ORCID Profile
0000-0001-7085-2864
Current Organisation
Phage Consulting Pty Ltd
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Pharmacology and Pharmaceutical Sciences | Pharmaceutical Sciences | Industrial Microbiology (incl. Biofeedstocks) |
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Expanding Knowledge in Technology
Publisher: Springer Science and Business Media LLC
Date: 09-07-2020
DOI: 10.1186/S12866-020-01891-8
Abstract: Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (phages) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I clinical trials, in treatment of multidrug-resistant (MDR) S. aureus infections. Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. At the end of the treatment period, there was a significant decrease (p 0.001) in bacterial load and wound size in infected phage- and vancomycin-treated groups compared with infected saline-treated mice. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No mortality was recorded associated with infections, and post-mortem examinations did not show any evident pathological lesions other than the skin wounds. No adverse effects related to the application of phages were observed. Topical application of phage cocktail AB-SA01 is effective, as shown by bacterial load reduction and wound closure, in the treatment of diabetic wound infections caused by MDR S. aureus . Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.
Publisher: American Medical Association (AMA)
Date: 08-2019
Publisher: MDPI AG
Date: 25-06-2014
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.IJPHARM.2018.04.063
Abstract: Microfluidics has recently emerged as a new method of manufacturing liposomes, which allows reproducible mixing in miliseconds on the nanoliter scale. Here we investigated the feasibility of a microfluidic flow focusing setup built from commercially available fittings to encapsulate phages into liposomes. Two types of Pseudomonas phages, PEV2 (Podovirus, ∼65 nm) and PEV40 (Myovirus, ∼220 nm), were used as model phages. A mixture of soy phosphatidylcholine and cholesterol at a ratio of 4:1 dissolved in absolute ethanol with a total solid content of 17.5 mg/mL was injected through the center inlet channel of a cross mixer. Phage suspensions were injected into the cross mixer from the two side channels intersecting with the center channel. The total flow rate (TFR) varied 160-320 µL/min and the organic/aqueous flow rate ratio (FRR) varied 1:3-2:3. The size of liposomes and the encapsulation efficiency both increased with increasing FRR and slightly decreased with increasing TFR. Due to the different size of the two studied phages, the size of liposomes encapsulating PEV2 were smaller (135-218 nm) than those encapsulating the Myovirus PEV40 (261-448 nm). Highest encapsulation efficiency of PEV2 (59%) and PEV40 (50%) was achieved at a TFR of 160 µL/ml and a FRR of 2:3. Generally, the encapsulation efficiency was slightly higher than that obtained from the conventional thin film hydration followed by extrusion method. In summary, the proposed microfluidic technique was capable of encapsulating phages of different size into liposomes with reasonable encapsulation efficiency and minimal titer reduction.
Publisher: Elsevier BV
Date: 08-2018
Publisher: American Society for Microbiology
Date: 20-08-2020
DOI: 10.1128/AAC.00993-20
Abstract: Concerns regarding increased prevalence of daptomycin (DAP)-resistant strains necessitate novel therapies for Enterococcus faecium infections. Obligately lytic bacteriophages are viruses that target, infect, and kill bacterial cells. Limited studies have evaluated phage-antibiotic combinations against E. faecium . After an initial screen of eight E. faecium strains, three strains with varying DAP hage susceptibilities were selected for further experiments.
Publisher: Elsevier BV
Date: 06-2019
Publisher: American Thoracic Society
Date: 11-2019
Publisher: BMJ
Date: 19-11-2012
Publisher: Springer Science and Business Media LLC
Date: 17-05-2019
DOI: 10.1007/S15010-019-01319-0
Abstract: We describe the use of bacteriophage therapy in a 26-year-old cystic fibrosis (CF) patient awaiting lung transplantation. The patient developed multidrug resistant (MDR) Pseudomonas aeruginosa pneumonia, persistent respiratory failure, and colistin-induced renal failure. We describe the use of intravenous bacteriophage therapy (BT) along with systemic antibiotics in this patient, lack of adverse events, and clinical resolution of infection with this approach. She did not have recurrence of pseudomonal pneumonia and CF exacerbation within 100 days following the end of BT and underwent successful bilateral lung transplantation 9 months later. Given the concern for MDR P. aeruginosa infections in CF patients, BT may offer a viable anti-infective adjunct to traditional antibiotic therapy.
Publisher: Microbiology Society
Date: 11-2011
Abstract: We describe the success of adjunctive bacteriophage therapy for refractory Pseudomonas aeruginosa urinary tract infection in the context of bilateral ureteric stents and bladder ulceration, after repeated failure of antibiotics alone. No bacteriophage-resistant bacteria arose, and the kinetics of bacteriophage and bacteria in urine suggest self-sustaining and self-limiting infection.
Publisher: American Society for Microbiology
Date: 17-06-2023
DOI: 10.1128/AAC.00461-20
Abstract: Comparative time-kill experiments with Staphylococcus aureus bacteriophage (phage) Sb-1 alone and phage-antibiotic combinations (PACs) against two methicillin-resistant S. aureus (MRSA) strains have shown synergy with both daptomycin-phage and vancomycin-phage combinations. PACs prevented development of phage resistance and demonstrated bactericidal activity for all triple combinations. In addition, the extracellular membrane vesicle (MV) formation and the potential impact of phage on MV suppression were examined.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 06-2017
Publisher: Springer Science and Business Media LLC
Date: 29-02-2016
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.CMI.2022.01.006
Abstract: Inhaled phage therapy has been revisited as a potential treatment option for respiratory infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa however, there is a distinct gap in understanding the dose-response effect. The aim of this study was to investigate the dose-response effect of Pseudomonas-targeting phage PEV31 delivered by pulmonary route in a mouse lung infection model. Neutropenic BALB/c mice were infected with MDR P. aeruginosa (2×10 At 24-h post-infection, all the phage-treated groups exhibited a significant reduction in pulmonary bacterial load by 1.3-1.9 log This study provides dose-response effect of inhaled phage therapy that may guide dose selection for treating P. aeruginosa respiratory infections in humans.
Publisher: American Society for Microbiology
Date: 02-2016
DOI: 10.1128/AAC.01426-15
Abstract: As antibiotic resistance increases, there is a need for new therapies to treat infection, particularly in cystic fibrosis (CF), where Pseudomonas aeruginosa is a ubiquitous pathogen associated with increased morbidity and mortality. Bacteriophages are an attractive alternative treatment, as they are specific to the target bacteria and have no documented side effects. The efficacy of phage cocktails was established in vitro . Two P. aeruginosa strains were taken forward into an acute murine infection model with bacteriophage administered either prophylactically, simultaneously, or postinfection. The infective burden and inflammation in bronchoalveolar lavage fluid (BALF) were assessed at various times. With low infective doses, both control mice and those undergoing simultaneous phage treatment cleared P. aeruginosa infection at 48 h, but there were fewer neutrophils in BALF of phage-treated mice (median, 73.2 × 10 4 /ml [range, 35.2 to 102.1 × 10 4 /ml] versus 174 × 10 4 /ml [112.1 to 266.8 × 10 4 /ml], P 0.01 for the clinical strain median, 122.1 × 10 4 /ml [105.4 to 187.4 × 10 4 /ml] versus 206 × 10 4 /ml [160.1 to 331.6 × 10 4 /ml], P 0.01 for PAO1). With higher infective doses of PAO1, all phage-treated mice cleared P. aeruginosa infection at 24 h, whereas infection persisted in all control mice (median, 1,305 CFU/ml [range, 190 to 4,700 CFU/ml], P 0.01). Bacteriophage also reduced CFU/ml in BALF when administered postinfection (24 h) and both CFU/ml and inflammatory cells in BALF when administered prophylactically. A reduction in soluble inflammatory cytokine levels in BALF was also demonstrated under different conditions. Bacteriophages are efficacious in reducing both the bacterial load and inflammation in a murine model of P. aeruginosa lung infection. This study provides proof of concept for future clinical trials in patients with CF.
Publisher: Elsevier BV
Date: 04-2019
Publisher: American Chemical Society (ACS)
Date: 18-11-2018
DOI: 10.1021/ACS.NANOLETT.8B03770
Abstract: Dielectric nanoantennas have recently emerged as promising elements for nonlinear and ultrafast nanophotonics due to their ability to concentrate light on the nanometer scale with low losses, while exhibiting large nonlinear susceptibilities. In this work, we demonstrate that single Si nanodisks covered with a thin 30 nm thick layer of Au can generate positive and negative sub-20 fs reflectivity modulations of ∼0.3% in the vicinity of the first-order anapole mode, when excited around the second-order anapole mode. The experimental results, characterized in the visible to near-infrared spectral range, suggest that the nonlinear optical Kerr effect is the responsible mechanism for the observed all-optical switching phenomena. These findings represent an important step toward nanoscale ultrafast all-optical signal processing.
Publisher: Wiley
Date: 13-01-2020
DOI: 10.1002/PHAR.2358
Abstract: Multidrug-resistant organisms have caused a marked depletion of effective antimicrobials, and the narrow pipeline of antibiotics has demanded the need to find novel therapeutic alternatives including nonantibiotic agents. Bacteriophages (phages) are viruses that use the bacterial machinery to infect, replicate, and kill bacterial cells. Although a marked decline in their use was driven by the discovery of antibiotics, the era of antibiotic resistance has led to a resurgence of phage therapy into clinical practice. The term phage-antibiotic synergy (PAS) was coined just over a decade ago and described that sublethal concentrations of antibiotics could stimulate phage production by bacterial cells. Recent literature has described PAS and other encouraging interactions with various phage and antibiotic combinations against a variety of bacterial strains. The primary objective of this review is to discuss the positive interactions between phage and antibiotic combinations, with an emphasis on PAS, reductions in bacterial growth or minimum inhibitory concentrations, enhanced biofilm eradication, and alterations in the emergence of bacterial resistance. A peer-reviewed literature search was conducted (1890-2019) using the PubMed, Medline, and Google Scholar databases. Although more investigation is certainly needed, the combination of bacteriophages with antibiotics is a promising strategy to target organisms with limited or no therapeutic options. This approach may also foster the ability to lower the antibiotic dose and may reduce the potential for antibiotic resistance emergence during therapy.
Publisher: SAGE Publications
Date: 2014
DOI: 10.2500/AJRA.2014.28.4001
Abstract: Staphylococcus aureus is the most common organism in recalcitrant chronic rhinosinusitis (CRS) and is often resistant to traditional antibiotic therapy. Bacteriophages (“phages”) are a potential candidate for a new, effective therapy. For phages to be useful in setting CRS, two minimum requirements must be presented: (1) phages must be effective against S. aureus biofilms and (2) phages must have a broad spectrum of activity. This study aimed to assess the in vitro activity of a phage cocktail (CockTail of Staphylococcus aureus specific bacteriophage [CT-SA]) against S. aureus biofilms and a broad panel of strains isolated from patients with CRS. The study examined 66 clinical isolates (CIs) of S. aureus. All isolates were tested for the susceptibility to phage lysis by spotting CT-SA onto bacterial lawns. To measure its effect on S. aureus biofilms, a minimum biofilm eradication concentration assay was used, using five S. aureus isolates. Biofilms of these isolates were grown, treated with CT-SA for 48 hours, fluorescently stained, and viewed using confocal scanning laser microscopy. CT-SA lysed 62 of 66 (94%) CIs of S. aureus. CT-SA treatment yielded significant reductions in biofilm mass for 4/5 CIs tested and for ATCC 25923. Challenge of S. aureus with a single phage resulted in the emergence of bacteriophage-insensitive mutants (BIM) with a frequency of 10 −7 , and challenge with CT-SA completely prevented their development. This study indicates that phage cocktail CT-SA can effectively eliminate S. aureus, in planktonic and biofilm forms, from the great majority of CIs from this hospital setting. In addition, its potential effect in preventing the emergence BIMs was a established. Thus, CT-SA has the potential to treat S. aureus infection and biofilm in CRS patients.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.IJPHARM.2018.11.026
Abstract: It was previously demonstrated that the loss of infectivity of a myovirus PEV44 after jet nebulization was closely related to a change in bacteriophage (phage) structure. In this follow-up study, we further examined the impact of jet nebulization on tailed phages, which constitute 96% of all known phages, from three different families, Podoviridae (PEV2), Myoviridae (PEV40) andSiphoviridae (D29). Transmission electron microscopy (TEM) identified major changes in phage structures after jet nebulization, correlating with their loss of infectivity. For the podovirus PEV2, jet nebulization had a negligible impact on its activity (0.04 log
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.EJPB.2022.05.014
Abstract: Bacteriophage (phage) therapy is a promising treatment strategy to combat antibiotic-resistant bacteria. Clinical reports from a century ago, as well as recent reports have revealed safety and efficacy of phage therapy for bacterial wound infections. However, the conventional liquid phage formulation and delivery platforms reported lack of dose control as it easily runs off from the infection site and it is impossible to determine total volume transfer. The aim of this study was to formulate phage liquids for topical delivery using a metered-dose spray. Two types of anti-Pseudomonas phages, PEV1 (myovirus) and PEV31 (podovirus) were formulated in 35% ethanol in water containing non-ionic polymers. The formulations were evaluated for physical properties, ease of spray, dripping upon spraying, drying time, in vitro release profiles, antibacterial activity, and storage stability. The optimized phage-polymer spray formulations were easily sprayable with minimal dripping and fast drying time. Phages were rapidly released from the formulation and inhibited the growth of Pseudomonas aeruginosa. Both PEV1 and PEV31 remained biologically stable in the optimized formulations during storage at 4 °C for eight weeks. This study showed the topical spray formulations containing non-ionic polymers in ethanol/water could be a promising and innovative therapeutic system for delivering phages.
Publisher: Elsevier BV
Date: 09-2019
Publisher: MDPI AG
Date: 29-01-2021
DOI: 10.3390/ANTIBIOTICS10020130
Abstract: Antibiotic resistance remains as an unresolved global challenge in the health care system, posing serious threats to global health. As an alternative to antibiotics, bacteriophage (phage) therapy is rising as a key to combating antibiotic-resistant bacterial infections. In order to deliver a phage to the site of infection, hydrogels have been formulated to incorporate phages, owing to its favorable characteristics in delivering biological molecules. This paper reviews the formulation of phage-delivering hydrogels for orthopedic implant-associated bone infection, catheter-associated urinary tract infection and trauma-associated wound infection, with a focus on the preparation methods, stability, efficacy and safety of hydrogels as phage carriers.
Publisher: Cold Spring Harbor Laboratory
Date: 05-05-2019
DOI: 10.1101/628339
Abstract: Multidrug resistant carbapenemase-producing Klebsiella pneumoniae capable of causing severe disease in humans is classified as an urgent threat by health agencies worldwide. Bacteriophages are being actively explored as potential therapeutics against these multidrug resistant pathogens. We are currently developing bacteriophage therapy against carbepenem-resistant K. pneumoniae belonging to the genetically erse, globally disseminated clonal group CG258. In an effort to define a robust experimental approach for effective selection of lytic viruses for therapy, we have fully characterized the bacterial genomes of 18 target strains, tested them against novel lytic bacteriophages, and generated phage-susceptibility profiles. The genomes of K. pneumoniae isolates carrying bla NDM and bla KPC were sequenced and isolates belonging to CG258 were selected for susceptibility testing using a panel of lytic bacteriophages (n=65). The local K. pneumoniae CG258 population was dominated by isolates belonging to sequence type ST258 clade 1 (86%). The primary differences between ST258 genomes were variations in the capsular locus ( cps ) and in prophage content. We showed that CG258-specific lytic phages primarily target the capsule, and that successful infection is blocked in many, post-adsorption, by immunity conferred by existing prophages. Five bacteriophages specifically active against K. pneumoniae ST258 clade 1 (n=5) belonging to the Caudovirales order were selected for further characterization. Our findings show that effective control of K. pneumoniae CG258 with phage will require mixes of erse lytic viruses targeting all relevant cps variants and allowing for variable prophage content. These insights will facilitate identification and selection of therapeutic phage candidates against this serious pathogen. Bacteriophages are natural agents that exclusively and selectively kill bacteria and have the potential to be useful in the treatment of multidrug resistant infections. K. pneumoniae CG258 is a main agent of life-threatening sepsis that is often resistant to last-line antibiotics. Our work highlights some key requirements for developing bacteriophage preparations targeting this pathogen. By defining the genomic profile of our clinical K. pneumoniae CG258 population and matching it with bacteriophage susceptibility patterns, we found that bacteriophage ability to lyse each strain correlates well with K. pneumoniae CG258 structural subtypes (capsule variants). This indicates that preparation of bacteriophage therapeutics targeting this pathogen should aim at including phages against each bacterial capsular subtype. This necessitates a detailed understanding of the ersity of circulating isolates in different geographical areas in order to make rational therapeutic choices.
Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.EJPB.2018.01.010
Abstract: Reduced infectivity of phage due to the nebulization process has been reported previously, but no visual evidence on structural change upon nebulization has been established, or whether these structural changes can be attributed to the titer reduction. In this study, transmission electron microscopy (TEM) was employed to assess the impact of three different types of nebulizers, air-jet, vibrating-mesh and static-mesh nebulizers, on the structural stability of a Myoviridae phage, PEV44, active against Pseudomonas aeruginosa. The morphology of the phage in the nebulized s les was categorized into two groups: "whole" (the capsid and tail held together) and "broken" (the capsid separated from the tail) phages. The "whole" phage group was further ided into three sub-groups: (1) intact, (2) contracted tail and (3) empty capsid. The starting stock suspension was found to contain considerable portions of "broken" phages (35.5 ± 6.7%), "whole" phages with contracted tails (9.9 ± 5.4%) and empty capsids (19.3 ± 8.9%). The fraction of "broken" phages was significantly increased after nebulization, with the air-jet nebulizer (83%) being more pronounced than the mesh type nebulizers (50-60%). While the amount of intact phages (2-10%) and whole phages with contracted tails (0-3%) were significantly decreased, the proportion of phages with empty capsids (15-36%) were not significantly different. Phages with broken features obtained by TEM quantification were 92.9 ± 3.2%, 74.8 ± 10.4% and 71.2 ± 11.0% for the jet, vibrating-mesh and static-mesh nebulizers, respectively. These results were found to be comparable with the titer loss obtained by the conventional plaque assay results. The in vitro aerosol performance and viable phage delivery of the three nebulizers was also assessed. The Omron nebulizer achieved a significantly higher viable respirable fraction (VRF) than the SideStream and Aeroneb Go (15.1 ± 5.8%, 2.4 ± 2.0%, 4.1 ± 2.7% respectively). In conclusion, this study identified various changes in the phage structure and viability of phage from different types of nebulizers. Understanding these effects and the phage tolerance to nebulization stresses can potentially improve our choice of the delivery method for inhaled phage therapy.
Publisher: MDPI AG
Date: 18-05-2020
DOI: 10.3390/V12050559
Abstract: The efficacy of phages in multispecies infections has been poorly examined. The in vitro lytic efficacies of phage cocktails AB-SA01, AB-PA01, which target Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and their combination against their hosts were evaluated in S. aureus and P. aeruginosa mixed-species planktonic and biofilm cultures. Green fluorescent protein (GFP)-labelled P. aeruginosa PAO1 and mCherry-labelled S. aureus KUB7 laboratory strains and clinical isolates were used as target bacteria. During real-time monitoring using fluorescence spectrophotometry, the density of mCherry S. aureus KUB7 and GFP P. aeruginosa PAO1 significantly decreased when treated by their respective phage cocktail, a mixture of phage cocktails, and gentamicin. The decrease in bacterial density measured by relative fluorescence strongly associated with the decline in bacterial cell counts. This microplate-based mixed-species culture treatment monitoring through spectrophotometry combine reproducibility, rapidity, and ease of management. It is amenable to high-throughput screening for phage cocktail efficacy evaluation. Each phage cocktail, the combination of the two phage cocktails, and tetracycline produced significant biofilm biomass reduction in mixed-species biofilms. This study result shows that these phage cocktails lyse their hosts in the presence of non-susceptible bacteria. These data support the use of phage cocktails therapy in infections with multiple bacterial species.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 04-2019
Publisher: Wiley
Date: 16-05-2021
DOI: 10.1111/ALL.14883
Abstract: Staphylococcus aureus is a pathogen of major concern in both acute infections and chronic conditions such as chronic rhinosinusitis (CRS). Bacteriophage (phage) therapy has recently regained interest for its potential to treat infections caused by antibiotic resistant strains including Methicillin Resistant Staphylococcus aureus (MRSA). However, bacteria can adapt and become resistant to phages. The aim of this study is to determine the potential for antibiotics to overcome phage resistance. The susceptibility of S. aureus clinical isolates (CIs) to phages J‐Sa36, Sa83 and Sa87 alone or in combination with protein synthesis inhibitor (PSI) antibiotics clindamycin, azithromycin and erythromycin was assessed using plaque spot assays, minimum inhibitory concentration (MIC) assays, double layer spot assays and resazurin assays. The safety and efficacy of subinhibitory PSI antibiotics in combination with phage was tested in a Sprague Dawley rat model of sinusitis infected with a phage resistant S. aureus CI. All three antibiotics at subinhibitory concentrations showed synergy when combined with all 3 phages against S. aureus CIs in planktonic and biofilm form and could sensitize phage‐resistant S. aureus to promote phage infection. The combination of topical subinhibitory clindamycin or azithromycin and phage was safe and could eradicate S . aureus sinonasal biofilms in vivo . Subinhibitory concentrations of PSI antibiotics could sensitize phage‐resistant S . aureus and MRSA strains to phages in vitro and in vivo . This data supports the potential use of phage‐PSI antibiotic combination therapies, in particular for difficult‐to‐treat infections with phage‐resistant S . aureus and MRSA strains.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Wiley
Date: 21-01-2014
DOI: 10.1002/ALR.21270
Abstract: Treatment of sinonasal bacterial biofilms continues to be a challenge in modern rhinology. This study's objective was to assess the safety and efficacy of topically applied Cocktail of S. aureus specific phage (CTSA) alone and in combination with ethylenediaminetetraacetic acid (EDTA) for treatment of Staphylococcus aureus biofilms in vivo. Using a sheep model of sinusitis, frontal sinuses (n = 6 per treatment) were flushed once daily with a CTSA (2 × 10(6) plaque forming units [PFU]/mL), with or without EDTA (0.075 mg/mL), and compared to a control flush containing saline and heat-inactivated CTSA. Safety was assessed using histology and scanning electron microscopy (SEM) after treatment for 3 days. Efficacy was assessed by quantifying the generation of S. aureus biofilms in the frontal sinuses after 5 days of treatment. Biofilm mass was compared between treatment groups and controls using LIVE/DEAD BacLight staining and confocal scanning laser microscopy to visualize the tissue sections. COMSTAT2 software was used to compute the biofilm mass present on tissue sections. Tissue morphology was conserved, with no significant signs of inflammation, when comparing control and test treatments. Furthermore, SEM analysis indicated test treatments were not toxic or damaging to mucosal cilia. COMSTAT2 quantification of biofilm showed a significant reduction in biofilm levels when comparing the control with CTSA (p = 0.0043), EDTA (p = 0.0095), and CTSA-EDTA (p = 0.0022) treatments. Results indicate that CTSA and EDTA are safe and efficacious for short-term topical application against S. aureus infection in a sheep sinusitis model, and have the potential to be translated to a clinical setting.
Publisher: MDPI AG
Date: 21-01-2019
DOI: 10.3390/V11010088
Abstract: Bacteriophages, viruses that only kill specific bacteria, are receiving substantial attention as nontraditional antibacterial agents that may help alleviate the growing antibiotic resistance problem in medicine. We describe the design and preclinical development of AB-SA01, a fixed-composition bacteriophage product intended to treat Staphylococcus aureus infections. AB-SA01 contains three naturally occurring, obligately lytic myoviruses related to Staphylococcus phage K. AB-SA01 component phages have been sequenced and contain no identifiable bacterial virulence or antibiotic resistance genes. In vitro, AB-SA01 killed 94.5% of 401 clinical Staphylococcus aureus isolates, including methicillin-resistant and vancomycin-intermediate ones for a total of 95% of the 205 known multidrug-resistant isolates. The spontaneous frequency of resistance to AB-SA01 was ≤3 × 10−9, and resistance emerging to one component phage could be complemented by the activity of another component phage. In both neutropenic and immunocompetent mouse models of acute pneumonia, AB-SA01 reduced lung S. aureus populations equivalently to vancomycin. Overall, the inherent characteristics of AB-SA01 component phages meet regulatory and generally accepted criteria for human use, and the preclinical data presented here have supported production under good manufacturing practices and phase 1 clinical studies with AB-SA01.
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.TRSL.2018.12.002
Abstract: Pseudomonas aeruginosa (PA) is a bacterial pathogen that frequently displays antibiotic resistance. Its presence within the sinuses of chronic rhinosinusitis sufferers is associated with poorer quality of life. Obligately lytic bacteriophages (phages) are viruses that infect, replicate within, and lyse bacteria, causing bacterial death. The aims of this study were to assess the safety and efficacy of a PA phage cocktail (CT-PA) in a sheep model of rhinosinusitis. The sheep rhinosinusitis model was adapted to simulate PA infection in sheep frontal sinuses. To assess efficacy, after a 7-day biofilm formation period, sheep received twice-daily frontal trephine flushes of CT-PA or saline for 1 week. Biofilm quantitation on frontal sinus mucosa was performed using LIVE/DEAD BacLight staining. To assess safety, sheep received twice-daily frontal trephine flushes of CT-PA or vehicle control for 3 weeks. Blood and fecal s les were collected throughout treatment. Histopathology of frontal sinus, lung, heart, liver, spleen, and kidney tissue was performed. Sinus cilia were visualized using scanning electron microscopy (SEM). The Efficacy arm showed a statistically significant reduction in biofilm biomass with all concentrations of CT-PA tested (P < 0.05). Phage presence in sinuses was maintained for at least 16hours after the final flush. All Safety arm sheep completed 3 weeks of treatment. Phage was detected consistently in feces and sporadically in blood and organ s les. Histology and SEM of tissues revealed no treatment-related damage. In conclusion, CT-PA was able to decrease sinus PA biofilm at concentrations of 10
Publisher: Wiley
Date: 14-12-2017
DOI: 10.1002/ALR.22046
Abstract: Bacteriophage (phage) therapy has been proposed as an alternative to antibiotics. Phages have been shown to kill antibiotic resistant Staphylococcus aureus strains however, it is unknown whether stress-induced antibiotic tolerance affects S. aureus susceptibility to phages. Our objective was to determine the effectiveness of 2 phages currently in clinical development, against antibiotic-resistant and induced antibiotic-tolerant clinical S. aureus isolates. Antibiotic tolerant S. aureus strains were induced by incubation with increasing concentrations of gentamicin, mupirocin, and ciprofloxacin over time and their susceptibility to 2 clinically relevant phages (Sa83 and Sa87) was assessed. In addition, phage susceptibility was tested in relation to the antibiotic sensitivity of 65 clinical S. aureus isolates, harvested from the sinonasal cavities of chronic rhinosinusitis (CRS) patients. Phage sensitivity was assessed using a plaque spot assay and by measuring optical density values to observe planktonic S. aureus growth in the presence of the phage. Alamar Blue assays were used to assess biofilm viability after phage treatment. Frequency of antibiotic resistance amongst clinical S. aureus isolates was 90.7% (59/65) with 13 of 65 (20.0%) identified as multidrug-resistant. Tolerance to gentamicin, mupirocin, and ciprofloxacin was rapidly induced by incubation with increasing concentrations of respective antibiotics. There was no significant difference in phage sensitivity between antibiotic-sensitive and resistant/tolerant S. aureus clinical isolates in planktonic and biofilm form. Clinical S. aureus isolates from CRS patients have a high (20%) incidence of multidrug resistance. Antibiotic resistance or tolerance did not affect phage susceptibility of those isolates.
Publisher: Research Square Platform LLC
Date: 08-04-2020
DOI: 10.21203/RS.3.RS-20603/V1
Abstract: Background: Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (“phages”) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I trials, in treatment of multidrug-resistant (MDR) S. aureus infections. Methods: Using a diabetic mouse model, bilateral six-millimetre excisional deep skin wounds inflicted on the dorsum of Balb/c mice were infected with 6.7 log 10 colony-forming units (CFU) of clinical MDR S. aureus . Infections were treated topically with AB-SA01, or controls: saline, or saline plus intraperitoneal (IP) vancomycin. Bacterial load and wound healing parameters were used to assess treatment efficacy. Results : Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No adverse effects related to the application of phages were observed. Conclusion: Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.
Publisher: Springer Science and Business Media LLC
Date: 04-04-2019
Publisher: MDPI AG
Date: 22-03-2021
DOI: 10.3390/MICROORGANISMS9030660
Abstract: Antibiotic treatment for Pseudomonas aeruginosa (Pa) in cystic fibrosis is limited in efficacy and may lead to multi-drug resistance (MDR). Alternatives such as bacteriophages are being explored but well designed, and controlled trials are crucial. The rational selection of patients with bacteriophage susceptible infections is required for both safety and efficacy monitoring. We questioned whether bacteriophage susceptibility profiles were constant or variable over time, variability having been reported with antibiotics. Serial Pa isolates (n = 102) from 24 chronically infected cystic fibrosis (CF) patients over one year were investigated with plaque and antibiotic disc diffusion assays. Variable number tandem repeat (VNTR) analysis identified those patients with isolate. A median (range) of 4 (3–6) isolates atient were studied. Twenty-one (87.5%) in iduals had a single VNTR type three (12.5%) had two VNTR types at different times. Seventy-five percent of isolates were sensitive to bacteriophage at ≥ 1 concentration 50% of isolates were antibiotic multidrug resistant. Serial isolates, even when representing a single VNTR type, varied in sensitivity to both bacteriophages and antibiotics. The rates of sensitivity to bacteriophage supports the development of this therapy however, the variability in response has implications for the selection of patients in future trials which must be on the basis of current, not past, isolate testing.
Publisher: Future Medicine Ltd
Date: 07-2012
DOI: 10.2217/FMB.12.58
Publisher: MDPI AG
Date: 16-03-2023
DOI: 10.3390/ANTIBIOTICS12030593
Abstract: Bacteriophages (phages) are antimicrobials with resurgent interest that are being investigated for the treatment of antibiotic refractory infection, including for Pseudomonas aeruginosa (Pa) lung infection in cystic fibrosis (CF). In vitro work supports the use of this therapy in planktonic and biofilm culture models however, consistent data are lacking for efficacy across different clinical Pa strains, culture models, and in combination with antibiotics in clinical use. We first examined the efficacy of a 4-phage cocktail as an adjunct to our CF centre’s first-line systemic combination antibiotic therapy (ceftazidime + tobramycin) for 16 different clinical Pa strains and then determined subinhibitory interactions for a subset of these strains with each antibiotic in planktonic and biofilm culture. When a 4-phage cocktail (4 × 108 PFU/mL) was added to a ceftazidime-tobramycin combination (ceftazidime 16 mg/mL + tobramycin 8 mg/mL), we observed a 1.7-fold and 1.3-fold reduction in biofilm biomass and cell viability, respectively. The four most antibiotic resistant strains in biofilm were very susceptible to phage treatment. When subinhibitory concentrations of antibiotics and phages were investigated, we observed additivity/synergy as well as antagonism/inhibition of effect that varied across the clinical strains and culture model. In general, more additivity was seen with the phage-ceftazidime combination than with phage-tobramycin, particularly in biofilm culture, where no instances of additivity were seen when phages were combined with tobramycin. The fact that different bacterial strains were susceptible to phage treatment when compared to standard antibiotics is promising and these results may be relevant to ongoing clinical trials exploring the use of phages, in particular in the selection of subjects for clinical trials.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Frontiers Media SA
Date: 22-09-2017
Publisher: Wiley
Date: 25-03-2020
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1111/AJT.15503
Publisher: Wiley
Date: 14-04-2020
DOI: 10.1002/BTM2.10159
Publisher: Elsevier BV
Date: 06-2018
Start Date: 2021
End Date: 2023
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2021
End Date: 02-2025
Amount: $540,762.00
Funder: Australian Research Council
View Funded Activity