scholarly journals Antibiotic Therapy Using Phage Depolymerases: Robustness Across a Range of Conditions

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 622 ◽  
Author(s):  
Han Lin ◽  
Matthew Paff ◽  
Ian Molineux ◽  
James Bull
Keyword(s):  
Antibacterial Agents ◽  
Treatment Success ◽  
Resistant Bacteria ◽  
Success Rates ◽  
Therapeutic Success ◽  
Delayed Treatment ◽  
Model Studies ◽  
Degrading Enzymes ◽  
K1 Capsule

Phage-derived depolymerases directed against bacterial capsules are showing therapeutic promise in various animal models of infection. However, individual animal model studies are often constrained by use of highly specific protocols, such that results may not generalize to even slight modifications. Here we explore the robustness of depolymerase therapies shown to succeed in a previous study of mice. Treatment success rates were reduced by treatment delay, more so for some enzymes than others: K1- and K5 capsule-degrading enzymes retained partial efficacy on delay, while K30 depolymerase did not. Phage were superior to enzymes under delayed treatment only for K1. Route of administration (intramuscular versus intraperitoneal) mattered for success of K1E, possibly for K1F, not for K1H depolymerase. Significantly, K1 capsule-degrading enzymes proved highly successful when using immune-suppressed, leukopenic mice, even with delayed treatment. Evolution of bacteria resistant to K1-degrading enzymes did not thwart therapeutic success in leukopenic mice, likely because resistant bacteria were avirulent. In combination with previous studies these results continue to support the efficacy of depolymerases as antibacterial agents in vivo, but system-specific details are becoming evident.

scholarly journals Promises and Pitfalls of In Vivo Evolution to Improve Phage Therapy

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1083 ◽  
Author(s):  
James J. Bull ◽  
Bruce R. Levin ◽  
Ian J. Molineux
Keyword(s):  
Decay Rate ◽  
Bacterial Infections ◽  
Computational Models ◽  
Phage Therapy ◽  
Treatment Success ◽  
Medical Intervention ◽  
Resistant Bacteria ◽  
Therapeutic Success ◽  
Phage Growth

Phage therapy is the use of bacterial viruses (phages) to treat bacterial infections, a medical intervention long abandoned in the West but now experiencing a revival. Currently, therapeutic phages are often chosen based on limited criteria, sometimes merely an ability to plate on the pathogenic bacterium. Better treatment might result from an informed choice of phages. Here we consider whether phages used to treat the bacterial infection in a patient may specifically evolve to improve treatment on that patient or benefit subsequent patients. With mathematical and computational models, we explore in vivo evolution for four phage properties expected to influence therapeutic success: generalized phage growth, phage decay rate, excreted enzymes to degrade protective bacterial layers, and growth on resistant bacteria. Within-host phage evolution is strongly aligned with treatment success for phage decay rate but only partially aligned for phage growth rate and growth on resistant bacteria. Excreted enzymes are mostly not selected for treatment success. Even when evolution and treatment success are aligned, evolution may not be rapid enough to keep pace with bacterial evolution for maximum benefit. An informed use of phages is invariably superior to naive reliance on within-host evolution.

scholarly journals Resistance and Adaptation of Bacteria to Non-Antibiotic Antibacterial Agents: Physical Stressors, Nanoparticles, and Bacteriophages

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 435
Author(s):  
Sada Raza ◽  
Kinga Matuła ◽  
Sylwia Karoń ◽  
Jan Paczesny
Keyword(s):  
Antimicrobial Resistance ◽  
Antibacterial Agents ◽  
Uv Light ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Physical Factors ◽  
Defense Systems ◽  
Drug Resistant Bacteria

Antimicrobial resistance is a significant threat to human health worldwide, forcing scientists to explore non-traditional antibacterial agents to support rapid interventions and combat the emergence and spread of drug resistant bacteria. Many new antibiotic-free approaches are being developed while the old ones are being revised, resulting in creating unique solutions that arise at the interface of physics, nanotechnology, and microbiology. Specifically, physical factors (e.g., pressure, temperature, UV light) are increasingly used for industrial sterilization. Nanoparticles (unmodified or in combination with toxic compounds) are also applied to circumvent in vivo drug resistance mechanisms in bacteria. Recently, bacteriophage-based treatments are also gaining momentum due to their high bactericidal activity and specificity. Although the number of novel approaches for tackling the antimicrobial resistance crisis is snowballing, it is still unclear if any proposed solutions would provide a long-term remedy. This review aims to provide a detailed overview of how bacteria acquire resistance against these non-antibiotic factors. We also discuss innate bacterial defense systems and how bacteriophages have evolved to tackle them.

scholarly journals Different Therapeutic Outcomes of Benznidazole and VNI Treatments in Different Genders in Mouse Experimental Models of Trypanosoma cruzi Infection

2015 ◽  
Vol 59 (12) ◽  
pp. 7564-7570 ◽  
Author(s):  
F. H. Guedes-da-Silva ◽  
D. G. J. Batista ◽  
C. F. da Silva ◽  
M. B. Meuser ◽  
M. R. Simões-Silva ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Chagas Disease ◽  
Treatment Success ◽  
Experimental Models ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
Success Rates ◽  
Content Type ◽  
Drug Candidates

ABSTRACTThe lack of translation between preclinical assays and clinical trials for novel therapies for Chagas disease (CD) indicates a need for more feasible and standardized protocols and experimental models. Here, we investigated the effects of treatment with benznidazole (Bz) and with the potent experimentalT. cruziCYP51 inhibitor VNI in mouse models of Chagas disease by using different animal genders and parasite strains and employing distinct types of therapeutic schemes. Our findings confirm that female mice are less vulnerable to the infection than males, show that male models are less susceptible to treatment with both Bz and VNI, and thus suggest that male models are much more suitable for selection of the most promising antichagasic agents. Additionally, we have found that preventive protocols (compound given at 1 dpi) result in higher treatment success rates, which also should be avoided during advanced steps ofin vivotrials of novel anti-T. cruzidrug candidates. Another consideration is the relevance of immunosuppression methods in order to verify the therapeutic profile of novel compounds, besides the usefulness of molecular diagnostic tools (quantitative PCR) to ascertain compound efficacy in experimental animals. Our study aims to contribute to the development of more reliable methods and decision gates forin vivoassays of novel antiparasitic compounds in order to move them from preclinical to clinical trials for CD.

scholarly journals Promises and pitfalls of in vivo evolution to improve phage therapy

2019 ◽  
Author(s):  
James J Bull ◽  
Bruce R. Levin ◽  
Ian J. Molineux
Keyword(s):  
Bacterial Infections ◽  
Computational Models ◽  
Phage Therapy ◽  
Informed Choice ◽  
Resistant Bacteria ◽  
Prior History ◽  
Therapeutic Success ◽  
History Of ◽  
History Of Use

Abstract(Background) Phage therapy is the use of bacterial viruses (phages) to treat bacterial infections. Phages lack the broad host ranges of antibiotics, so individual phages are often used with no prior history of use in treatment. Therapeutic phages are thus often chosen based on limited criteria, sometimes merely an ability to plate on the pathogenic bacterium. It is possible that better treatment outcomes might be obtained from an informed choice of phages. Here we consider whether phages used to treat the bacterial infection in a patient might specifically evolve to improve treatment. Phages recovered from the patient could then serve as a source of improved phages or cocktails for use on subsequent patients. (Methods) With the aid of mathematical and computational models, we explore this possibility for four phage properties expected to promote therapeutic success: in vivo growth, phage decay rate, overcoming resistant bacteria, and enzyme activity to degrade protective bacterial layers. (Results) Phage evolution only sometimes works in favor of treatment, and even in those cases, intrinsic phage dynamics in the patient are usually not ideal. An informed use of phages is invariably superior to reliance on within-host evolution and dynamics, although the extent of this benefit varies with the application.

scholarly journals Antibacterial Activity of Various Extracts of Averrhoa bilimbi against Multidrug Resistant Bacteria

2020 ◽  
Vol 12 (2) ◽  
pp. 163-168
Author(s):  
Muhammad Evy Prastiyanto ◽  
Fandhi Adi Wardoyo ◽  
Wildiani Wilson ◽  
Sri Darmawati
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Water Extract ◽  
Ethanolic Extract ◽  
Antibacterial Activities ◽  
Multi Drug Resistance ◽  
Resistant Bacteria ◽  
Agar Well Diffusion Assay ◽  
Diffusion Assay

The multi-drug resistance (MDR) bacteria is a global health problem that causes high mortality every year. Therefore, novel antibacterial agents are needed from natural biological sources. This research aimed to investigate the antibacterial activities of various crude extracts of Averrhoa bilimbi against MDR bacteria. The antibacterial activity was calculated based on the use agar well diffusion assay and the minimum bactericidal concentration (MBC) using Mueller–Hinton broth in a microdilution method. Bacteria from wells were subcultured using inoculating loop onto a 5% sheep BAP. The best antibacterial activity, calculated as the most widely inhibitory zone and the smallest MBC values. The ethanolic extract showed antibacterial activity against the all MDR bacterial test in the agar well diffusion assay (10-14.5 mm inhibition diameter). The MBC of water extract against ESβL + CR Pseudomonas aeruginosa showed the best antibacterial activity (12.5 mg/mL). The fruit of bilimbi was shown to be potentially developed as antibacterial agents, especially for MDR strains. Further in vivo research and discovery of action mode are needed to shed light on their antibacterial effects. This study can provide new information about the benefits of bilimbi as a source of natural antibacterial againts MDR-bacteria

Potential for Treatment of Neurodegenerative Diseases with Natural Products or Synthetic Compounds that Stabilize Microtubules

2020 ◽  
Vol 26 (35) ◽  
pp. 4362-4372
Author(s):  
John H. Miller ◽  
Viswanath Das
Keyword(s):  
Natural Products ◽  
Neurodegenerative Diseases ◽  
In Vivo Models ◽  
Synthetic Compounds ◽  
Stabilizing Agents ◽  
Animal Models Of Disease ◽  
Model Studies ◽  
Models Of Disease

No effective therapeutics to treat neurodegenerative diseases exist, despite significant attempts to find drugs that can reduce or rescue the debilitating symptoms of tauopathies such as Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis, or Pick’s disease. A number of in vitro and in vivo models exist for studying neurodegenerative diseases, including cell models employing induced-pluripotent stem cells, cerebral organoids, and animal models of disease. Recent research has focused on microtubulestabilizing agents, either natural products or synthetic compounds that can prevent the axonal destruction caused by tau protein pathologies. Although promising results have come from animal model studies using brainpenetrant natural product microtubule-stabilizing agents, such as paclitaxel analogs that can access the brain, epothilones B and D, and other synthetic compounds such as davunetide or the triazolopyrimidines, early clinical trials in humans have been disappointing. This review aims to summarize the research that has been carried out in this area and discuss the potential for the future development of an effective microtubule stabilizing drug to treat neurodegenerative disease.

Effects of Probiotics in the Management of Infected Chronic Wounds: From Cell Culture to Human Studies

2020 ◽  
Vol 15 (3) ◽  
pp. 193-206
Author(s):  
Brognara Lorenzo ◽  
Salmaso Luca ◽  
Mazzotti Antonio ◽  
Di M. Alberto ◽  
Faldini Cesare ◽  
...  
Keyword(s):  
Chronic Wounds ◽  
Animal Experiments ◽  
Multidrug Resistant ◽  
Preliminary Evidence ◽  
Human Studies ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Keywords Probiotics

Background: Chronic wounds are commonly associated with polymicrobial biofilm infections. In the last years, the extensive use of antibiotics has generated several antibiotic-resistant variants. To overcome this issue, alternative natural treatments have been proposed, including the use of microorganisms like probiotics. The aim of this manuscript was to review current literature concerning the application of probiotics for the treatment of infected chronic wounds. Methods: Relevant articles were searched in the Medline database using PubMed and Scholar, using the keywords “probiotics” and “wound” and “injuries”, “probiotics” and “wound” and “ulcer”, “biofilm” and “probiotics” and “wound”, “biofilm” and “ulcer” and “probiotics”, “biofilm” and “ulcer” and “probiotics”, “probiotics” and “wound”. Results: The research initially included 253 articles. After removal of duplicate studies, and selection according to specific inclusion and exclusion criteria, 19 research articles were included and reviewed, accounting for 12 in vitro, 8 in vivo studies and 2 human studies (three articles dealing with animal experiments included also in vitro testing). Most of the published studies about the effects of probiotics for the treatment of infected chronic wounds reported a partial inhibition of microbial growth, biofilm formation and quorum sensing. Discussion: The application of probiotics represents an intriguing option in the treatment of infected chronic wounds with multidrug-resistant bacteria; however, current results are difficult to compare due to the heterogeneity in methodology, laboratory techniques, and applied clinical protocols. Lactobacillus plantarum currently represents the most studied strain, showing a positive application in burns compared to guideline treatments, and an additional mean in chronic wound infections. Conclusions: Although preliminary evidence supports the use of specific strains of probiotics in certain clinical settings such as infected chronic wounds, large, long-term clinical trials are still lacking, and further research is needed.

scholarly journals Aerosol-based antimicrobial photoinactivation in the lungs: an action spectrum study

2021 ◽  
Author(s):  
Chiara Treghini ◽  
Alfonso Dell’Accio ◽  
Franco Fusi ◽  
Giovanni Romano
Keyword(s):  
Light Source ◽  
A Priori ◽  
Action Spectrum ◽  
Multidrug Resistant ◽  
Theoretical Modelling ◽  
Resistant Bacteria ◽  
Lung Infections ◽  
Killing Action ◽  
Definition Of

AbstractChronic lung infections are among the most diffused human infections, being often associated with multidrug-resistant bacteria. In this framework, the European project “Light4Lungs” aims at synthesizing and testing an inhalable light source to control lung infections by antimicrobial photoinactivation (aPDI), addressing endogenous photosensitizers only (porphyrins) in the representative case of S. aureus and P. aeruginosa. In the search for the best emission characteristics for the aerosolized light source, this work defines and calculates the photo-killing action spectrum for lung aPDI in the exemplary case of cystic fibrosis. This was obtained by applying a semi-theoretical modelling with Monte Carlo simulations, according to previously published methodology related to stomach infections and applied to the infected trachea, bronchi, bronchioles and alveoli. In each of these regions, the two low and high oxygen concentration cases were considered to account for the variability of in vivo conditions, together with the presence of endogenous porphyrins and other relevant absorbers/diffusers inside the illuminated biofilm/mucous layer. Furthermore, an a priori method to obtain the “best illumination wavelengths” was defined, starting from maximizing porphyrin and light absorption at any depth. The obtained action spectrum is peaked at 394 nm and mostly follows porphyrin extinction coefficient behavior. This is confirmed by the results from the best illumination wavelengths, which reinforces the robustness of our approach. These results can offer important indications for the synthesis of the aerosolized light source and definition of its most effective emission spectrum, suggesting a flexible platform to be considered in further applications.

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

scholarly journals Impact on Antibiotic Resistance, Therapeutic Success, and Control of Side Effects in Therapeutic Drug Monitoring (TDM) of Daptomycin: A Scoping Review

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 263
Author(s):  
Carolina Osorio ◽  
Laura Garzón ◽  
Diego Jaimes ◽  
Edwin Silva ◽  
Rosa-Helena Bustos
Keyword(s):  
Side Effects ◽  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Bacterial Resistance ◽  
Plasma Concentrations ◽  
Resistant Bacteria ◽  
Therapeutic Drug ◽  
Therapeutic Success ◽  
Favorable Clinical Outcome ◽  
And Control

Antimicrobial resistance (AR) is a problem that threatens the search for adequate safe and effective antibiotic therapy against multi-resistant bacteria like methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococci (VRE) and Clostridium difficile, among others. Daptomycin is the treatment of choice for some infections caused by Gram-positive bacteria, indicated most of the time in patients with special clinical conditions where its high pharmacokinetic variability (PK) does not allow adequate plasma concentrations to be reached. The objective of this review is to describe the data available about the type of therapeutic drug monitoring (TDM) method used and described so far in hospitalized patients with daptomycin and to describe its impact on therapeutic success, suppression of bacterial resistance, and control of side effects. The need to create worldwide strategies for the appropriate use of antibiotics is clear, and one of these is the performance of therapeutic drug monitoring (TDM). TDM helps to achieve a dose adjustment and obtain a favorable clinical outcome for patients by measuring plasma concentrations of an administered drug, making a rational interpretation guided by a predefined concentration range, and, thus, adjusting dosages individually.

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