in rats. Deep partial-thickness burn wounds, ~10% of the TBSA, were created in anesthetized male Sprague-Dawley rats (350–450 g; n = 84). Immediately post-burn, 100 µl of P. aeruginosa in phosphate-buffered saline at 1 × 103, 1 × 104, or 1 × 105 cells/wound was spread over the burn surface . At 1, 3, 7, and 11 days post-burn, animals were euthanized and blood and tissue were collected for complete blood counts, colony-forming unit (CFU) counts, biofilm gene expression, histology, scanning electron microscopy (SEM), and myeloperoxidase activity in the burn eschar. P. aeruginosa developed robust biofilm wound infections, plateauing at ~1 × 109 CFU/g burn tissue within 7 days regardless of inoculum size. Expression of Pseudomonas alginate genes and other virulence factors in the infected wound indicated formation of mature P. aeruginosa biofilm within the burn eschar. Compared to un-inoculated wounds, P. aeruginosa infection caused both local and systemic immune responses demonstrated by changes in systemic neutrophil counts, histology, and myeloperoxidase activity within the burn wound. Additionally, SEM showed P. aeruginosa enmeshed within an extracellular matrix on the burn surface as well as penetrating 500–600 µm deep into the eschar. P. aeruginosa establishes biofilms within deep partial-thickness burn wounds and invades deep into the burned tissue. This new in vivo biofilm infection model is valuable for testing novel anti-biofilm agents to advance burn care.
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Affiliation(s)
- Kenneth S Brandenburg
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Alan J Weaver
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Liwu Qian
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Tao You
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Ping Chen
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - S L Rajasekhar Karna
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Andrea B Fourcaudot
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Eliza A Sebastian
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Johnathan J Abercrombie
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Uzziel Pineda
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
| | - Jinson Hong
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas.,Armed Forces Busan Hospital, Republic of Korea Army
| | | | - Kai P Leung
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate (DCTRTRD), U.S. Army Institute of Surgical Research (USAISR), JBSA-Fort Sam Houston, San Antonio, Texas
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14
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In vivo demonstration of Pseudomonas aeruginosa biofilms as independent pharmacological microcompartments. J Cyst Fibros 2020; 19:996-1003. [PMID: 32067957 DOI: 10.1016/j.jcf.2020.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/24/2020] [Accepted: 01/25/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND Pseudomonas aeruginosa is difficult to eradicate from the lungs of cystic fibrosis (CF) patients due to biofilm formation. Organs and blood are independent pharmacokinetic (PK) compartments. Previously, we showed in vitro biofilms behave as independent compartments impacting the pharmacodynamics. The present study investigated this phenomenon in vivo. METHODS Seaweed alginate beads with P. aeruginosa resembling biofilms, either freshly produced (D0) or incubated for 5 days (D5) were installed s.c in BALB/c mice. Mice (n = 64) received tobramycin 40 mg/kg s.c. and were sacrificed at 0.5, 3, 6, 8, 16 or 24 h after treatment. Untreated controls (n = 14) were sacrificed, correspondingly. Tobramycin concentrations were determined in serum, muscle tissue, lung tissue and beads. Quantitative bacteriology was determined. RESULTS The tobramycin peak concentrations in serum was 58.3 (±9.2) mg/L, in lungs 7.1 mg/L (±2.3), muscle tissue 2.8 mg/L (±0.5) all after 0.5 h and in D0 beads 19.8 mg/L (±3.5) and in D5 beads 24.8 mg/L (±4.1) (both 3 h). A 1-log killing of P. aeruginosa in beads was obtained at 8h, after which the bacterial level remained stable at 16 h and even increased in D0 beads at 24 h. Using the established diffusion retardation model the free tobramycin concentration inside the beads showed a delayed buildup of 3 h but remained lower than the MIC throughout the 24 h. CONCLUSIONS The present in vivo study based on tobramycin exposure supports that biofilms behave as independent pharmacological microcompartments. The study indicates, reducing the biofilm matrix would increase free tobramycin concentrations and improve therapeutic effects.
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15
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Trøstrup H, Lerche CJ, Christophersen L, Jensen PØ, Høiby N, Moser C. Immune Modulating Topical S100A8/A9 Inhibits Growth of Pseudomonas aeruginosa and Mitigates Biofilm Infection in Chronic Wounds. Int J Mol Sci 2017; 18:ijms18071359. [PMID: 28672877 PMCID: PMC5535852 DOI: 10.3390/ijms18071359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/13/2017] [Accepted: 06/16/2017] [Indexed: 12/24/2022] Open
Abstract
Pseudomonas aeruginosa biofilm maintains and perturbs local host defense, hindering timely wound healing. Previously, we showed that P. aeruginosa suppressed S100A8/A9 of the murine innate host defense. We assessed the potential antimicrobial effect of S100A8/A9 on biofilm-infected wounds in a murine model and P. aeruginosa growth in vitro. Seventy-six mice, inflicted with a full-thickness burn wound were challenged subcutaneously (s.c.) by 106 colony-forming units (CFUs) of P. aeruginosa biofilm. Mice were subsequently randomized into two treatment groups, one group receiving recombinant murine S100A8/A9 and a group of vehicle controls (phosphate-buffered saline, PBS) all treated with s.c. injections daily for up to five days. Wounds were analyzed for quantitative bacteriology and contents of key inflammatory markers. Count of blood polymorphonuclear leukocytes was included. S100A8/A9-treatment ameliorated wound infection, as evaluated by quantitative bacteriology (p ≤ 0.05). In vitro, growth of P. aeruginosa was inhibited dose-dependently by S100A8/A9 in concentrations from 5 to 40 μg/mL, as determined by optical density-measurement (OD-measurement) and quantitative bacteriology. Treatment slightly augmented key inflammatory cytokine Tumor Necrosis Factor-α (TNF-α), but dampened interferon-γ (IFN-γ) levels and blood polymorphonuclear count. In conclusion, topical S100A8/A9 displays remarkable novel immune stimulatory and anti-infective properties in vivo and in vitro. Importantly, treatment by S100A8/A9 provides local infection control. Implications for a role as adjunctive treatment in healing of chronic biofilm-infected wounds are discussed.
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Affiliation(s)
- Hannah Trøstrup
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
| | - Christian Johann Lerche
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
| | - Lars Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
- Institute for Immunology and Microbiology, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
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16
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Karampatzakis A, Sankaran J, Kandaswamy K, Rice SA, Cohen Y, Wohland T. Measurement of oxygen concentrations in bacterial biofilms using transient state monitoring by single plane illumination microscopy. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa6db7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Pseudomonas aeruginosa Aggregate Formation in an Alginate Bead Model System Exhibits In Vivo-Like Characteristics. Appl Environ Microbiol 2017; 83:AEM.00113-17. [PMID: 28258141 PMCID: PMC5394317 DOI: 10.1128/aem.00113-17] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/23/2017] [Indexed: 11/20/2022] Open
Abstract
Alginate beads represent a simple and highly reproducible in vitro model system for diffusion-limited bacterial growth. In this study, alginate beads were inoculated with Pseudomonas aeruginosa and followed for up to 72 h. Confocal microscopy revealed that P. aeruginosa formed dense clusters similar in size to in vivo aggregates observed ex vivo in cystic fibrosis lungs and chronic wounds. Bacterial aggregates primarily grew in the bead periphery and decreased in size and abundance toward the center of the bead. Microsensor measurements showed that the O2 concentration decreased rapidly and reached anoxia ∼100 μm below the alginate bead surface. This gradient was relieved in beads supplemented with NO3− as an alternative electron acceptor allowing for deeper growth into the beads. A comparison of gene expression profiles between planktonic and alginate-encapsulated P. aeruginosa confirmed that the bacteria experienced hypoxic and anoxic growth conditions. Furthermore, alginate-encapsulated P. aeruginosa exhibited a lower respiration rate than the planktonic counterpart and showed a high tolerance toward antibiotics. The inoculation and growth of P. aeruginosa in alginate beads represent a simple and flexible in vivo-like biofilm model system, wherein bacterial growth exhibits central features of in vivo biofilms. This was observed by the formation of small cell aggregates in a secondary matrix with O2-limited growth, which was alleviated by the addition of NO3− as an alternative electron acceptor, and by reduced respiration rates, as well as an enhanced tolerance to antibiotic treatment. IMPORTANCEPseudomonas aeruginosa has been studied intensively for decades due to its involvement in chronic infections, such as cystic fibrosis and chronic wounds, where it forms biofilms. Much research has been dedicated to biofilm formation on surfaces; however, in chronic infections, most biofilms form small aggregates of cells not attached to a surface, but embedded in host material. In this study, bacteria were encapsulated in small alginate beads and formed aggregates similar to what is observed in chronic bacterial infections. Our findings show that aggregates are exposed to steep oxygen gradients, with zones of oxygen depletion, and that nitrate may serve as an alternative to oxygen, enabling growth in oxygen-depleted zones. This is important, as slow growth under low-oxygen conditions may render the bacteria tolerant toward antibiotics. This model provides an alternative to surface biofilm models and adds to the comprehension that biofilms do not depend on a surface for formation.
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18
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Moore JE, Mastoridis P. Clinical implications of Pseudomonas aeruginosa location in the lungs of patients with cystic fibrosis. J Clin Pharm Ther 2017; 42:259-267. [PMID: 28374433 DOI: 10.1111/jcpt.12521] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/05/2017] [Indexed: 12/18/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Pseudomonas aeruginosa is the leading cause of lung infection in patients with cystic fibrosis (CF) and is associated with significant morbidity and mortality. Antibiotics are regarded as the foundational pharmacological treatment for the suppressive management of chronic P. aeruginosa infections and to eradicate the first infection by P. aeruginosa. Inhalation remains a preferred route for drug administration, providing direct access to the site of infection while minimizing systemic side effects. Effective suppressive management of P. aeruginosa infections, however, requires an understanding of the location of the bacteria in the lungs and consideration of the factors that could limit access of the inhaled antibiotic to the infected area. This review provides a systematic assessment of the scientific literature to gain insight into the location of P. aeruginosa in the lungs of patients with CF and its clinical implications. The characteristics of antibiotic inhalation systems are also discussed in this context. METHODS We reviewed evidence-based literature from both human and animal studies in which P. aeruginosa lung location was reported. Relevant publications were identified through a screening strategy and summarized by reported P. aeruginosa location. RESULTS AND DISCUSSION Most areas of the conductive and respiratory zones of the lungs are susceptible to P. aeruginosa colonization. Deposition of an inhaled antibiotic is dependent on the device and formulation characteristics, as well as the ability of the patient to generate sufficient inhaled volume. As patients with CF often experience a decline in lung function, the challenge is to ensure that the inhaled antibiotic can be delivered throughout the bronchial tree. WHAT IS NEW AND CONCLUSION An effective drug delivery system that can target P. aeruginosa in both the respiratory and conductive zones is required. The chosen inhalation device should also offer a drug formulation that can be quickly and effectively delivered to specific lung locations, with minimal inspiratory effort from the patient.
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Affiliation(s)
- J E Moore
- Northern Ireland Public Health Laboratory, Department of Bacteriology, Belfast City Hospital, Belfast, UK
| | - P Mastoridis
- Respiratory Department, Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
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19
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Cao B, Christophersen L, Kolpen M, Jensen PØ, Sneppen K, Høiby N, Moser C, Sams T. Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model. PLoS One 2016; 11:e0153616. [PMID: 27100887 PMCID: PMC4839563 DOI: 10.1371/journal.pone.0153616] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/31/2016] [Indexed: 12/25/2022] Open
Abstract
Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100–1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm.
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Affiliation(s)
- Bao Cao
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Lars Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
- Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Kim Sneppen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
- Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Thomas Sams
- Biomedical Engineering, Dept. of Electrical Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
- * E-mail:
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Thomsen K, Trøstrup H, Christophersen L, Lundquist R, Høiby N, Moser C. The phagocytic fitness of leucopatches may impact the healing of chronic wounds. Clin Exp Immunol 2016; 184:368-77. [PMID: 26830371 DOI: 10.1111/cei.12773] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic non-healing wounds are significantly bothersome to patients and can result in severe complications. In addition, they are increasing in numbers, and a challenging problem to the health-care system. Handling of chronic, non-healing wounds can be discouraging due to lack of improvement, and a recent explanation can be the involvement of biofilm infections in the pathogenesis of non-healing wounds. Therefore, new treatment alternatives to improve outcome are continuously sought-after. Autologous leucopatches are such a new, adjunctive treatment option, showing promising clinical effects. However, the beneficial effect of the patches are not understood fully, although a major contribution is believed to be from the release of stimulating growth factors from activated thrombocytes within the leucopatch. Because the leucopatches also contain substantial numbers of leucocytes, the aim of the present study was to investigate the activity of the polymorphonuclear neutrophils (PMNs) within the leucopatch. By means of burst assay, phagocytosis assay, migration assay, biofilm killing assay and fluorescence in-situ hybridization (FISH) assay we showed significant respiratory burst in PMNs, active phagocytosis and killing of Pseudomonas aeruginosa by the leucopatch. In addition, bacterial-induced migration of PMNs from the leucopatch was shown, as well as uptake of P. aeruginosa by PMNs within the leucopatch. The present study substantiated that at least part of the beneficial clinical effect in chronic wounds by leucopatches is attributed to the activity of the PMNs in the leucopatch.
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Affiliation(s)
- K Thomsen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen
| | - H Trøstrup
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen
| | - L Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen
| | | | - N Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen
| | - C Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen
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Cao B, Christophersen L, Thomsen K, Sønderholm M, Bjarnsholt T, Jensen PØ, Høiby N, Moser C. Antibiotic penetration and bacterial killing in a Pseudomonas aeruginosa biofilm model. J Antimicrob Chemother 2015; 70:2057-63. [PMID: 25786481 DOI: 10.1093/jac/dkv058] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/12/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Treating biofilm infections successfully is a challenge. We hypothesized that biofilms may be considered as independent compartments with particular pharmacokinetics. We therefore studied the pharmacokinetics and pharmacodynamics of tobramycin in a seaweed alginate-embedded biofilm model. METHODS Seaweed alginate beads containing Pseudomonas aeruginosa were cultured in LB medium, sampled at day 1, 3, 5 or 7 and examined for the effect of treatment with tobramycin for 30 min. Treated beads were homogenized and the number of cfu was determined. The antibiotic concentration in the solution of homogenized beads was measured. Finally, beads were examined for live cells by Syto9 staining and for dead cells by propidium iodide staining using a confocal laser scanning microscope. RESULTS The antibiotic level in each bead was relatively stable (range 30-42 mg/L; MIC = 1.5 mg/L). There were fewer cfu in the tobramycin-treated beads than the non-treated beads (P < 0.016) and bacterial killing was reduced as the culture period increased from 1 to 7 days. Throughout the study period, increasing size and more superficial positioning of the microcolonies within the beads were demonstrated by confocal laser scanning microscopy. More dead cells (measured by propidium iodide staining) were observed in the treated group of beads, which supports the results obtained by culture. CONCLUSIONS The present study, simulating the clinical pharmacokinetics of tobramycin, demonstrates fast absorption of tobramycin in an in vitro biofilm model. In addition, this model system enables parallel investigation of pharmacokinetics and pharmacodynamics, providing a model for testing new treatment strategies.
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Affiliation(s)
- Bao Cao
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | | | - Kim Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Majken Sønderholm
- Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | | | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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Polymorphonuclear leukocytes restrict growth of Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. Infect Immun 2014; 82:4477-86. [PMID: 25114118 DOI: 10.1128/iai.01969-14] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cystic fibrosis (CF) patients have increased susceptibility to chronic lung infections by Pseudomonas aeruginosa, but the ecophysiology within the CF lung during infections is poorly understood. The aim of this study was to elucidate the in vivo growth physiology of P. aeruginosa within lungs of chronically infected CF patients. A novel, quantitative peptide nucleic acid (PNA) fluorescence in situ hybridization (PNA-FISH)-based method was used to estimate the in vivo growth rates of P. aeruginosa directly in lung tissue samples from CF patients and the growth rates of P. aeruginosa in infected lungs in a mouse model. The growth rate of P. aeruginosa within CF lungs did not correlate with the dimensions of bacterial aggregates but showed an inverse correlation to the concentration of polymorphonuclear leukocytes (PMNs) surrounding the bacteria. A growth-limiting effect on P. aeruginosa by PMNs was also observed in vitro, where this limitation was alleviated in the presence of the alternative electron acceptor nitrate. The finding that P. aeruginosa growth patterns correlate with the number of surrounding PMNs points to a bacteriostatic effect by PMNs via their strong O2 consumption, which slows the growth of P. aeruginosa in infected CF lungs. In support of this, the growth of P. aeruginosa was significantly higher in the respiratory airways than in the conducting airways of mice. These results indicate a complex host-pathogen interaction in chronic P. aeruginosa infection of the CF lung whereby PMNs slow the growth of the bacteria and render them less susceptible to antibiotic treatment while enabling them to persist by anaerobic respiration.
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Le S, He X, Tan Y, Huang G, Zhang L, Lux R, Shi W, Hu F. Mapping the tail fiber as the receptor binding protein responsible for differential host specificity of Pseudomonas aeruginosa bacteriophages PaP1 and JG004. PLoS One 2013; 8:e68562. [PMID: 23874674 PMCID: PMC3706319 DOI: 10.1371/journal.pone.0068562] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/29/2013] [Indexed: 12/21/2022] Open
Abstract
The first step in bacteriophage infection is recognition and binding to the host receptor, which is mediated by the phage receptor binding protein (RBP). Different RBPs can lead to differential host specificity. In many bacteriophages, such as Escherichia coli and Lactococcal phages, RBPs have been identified as the tail fiber or protruding baseplate proteins. However, the tail fiber-dependent host specificity in Pseudomonas aeruginosa phages has not been well studied. This study aimed to identify and investigate the binding specificity of the RBP of P. aeruginosa phages PaP1 and JG004. These two phages share high DNA sequence homology but exhibit different host specificities. A spontaneous mutant phage was isolated and exhibited broader host range compared with the parental phage JG004. Sequencing of its putative tail fiber and baseplate region indicated a single point mutation in ORF84 (a putative tail fiber gene), which resulted in the replacement of a positively charged lysine (K) by an uncharged asparagine (N). We further demonstrated that the replacement of the tail fiber gene (ORF69) of PaP1 with the corresponding gene from phage JG004 resulted in a recombinant phage that displayed altered host specificity. Our study revealed the tail fiber-dependent host specificity in P. aeruginosa phages and provided an effective tool for its alteration. These contributions may have potential value in phage therapy.
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Affiliation(s)
- Shuai Le
- Department of Microbiology, Third Military Medical University, Chongqing, China
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Xuesong He
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yinling Tan
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Guangtao Huang
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Lin Zhang
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Renate Lux
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Wenyuan Shi
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (FH); (WS)
| | - Fuquan Hu
- Department of Microbiology, Third Military Medical University, Chongqing, China
- * E-mail: (FH); (WS)
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