scholarly journals Determination of the optimal bacteriophage dose to control Pseudomonas aeruginosa using evolutionary programming and stochastic kinetics

2016 ◽  
Author(s):  
Diana C Ardila ◽  
Juan D Castro ◽  
Angela V Holguín ◽  
Viviana Clavijo ◽  
Catalina Prada ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reverse Engineering ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Evolutionary Programming ◽  
Stochastic Simulations ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Promising Alternative

Phage-therapy is a promising alternative against pathogenic, multiple drug resistant bacteria. In this work we propose an algorithm to determine the optimal bacteriophage dose able to minimize a population of Pseudomonas aeruginosa. Reverse engineering was used to determine the kinetic parameters; subsequently, a bi-level optimization platform was implemented for a model based on evolutionary programming. Our prediction of optimal dose was tested in vitro with planktonic cultures of P. aeruginosa. From the data obtained, we conclude that reverse engineering and stochastic simulations are a useful approach to find optimal phage doses against pathogenic bacteria, an important step for the implementation of phage-therapy.

scholarly journals Determination of the optimal bacteriophage dose to control Pseudomonas aeruginosa using evolutionary programming and stochastic kinetics

2016 ◽  
Author(s):  
Diana C Ardila ◽  
Juan D Castro ◽  
Angela V Holguín ◽  
Viviana Clavijo ◽  
Catalina Prada ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reverse Engineering ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Evolutionary Programming ◽  
Stochastic Simulations ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Promising Alternative

Phage-therapy is a promising alternative against pathogenic, multiple drug resistant bacteria. In this work we propose an algorithm to determine the optimal bacteriophage dose able to minimize a population of Pseudomonas aeruginosa. Reverse engineering was used to determine the kinetic parameters; subsequently, a bi-level optimization platform was implemented for a model based on evolutionary programming. Our prediction of optimal dose was tested in vitro with planktonic cultures of P. aeruginosa. From the data obtained, we conclude that reverse engineering and stochastic simulations are a useful approach to find optimal phage doses against pathogenic bacteria, an important step for the implementation of phage-therapy.

scholarly journals Pseudomonas aeruginosa PAO 1 In Vitro Time–Kill Kinetics Using Single Phages and Phage Formulations—Modulating Death, Adaptation, and Resistance

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 877
Author(s):  
Ana Mafalda Pinto ◽  
Alberta Faustino ◽  
Lorenzo M. Pastrana ◽  
Manuel Bañobre-López ◽  
Sanna Sillankorva
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Chronic Infections ◽  
Swarming Motility ◽  
Resistance Development ◽  
Healthcare Settings ◽  
Time Kill

Pseudomonas aeruginosa is responsible for nosocomial and chronic infections in healthcare settings. The major challenge in treating P. aeruginosa-related diseases is its remarkable capacity for antibiotic resistance development. Bacteriophage (phage) therapy is regarded as a possible alternative that has, for years, attracted attention for fighting multidrug-resistant infections. In this work, we characterized five phages showing different lytic spectrums towards clinical isolates. Two of these phages were isolated from the Russian Microgen Sextaphage formulation and belong to the Phikmvviruses, while three Pbunaviruses were isolated from sewage. Different phage formulations for the treatment of P. aeruginosa PAO1 resulted in diversified time–kill outcomes. The best result was obtained with a formulation with all phages, prompting a lower frequency of resistant variants and considerable alterations in cell motility, resulting in a loss of 73.7% in swimming motility and a 79% change in swarming motility. These alterations diminished the virulence of the phage-resisting phenotypes but promoted their growth since most became insensitive to a single or even all phages. However, not all combinations drove to enhanced cell killings due to the competition and loss of receptors. This study highlights that more caution is needed when developing cocktail formulations to maximize phage therapy efficacy. Selecting phages for formulations should consider the emergence of phage-resistant bacteria and whether the formulations are intended for short-term or extended antibacterial application.

scholarly journals The Concerted Action of Two B3-Like Prophage Genes Excludes Superinfecting Bacteriophages by Blocking DNA Entry into Pseudomonas aeruginosa

2020 ◽  
Vol 94 (15) ◽  
Author(s):  
Marco Antonio Carballo-Ontiveros ◽  
Adrián Cazares ◽  
Pablo Vinuesa ◽  
Luis Kameyama ◽  
Gabriel Guarneros
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Alternative Therapy ◽  
Multidrug Resistant ◽  
Open Reading Frames ◽  
Resistant Bacteria ◽  
Content Type ◽  
Secondary Infections ◽  
Genes Encoding

ABSTRACT In this study, we describe seven vegetative phage genomes homologous to the historic phage B3 that infect Pseudomonas aeruginosa. Like other phage groups, the B3-like group contains conserved (core) and variable (accessory) open reading frames (ORFs) grouped at fixed regions in their genomes; however, in either case, many ORFs remain without assigned functions. We constructed lysogens of the seven B3-like phages in strain Ps33 of P. aeruginosa, a novel clinical isolate, and assayed the exclusion phenotype against a variety of temperate and virulent superinfecting phages. In addition to the classic exclusion conferred by the phage immunity repressor, the phenotype observed in B3-like lysogens suggested the presence of other exclusion genes. We set out to identify the genes responsible for this exclusion phenotype. Phage Ps56 was chosen as the study subject since it excluded numerous temperate and virulent phages. Restriction of the Ps56 genome, cloning of several fragments, and resection of the fragments that retained the exclusion phenotype allowed us to identify two core ORFs, so far without any assigned function, as responsible for a type of exclusion. Neither gene expressed separately from plasmids showed activity, but the concurrent expression of both ORFs is needed for exclusion. Our data suggest that phage adsorption occurs but that phage genome translocation to the host’s cytoplasm is defective. To our knowledge, this is the first report on this type of exclusion mediated by a prophage in P. aeruginosa. IMPORTANCE Pseudomonas aeruginosa is a Gram-negative bacterium frequently isolated from infected immunocompromised patients, and the strains are resistant to a broad spectrum of antibiotics. Recently, the use of phages has been proposed as an alternative therapy against multidrug-resistant bacteria. However, this approach may present various hurdles. This work addresses the problem that pathogenic bacteria may be lysogenized by phages carrying genes encoding resistance against secondary infections, such as those used in phage therapy. Discovering phage genes that exclude superinfecting phages not only assigns novel functions to orphan genes in databases but also provides insight into selection of the proper phages for use in phage therapy.

scholarly journals Multidrug Therapy and Evolution of Antibiotic Resistance: When Order Matters

2012 ◽  
Vol 78 (17) ◽  
pp. 6137-6142 ◽  
Author(s):  
Gabriel G. Perron ◽  
Sergey Kryazhimskiy ◽  
Daniel P. Rice ◽  
Angus Buckling
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Pathogenic Bacteria ◽  
Health Workers ◽  
Multiple Drug Resistance ◽  
Sequential Therapy ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Multidrug Therapy

ABSTRACTThe evolution of drug resistance among pathogenic bacteria has led public health workers to rely increasingly on multidrug therapy to treat infections. Here, we compare the efficacy of combination therapy (i.e., using two antibiotics simultaneously) and sequential therapy (i.e., switching two antibiotics) in minimizing the evolution of multidrug resistance. Usingin vitroexperiments, we show that the sequential use of two antibiotics againstPseudomonas aeruginosacan slow down the evolution of multiple-drug resistance when the two antibiotics are used in a specific order. A simple population dynamics model reveals that using an antibiotic associated with high costs of resistance first minimizes the chance of multidrug resistance evolution during sequential therapy under limited mutation supply rate. As well as presenting a novel approach to multidrug therapy, this work shows that costs of resistance not only influences the persistence of antibiotic-resistant bacteria but also plays an important role in the emergence of resistance.

scholarly journals Inhaled bacteriophage therapy in a porcine model of ventilator-associated pneumonia caused by pseudomonas aeruginosa.

2021 ◽  
Author(s):  
Antoine Guillon ◽  
Jeoffrey Pardessus ◽  
Guillaume L’Hostis ◽  
Cindy Fevre ◽  
Celine Barc ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Pseudomonas Aeruginosa ◽  
Phage Therapy ◽  
Antimicrobial Efficacy ◽  
Resistant Bacteria ◽  
Ventilator Associated Pneumonia ◽  
Bacteriophage Therapy ◽  
Log Reduction

Background and Purpose. Pseudomonas aeruginosa is a main cause of ventilator-associated pneumonia (VAP) with drug-resistant bacteria. Bacteriophage therapy has experienced resurgence to compensate for the limited development of novel antibiotics. However, phage therapy is limited to a compassionate use so far, resulting from lack of adequate studies in relevant pharmacological models. We used a pig model of VAP caused by P. aeruginosa that recapitulates essential features of human disease to study the antimicrobial efficacy of nebulized-phage therapy. Experimental Approach. (i) Lysis kinetic assays were performed to evaluate in vitro phage antibacterial efficacy against P. aeruginosa and select relevant combinations of lytic phages. (ii) The efficacy of the phage combinations was investigated in vivo (murine model of P. aeruginosa lung infection). (iii) We determined the optimal conditions to ensure efficient phage delivery by aerosol during mechanical ventilation. (iv) Lung antimicrobial efficacy of inhaled-phage therapy was evaluated in pigs, which were anesthetized, mechanically ventilated and infected with P. aeruginosa. Key Results. By selecting an active phage cocktail and optimizing aerosol delivery conditions, we were able to deliver high phage concentrations in the lungs, which resulted in a rapid and marked reduction in P. aeruginosa density (1.5 Log reduction, p<0.001). No phage was detected in the sera and urines throughout the experiment. Conclusion and Implications. Our findings demonstrated: (i) the feasibility of delivering large amounts of active phages by nebulization during mechanical ventilation, (ii) rapid control of in situ infection by inhaled bacteriophage in an experimental model of VAP with high translational value.

scholarly journals Comparative in vitro efficacy of eight essential oils as antibacterial agents against pathogenic bacteria isolated from pet-turtles

2018 ◽  
Vol 63 (No. 7) ◽  
pp. 335-343 ◽  
Author(s):  
BCJ De Silva ◽  
S. Hossain ◽  
SHMP Wimalasena ◽  
HNKS Pathirana ◽  
PS Dahanayake ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Antibacterial Agents ◽  
Bacterial Species ◽  
Antimicrobial Properties ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Drug Resistant Bacteria

Essential oils are plant extracts that have been used for their antimicrobial properties for centuries. The keeping of turtles as pets exhibits a growing trend worldwide but these animals are known to harbour a range of pathogenic bacteria. In the current study, we assessed eight essential oils as alternative antibacterial agents against nine species of pet turtle-borne Gram-negative bacteria, namely Aeromonas caviae, A. dhakensis, A. hydrophila, Citrobacter freundii, Morganella morganii, Proteus mirabilis, P. vulgaris, Pseudomonas aeruginosa and Salmonella enterica. Except for Pseudomonas aeruginosa, all other bacterial species showed high susceptibility to six essential oils, namely oregano, cinnamon, clove, lemongrass, lavender and eucalyptus oils in descending order of efficacy. Minimum inhibitory concentrations and minimum bactericidal concentrations values of the essential oils against all tested species except for P. aeruginosa showed low heterogeneity, showing that these essential oils can effectively control the growth of nearly all the tested. However, most of the tested bacteria were multiple-antibiotic-resistant as determined in the antibiotic disc diffusion test, with multiple-antibiotic-resistant index values of ≥ 0.2 for most of the strains. Therefore, with regards to their in vitro activity in controlling growth of multi-drug resistant bacteria, we can classify oregano, cinnamon, clove, lemongrass, lavender and eucalyptus essential oils as effective antibacterial agents. Thus, prospective application of these essential oils in controlling and treating these bacteria should be considered.

scholarly journals Parallel evolution of phage resistance - virulence trade - offs during in vitro and nasal Pseudomonas aeruginosa phage treatment

2021 ◽  
Author(s):  
Meaghan Castledine ◽  
Daniel Padfield ◽  
Pawel Sierocinski ◽  
Jesica Soria Pascual ◽  
Adam Hughes ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Evolutionary Dynamics ◽  
Phage Therapy ◽  
De Novo ◽  
Resistant Bacteria ◽  
Phage Resistance ◽  
Lower Growth ◽  
Trade Offs

With rising antibiotic resistance, there has been increasing interest in the treatment of pathogenic bacteria with bacteriophages (phage therapy). One limitation of phage therapy is the ease at which bacteria can evolve resistance. The negative effects of resistance may be partially mitigated when resistance results in reduced bacterial growth and virulence, or when phage coevolve to overcome resistance. Resistance evolution and its consequences are highly contingent on the particular combination of bacteria and phage and the ecological context they interact in, making therapeutic outcomes hard to predict. One solution might be to conduct ″in vitro evolutionary simulations″ using the bacteria-phage combinations specific to the therapeutic context. Here, we investigate parallels between in vitro experiments and in vivo dynamics in a human participant. Evolutionary dynamics were similar in vivo and in vitro, with high levels of de novo resistance evolving quickly with limited evidence of phage evolution. Moreover, resistant bacteria – evolved both in vitro and in vivo – had lower virulence when measured in an insect model. In vivo, this was linked to lower growth rates of resistant isolates, whereas in vitro isolates evolved greater biofilm production with phage resistance. Population sequencing suggests resistance was typically the result of selection on de novo mutations rather than sorting of existing variants in the population. These results highlight the speed at which resistance to phages can evolve in vivo, and that in vitro evolution may give useful insights for evolutionary outcomes in vivo.

scholarly journals Case Report: Chronic Bacterial Prostatitis Treated With Phage Therapy After Multiple Failed Antibiotic Treatments

2021 ◽  
Vol 12 ◽  
Author(s):  
Apurva Virmani Johri ◽  
Pranav Johri ◽  
Naomi Hoyle ◽  
Levan Pipia ◽  
Lia Nadareishvili ◽  
...  
Keyword(s):  
Antibiotic Treatment ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Bacterial Load ◽  
Prostate Gland ◽  
Resistant Bacteria ◽  
Bacteriophage Therapy ◽  
Chronic Bacterial Prostatitis ◽  
Promising Alternative ◽  
Bacterial Prostatitis

Background: Chronic Bacterial Prostatitis (CBP) is an inflammatory condition caused by a persistent bacterial infection of the prostate gland and its surrounding areas in the male pelvic region. It is most common in men under 50 years of age. It is a long-lasting and debilitating condition that severely deteriorates the patient’s quality of life. Anatomical limitations and antimicrobial resistance limit the effectiveness of antibiotic treatment of CBP. Bacteriophage therapy is proposed as a promising alternative treatment of CBP and related infections. Bacteriophage therapy is the use of lytic bacterial viruses to treat bacterial infections. Many cases of CBP are complicated by infections caused by both nosocomial and community acquired multidrug resistant bacteria. Frequently encountered strains include Vancomycin resistant Enterococci, Extended Spectrum Beta Lactam resistant Escherichia coli, other gram-positive organisms such as Staphylococcus and Streptococcus, Enterobacteriaceae such as Klebsiella and Proteus, and Pseudomonas aeruginosa, among others.Case Presentation: We present a patient with the typical manifestations of CBP. The patient underwent multiple courses of antibiotic treatment without any long-term resolution of his symptoms. Testing of prostatic secretion and semen samples revealed pathogenic bacteria in each case, which collectively included members of the Staphylococcal species such as Methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus haemolyticus, Enterococcus faecalis, and Streptococcus mitis, among others.Methods and Outcome: Bacteriophage preparations from the Eliava Institute were used to treat the patient after establishing phage sensitivity to the pathogenic bacteria. Significant improvements in symptoms and re-testing of samples after bacteriophage treatment indicated a reduction in the bacterial load and resolution of the infection.Discussion: The patient saw significant improvement of symptoms, and positive dynamics in bacterial titers and ultrasound controls after phage therapy. The failure of antibiotic therapy and subsequent success of bacteriophage therapy in treating chronic bacterial prostatitis shows the effectiveness of bacteriophages in controlling chronic infections in areas of low vascularity and anatomical complexity. These cases also highlight the efficacy of phages in overcoming antibiotic-resistant infections as well as biofilm infections.

Identification of a Potential Inhibitor Targeting MurC Ligase of the Drug Resistant Pseudomonas aeruginosa Strain through Structure-Based Virtual Screening Approach and In Vitro Assay

2019 ◽  
Vol 20 (14) ◽  
pp. 1203-1212
Author(s):  
Abdelmonaem Messaoudi ◽  
Manel Zoghlami ◽  
Zarrin Basharat ◽  
Najla Sadfi-Zouaoui
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virtual Screening ◽  
Homology Model ◽  
Generation Cephalosporin ◽  
World Health ◽  
Resistant Bacteria ◽  
Antimicrobial Drugs ◽  
Vitro Assay ◽  
Priority List

Background & Objective: Pseudomonas aeruginosa shows resistance to a large number of antibiotics, including carbapenems and third generation cephalosporin. According to the World Health Organization global report published in February 2017, Pseudomonas aeruginosa is on the priority list among resistant bacteria, for which new antibiotics are urgently needed. Peptidoglycan serves as a good target for the discovery of novel antimicrobial drugs. Methods: Biosynthesis of peptidoglycan is a multi-step process involving four mur enzymes. Among these enzymes, UDP-N-acetylmuramate-L-alanine ligase (MurC) is considered to be an excellent target for the design of new classes of antimicrobial inhibitors in gram-negative bacteria. Results: In this study, a homology model of Pseudomonas aeruginosa MurC ligase was generated and used for virtual screening of chemical compounds from the ZINC Database. The best screened inhibitor i.e. N, N-dimethyl-2-oxo-2,3-dihydro-1H-1,3-benzodiazole-5-sulfonamide was then validated experimentally through inhibition assay. Conclusion: The presented results based on combined computational and in vitro analysis open up new horizons for the development of novel antimicrobials against this pathogen.

scholarly journals Assessing the Molecular Targets and Mode of Action of Furanone C-30 on Pseudomonas aeruginosa Quorum Sensing

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1620
Author(s):  
Victor Markus ◽  
Karina Golberg ◽  
Kerem Teralı ◽  
Nazmi Ozer ◽  
Esti Kramarsky-Winter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Conformational Changes ◽  
Mode Of Action ◽  
Pathogenic Bacteria ◽  
Molecular Targets ◽  
Resistant Bacteria ◽  
Public Healthcare ◽  
C 30

Quorum sensing (QS), a sophisticated system of bacterial communication that depends on population density, is employed by many pathogenic bacteria to regulate virulence. In view of the current reality of antibiotic resistance, it is expected that interfering with QS can address bacterial pathogenicity without stimulating the incidence of resistance. Thus, harnessing QS inhibitors has been considered a promising approach to overriding bacterial infections and combating antibiotic resistance that has become a major threat to public healthcare around the globe. Pseudomonas aeruginosa is one of the most frequent multidrug-resistant bacteria that utilize QS to control virulence. Many natural compounds, including furanones, have demonstrated strong inhibitory effects on several pathogens via blocking or attenuating QS. While the natural furanones show no activity against P. aeruginosa, furanone C-30, a brominated derivative of natural furanone compounds, has been reported to be a potent inhibitor of the QS system of the notorious opportunistic pathogen. In the present study, we assess the molecular targets and mode of action of furanone C-30 on P. aeruginosa QS system. Our results suggest that furanone C-30 binds to LasR at the ligand-binding site but fails to establish interactions with the residues crucial for the protein’s productive conformational changes and folding, thus rendering the protein dysfunctional. We also show that furanone C-30 inhibits RhlR, independent of LasR, suggesting a complex mechanism for the agent beyond what is known to date.

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