scholarly journals Friends or Foes? Rapid Determination of Dissimilar Colistin and Ciprofloxacin Antagonism of Pseudomonas aeruginosa Phages

2021 ◽  
Vol 14 (11) ◽  
pp. 1162
Author(s):  
Katarzyna M. Danis-Wlodarczyk ◽  
Alice Cai ◽  
Anna Chen ◽  
Marissa R. Gittrich ◽  
Matthew B. Sullivan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Rapid Determination ◽  
Treatment Success ◽  
Phage Infection ◽  
Virion Production ◽  
Metabolic Activities ◽  
Therapy Studies ◽  
The Impact

Phage therapy is a century-old technique employing viruses (phages) to treat bacterial infections, and in the clinic it is often used in combination with antibiotics. Antibiotics, however, interfere with critical bacterial metabolic activities that can be required by phages. Explicit testing of antibiotic antagonism of phage infection activities, though, is not a common feature of phage therapy studies. Here we use optical density-based ‘lysis-profile’ assays to assess the impact of two antibiotics, colistin and ciprofloxacin, on the bactericidal, bacteriolytic, and new-virion-production activities of three Pseudomonas aeruginosa phages. Though phages and antibiotics in combination are more potent in killing P. aeruginosa than either acting alone, colistin nevertheless substantially interferes with phage bacteriolytic and virion-production activities even at its minimum inhibitory concentration (1× MIC). Ciprofloxacin, by contrast, has little anti-phage impact at 1× or 3× MIC. We corroborate these results with more traditional measures, particularly colony-forming units, plaque-forming units, and one-step growth experiments. Our results suggest that ciprofloxacin could be useful as a concurrent phage therapy co-treatment especially when phage replication is required for treatment success. Lysis-profile assays also appear to be useful, fast, and high-throughput means of assessing antibiotic antagonism of phage infection activities.

scholarly journals In vitro analysis of colistin and ciprofloxacin antagonism of Pseudomonas aeruginosa phage PEV2 infection activities

2020 ◽  
Author(s):  
Katarzyna Danis-Wlodarczyk ◽  
Alice Cai ◽  
Anna Chen ◽  
Marissa Gittrich ◽  
Matthew B. Sullivan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Phage Infection ◽  
Broth Culture ◽  
Virion Production ◽  
Infection Processes ◽  
Vitro Analysis ◽  
Therapy Studies

AbstractPhage therapy is a century-old technique employing viruses (phages) to treat bacterial infections. In the clinic, phage therapy often is used in combination with antibiotics. Antibiotics, however, interfere with critical bacterial activities, such as DNA and protein synthesis, which also are required for phage infection processes. Resulting antagonistic impacts of antibiotics on phages nevertheless are not commonly determined in association with phage therapy studies using standard, planktonic approaches. Here we assess the antagonistic impact of two antibiotics, colistin and ciprofloxacin, on the bactericidal, bacteriolytic, and new virion production activities of Pseudomonas aeruginosa podovirus PEV2, using a broth culture, optical density-based ‘lysis profile’ assay. Though phage-antibiotic combinations were more potent in reducing cell viability than phages or antibiotics alone, colistin substantially interfered with phage PEV2 bacteriolytic and virion-production activities at minimum inhibitory concentration (MIC). Ciprofloxacin, by contrast, had no such impact at 1x MIC or 3x MIC. At higher but still clinically relevant concentrations (9× MIC) burst sizes were still significant (~30 phages/infected bacterium). We corroborated these lysis profile results by more traditional measurements (colony forming units, plaque forming units, one-step growth experiments) and two other P. aeruginosa phages. To our knowledge this is the first study in which detailed antibiotic impact on P. aeruginosa phage infection activities has been determined under conditions similar to those used to determine antibiotic MICs and could point especially to ciprofloxacin as a minimally antagonistic phage therapy co-treatment of P. aeruginosa infections.

scholarly journals Light-Mediated Decreases in Cyclic di-GMP Levels Inhibit Structure Formation in Pseudomonas aeruginosa Biofilms

2020 ◽  
Vol 202 (14) ◽  
Author(s):  
Lisa Juliane Kahl ◽  
Alexa Price-Whelan ◽  
Lars E. P. Dietrich
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Research Attention ◽  
Content Type ◽  
Dependent Inhibition ◽  
Matrix Production ◽  
Biofilm Development ◽  
The Impact

ABSTRACT Light is known to trigger regulatory responses in diverse organisms, including slime molds, animals, plants, and phototrophic bacteria. However, light-dependent processes in nonphototrophic bacteria, and those of pathogens in particular, have received comparatively little research attention. In this study, we examined the impact of light on multicellular development in Pseudomonas aeruginosa, a leading cause of biofilm-based bacterial infections. We grew P. aeruginosa strain PA14 in a colony morphology assay and found that growth under prolonged exposure to low-intensity blue light inhibited biofilm matrix production and thereby the formation of vertical biofilm structures (i.e., “wrinkles”). Light-dependent inhibition of biofilm wrinkling was correlated with low levels of cyclic di-GMP (c-di-GMP), consistent with the role of this signal in stimulating matrix production. A screen of enzymes with the potential to catalyze c-di-GMP synthesis or degradation identified c-di-GMP phosphodiesterases that contribute to light-dependent inhibition of biofilm wrinkling. One of these, RmcA, was previously characterized by our group for its role in mediating the effect of redox-active P. aeruginosa metabolites called phenazines on biofilm wrinkle formation. Our results suggest that an RmcA sensory domain that is predicted to bind a flavin cofactor is involved in light-dependent inhibition of wrinkling. Together, these findings indicate that P. aeruginosa integrates information about light exposure and redox state in its regulation of biofilm development. IMPORTANCE Light exposure tunes circadian rhythms, which modulate the immune response and affect susceptibility to infection in plants and animals. Though molecular responses to light are defined for model plant and animal hosts, analogous pathways that function in bacterial pathogens are understudied. We examined the response to light exposure in biofilms (matrix-encased multicellular assemblages) of the nonphotosynthetic bacterium Pseudomonas aeruginosa. We found that light at intensities that are not harmful to human cells inhibited biofilm maturation via effects on cellular signals. Because biofilm formation is a critical factor in many types of P. aeruginosa infections, including burn wound infections that may be exposed to light, these effects could be relevant for pathogenicity.

scholarly journals A Multifaceted Study of Pseudomonas aeruginosa Shutdown by Virulent Podovirus LUZ19

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Rob Lavigne ◽  
Elke Lecoutere ◽  
Jeroen Wagemans ◽  
William Cenens ◽  
Abram Aertsen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Genome ◽  
Phage Infection ◽  
Two Dimensional ◽  
Viral Control ◽  
Content Type ◽  
Bacterial Physiology ◽  
Phage Development ◽  
Bacterial Viruses ◽  
The Impact

ABSTRACT In contrast to the rapidly increasing knowledge on genome content and diversity of bacterial viruses, insights in intracellular phage development and its impact on bacterial physiology are very limited. We present a multifaceted study combining quantitative PCR (qPCR), microarray, RNA-seq, and two-dimensional gel electrophoresis (2D-GE), to obtain a global overview of alterations in DNA, RNA, and protein content in Pseudomonas aeruginosa PAO1 cells upon infection with the strictly lytic phage LUZ19. Viral genome replication occurs in the second half of the phage infection cycle and coincides with degradation of the bacterial genome. At the RNA level, there is a sharp increase in viral mRNAs from 23 to 60% of all transcripts after 5 and 15 min of infection, respectively. Although microarray analysis revealed a complex pattern of bacterial up- and downregulated genes, the accumulation of viral mRNA clearly coincides with a general breakdown of abundant bacterial transcripts. Two-dimensional gel electrophoretic analyses shows no bacterial protein degradation during phage infection, and seven stress-related bacterial proteins appear. Moreover, the two most abundantly expressed early and late-early phage proteins, LUZ19 gene product 13 (Gp13) and Gp21, completely inhibit P. aeruginosa growth when expressed from a single-copy plasmid. Since Gp13 encodes a predicted GNAT acetyltransferase, this observation points at a crucial but yet unexplored level of posttranslational viral control during infection. IMPORTANCE Massive genome sequencing has led to important insights into the enormous genetic diversity of bacterial viruses (bacteriophages). However, for nearly all known phages, information on the impact of the phage infection on host physiology and intracellular phage development is scarce. This aspect of phage research should be revitalized, as phages evolved genes which can shut down or redirect bacterial processes in a very efficient way, which can be exploited towards antibacterial design. In this context, we initiated a study of the human opportunistic pathogen Pseudomonas aeruginosa under attack by one its most common predators, the Phikmvlikevirus. By analyzing various stages of infection at different levels, this study uncovers new features of phage infection, representing a cornerstone for future studies on members of this phage genus.

scholarly journals Resistance Evolution against Phage Combinations Depends on the Timing and Order of Exposure

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Rosanna C. T. Wright ◽  
Ville-Petri Friman ◽  
Margaret C. M. Smith ◽  
Michael A. Brockhurst
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Fitness Costs ◽  
Evolutionary Trajectory ◽  
Promising Alternative ◽  
Content Type ◽  
Resistance Evolution

ABSTRACTPhage therapy is a promising alternative to chemotherapeutic antibiotics for the treatment of bacterial infections. However, despite recent clinical uses of combinations of phages to treat multidrug-resistant infections, a mechanistic understanding of how bacteria evolve resistance against multiple phages is lacking, limiting our ability to deploy phage combinations optimally. Here, we show, usingPseudomonas aeruginosaand pairs of phages targeting shared or distinct surface receptors, that the timing and order of phage exposure determine the strength, cost, and mutational basis of resistance. Whereas sequential exposure allowed bacteria to acquire multiple resistance mutations effective against both phages, this evolutionary trajectory was prevented by simultaneous exposure, resulting in quantitatively weaker resistance. The order of phage exposure determined the fitness costs of sequential resistance, such that certain sequential orders imposed much higher fitness costs than the same phage pair in the reverse order. Together, these data suggest that phage combinations can be optimized to limit the strength of evolved resistances while maximizing their associated fitness costs to promote the long-term efficacy of phage therapy.IMPORTANCEGlobally rising rates of antibiotic resistance have renewed interest in phage therapy where combinations of phages have been successfully used to treat multidrug-resistant infections. To optimize phage therapy, we first need to understand how bacteria evolve resistance against combinations of multiple phages. Here, we use simple laboratory experiments and genome sequencing to show that the timing and order of phage exposure determine the strength, cost, and mutational basis of resistance evolution in the opportunistic pathogenPseudomonas aeruginosa. These findings suggest that phage combinations can be optimized to limit the emergence and persistence of resistance, thereby promoting the long-term usefulness of phage therapy.

scholarly journals Novel Lytic Phages Protect Cells and Mice against Pseudomonas aeruginosa Infection

2021 ◽  
Author(s):  
Feng Chen ◽  
Xingjun Cheng ◽  
Jianbo Li ◽  
Xiefang Yuan ◽  
Xiuhua Huang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mouse Models ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Inflammatory Responses ◽  
Multi Drug Resistance ◽  
Bacterial Strains ◽  
Genetic Traits

With the fast emergence of serious antibiotic resistance and the lagged discovery of novel antibacterial drugs, phage therapy for pathogenic bacterial infections has acquired great attention in the clinics. However, development of therapeutic phages also faces tough challenges, such as laborious screening and time to generate effective phage drugs since each phage may only lyse a narrow scope of bacterial strains. Identifying highly effective phages with broad host ranges is crucial for improving phage therapy. Here, we isolated and characterized several lytic phages from various environments specific for Pseudomonas aeruginosa by testing their growth, invasion, host ranges, and potential for killing targeted bacteria. Importantly, we identified several therapeutic phages (HX1, PPY9, and TH15) with broad host ranges to lyse laboratory strains and clinical isolates of P. aeruginosa with multi-drug resistance (MDR) both in vitro and in mouse models. In addition, we analyzed critical genetic traits related to the high-level broad host coverages by genome sequencing and subsequent computational analysis against known phages. Collectively, our findings establish that these novel phages may have potential for further development as therapeutic options for patients who fail to respond to conventional treatments. IMPORTANCE Novel lytic phages isolated from various environmental settings were systematically characterized for their critical genetic traits, morphology structures, host ranges against laboratory strains and clinical multi-drug resistant (MDR) Pseudomonas aeruginosa, and antibacterial capacity both in vitro and in mouse models. First, we characterized the genetic traits and compared with other existing phages. Furthermore, we utilized acute pneumonia induced by laboratorial strain PAO1, and W19, an MDR clinical isolate and chronic pneumonia by agar beads laden with FDR1, a mucoid phenotype strain isolated from the sputum of a cystic fibrosis (CF) patient. Consequently, we found that these phages not only suppress bacteria in vitro but also significantly reduce the infection symptom and disease progression in vivo, including lowered bug burdens, inflammatory responses and lung injury in mice, suggesting that they may be further developed as therapeutic agents against MDR P. aeruginosa.

scholarly journals Acute SARS-CoV-2 infection is associated with an expansion of bacteria pathogens in the nose including Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Nicholas S Rhoades ◽  
Amanda Pinski ◽  
Alisha N Monsibais ◽  
Allen Jankeel ◽  
Brianna M Doratt ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Health Care Providers ◽  
Bacterial Infections ◽  
Neuronal Damage ◽  
Medical Center ◽  
Bacterial Pathogens ◽  
Hospital Environment ◽  
Respiratory Pathogens ◽  
Care Providers ◽  
The Impact

Much of the research conducted on SARS-CoV-2 and COVID-19 has focused on the systemic host response, especially that generated by severely ill patients. Very few studies have investigated the impact of acute SARS-CoV-2 within the nasopharynx, the site of initial infection and viral replication. In this study we profiled changes in the nasal microbial communities as well as in host transcriptional profile during acute SARS-CoV-2 infection using 16S amplicon sequencing and RNA sequencing. These analyses were coupled to viral genome sequencing. Our microbiome analysis revealed that the nasal microbiome of COVID patients was unique and was marked by an expansion of bacterial pathogens. Some of these microbes (i.e. Acinetobacter) were shared with COVID negative health care providers from the same medical center but absent in COVID negative outpatients seeking care at the same institutions suggesting acquisition of nosocomial respiratory pathogens. Specifically, we report a distinct increase in the prevalence and abundance of the pathogen Pseudomonas aeruginosa in COVID patients that correlated with viral RNA load. These data suggest that the inflammatory environment caused by SARS-CoV-2 infection and potentially exposure to the hospital environment leads to an expansion of bacterial pathogens in the nasal cavity that could contribute to increased incidence of secondary bacterial infections. Additionally, we observed a robust host transcriptional response in the nasal epithelia of COVID patients, indicative of an antiviral innate immune repones and neuronal damage. Finally, analysis of viral genomes did not reveal an association between viral loads and viral sequences.

scholarly journals Phage infection and sub-lethal antibiotic exposure mediate Enterococcus faecalis type VII secretion system dependent inhibition of bystander bacteria

2020 ◽  
Author(s):  
Anushila Chatterjee ◽  
Julia L. E. Willett ◽  
Gary M. Dunny ◽  
Breck A. Duerkop
Keyword(s):  
Bacterial Infections ◽  
Phage Therapy ◽  
Secretion System ◽  
Phage Infection ◽  
Collateral Damage ◽  
Bacterial Cells ◽  
Antibiotic Exposure ◽  
Type Vii Secretion ◽  
Type Vii Secretion System ◽  
Polymicrobial Communities

AbstractBacteriophages (phages) are being considered as alternative therapeutics for the treatment of multidrug resistant bacterial infections. Considering phages have narrow host-ranges, it is generally accepted that therapeutic phages will have a marginal impact on non-target bacteria. We have discovered that lytic phage infection induces transcription of type VIIb secretion system (T7SS) genes in the pathobiont Enterococcus faecalis. Membrane damage during phage infection induces T7SS gene expression resulting in cell contact dependent antagonism of different Gram positive bystander bacteria. Deletion of essB, a T7SS structural component, abrogates phage-mediated killing of bystanders. A predicted immunity gene confers protection against T7SS mediated inhibition, and disruption of its upstream LXG toxin gene rescues growth of E. faecalis and Staphylococcus aureus bystanders. Phage induction of T7SS gene expression and bystander inhibition requires IreK, a serine/threonine kinase, and OG1RF_11099, a predicted GntR-family transcription factor. Additionally, sub-lethal doses of membrane targeting and DNA damaging antibiotics activated T7SS expression independent of phage infection, triggering T7SS antibacterial activity against bystander bacteria. Our findings highlight how phage infection and antibiotic exposure of a target bacterium can affect non-target bystander bacteria and implies that therapies beyond antibiotics, such as phage therapy, could impose collateral damage to polymicrobial communities.Author SummaryRenewed interest in phages as alternative therapeutics to combat multi-drug resistant bacterial infections, highlights the importance of understanding the consequences of phage-bacteria interactions in the context of microbial communities. Although it is well established that phages are highly specific for their host bacterium, there is no clear consensus on whether or not phage infection (and thus phage therapy) would impose collateral damage to non-target bacteria in polymicrobial communities. Here we provide direct evidence of how phage infection of a clinically relevant pathogen triggers an intrinsic type VII secretion system (T7SS) antibacterial response that consequently restricts the growth of neighboring bacterial cells that are not susceptible to phage infection. Phage induction of T7SS activity is a stress response and in addition to phages, T7SS antagonism can be induced using sub-inhibitory concentrations of antibiotics that facilitate membrane or DNA damage. Together these data show that a bacterial pathogen responds to diverse stressors to induce T7SS activity which manifests through the antagonism of neighboring non-kin bystander bacterial cells.

scholarly journals Pseudomonas aeruginosa Resistance to Bacteriophages and Its Prevention by Strategic Therapeutic Cocktail Formulation

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 145
Author(s):  
Andrew Vaitekenas ◽  
Anna S. Tai ◽  
Joshua P. Ramsay ◽  
Stephen M. Stick ◽  
Anthony Kicic
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Treatment Options ◽  
Rapid Evolution ◽  
Resistance Mechanisms ◽  
Phage Resistance ◽  
Strategic Development ◽  
Promising Alternative ◽  
Narrow Host Range

Antimicrobial resistance poses a significant threat to modern healthcare as it limits treatment options for bacterial infections, particularly impacting those with chronic conditions such as cystic fibrosis (CF). Viscous mucus accumulation in the lungs of individuals genetically predisposed to CF leads to recurrent bacterial infections, necessitating prolonged antimicrobial chemotherapy. Pseudomonas aeruginosa infections are the predominant driver of CF lung disease, and airway isolates are frequently resistant to multiple antimicrobials. Bacteriophages, or phages, are viruses that specifically infect bacteria and are a promising alternative to antimicrobials for CF P. aeruginosa infections. However, the narrow host range of P. aeruginosa-targeting phages and the rapid evolution of phage resistance could limit the clinical efficacy of phage therapy. A promising approach to overcome these issues is the strategic development of mixtures of phages (cocktails). The aim is to combine phages with broad host ranges and target multiple distinct bacterial receptors to prevent the evolution of phage resistance. However, further research is required to identify and characterize phage resistance mechanisms in CF-derived P. aeruginosa, which differ from their non-CF counterparts. In this review, we consider the mechanisms of P. aeruginosa phage resistance and how these could be overcome by an effective future phage therapy formulation.

scholarly journals A Localized Phage-Based Antimicrobial System: Effect of Alginate on Phage Desorption from β-TCP Ceramic Bone Substitutes

Antibiotics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 560
Author(s):  
Rached Ismail ◽  
Natalia D. Dorighello Carareto ◽  
Jean-Christophe Hornez ◽  
Franck Bouchart
Keyword(s):  
Bacterial Infections ◽  
Phage Therapy ◽  
Local Treatment ◽  
Bone Substitutes ◽  
Prosthetic Material ◽  
System Effect ◽  
Promising Alternative ◽  
Alternative Approaches ◽  
Resistant Strains ◽  
The Impact

Tricalcium phosphate (TCP) is a prosthetic material commonly used as a bone substitute to repair osteoarticular diseases and injuries. In this type of bone reconstruction surgery, antibiotics remain the common preventive and therapeutic treatment for bacterial infection. Nevertheless, the emergence of multi-resistant strains requires complimentary or alternative treatments. Today, one of the promising alternative approaches is phage therapy. Phages are bacterial viruses that have several advantages over chemotherapy, such as the specificity of bacterial strain, the absence of side effects, and a rapid response. In this work, we studied the impact of alginate hydrogels for overlaying λvir-phage-loaded β-TCP ceramic bone substitutes, delaying the phage desorption. The results show that the use of a 1% alginate–CaCl2 hydrogel overlapping the β-TCP ceramic pellets leads to higher initial phage concentration on the material and extends the released time of phages to two weeks when compared with control pellets. These alginate-coated biomaterials also generate faster bacterial lysis kinetics and could therefore be a good practical prosthetic device for bone and joint surgeries by allowing local treatment of bacterial infections with phage therapy for a longer period of time.

scholarly journals Pharmacodynamics of non-replicating viruses, bacteriocins and lysins

2006 ◽  
Vol 273 (1602) ◽  
pp. 2703-2712 ◽  
Author(s):  
James J Bull ◽  
Roland R Regoes
Keyword(s):  
Mathematical Models ◽  
Cancer Treatment ◽  
Single Molecule ◽  
Bacterial Infections ◽  
Therapeutic Agent ◽  
Phage Therapy ◽  
Therapeutic Agents ◽  
Chemotherapeutic Agents ◽  
Adsorption Rates ◽  
The Impact

The pharmacodynamics of antibiotics and many other chemotherapeutic agents is often governed by a ‘multi-hit’ kinetics, which requires the binding of several molecules of the therapeutic agent for the killing of their targets. In contrast, the pharmacodynamics of novel alternative therapeutic agents, such as phages and bacteriocins against bacterial infections or viruses engineered to target tumour cells, is governed by a ‘single-hit’ kinetics according to which the agent will kill once it is bound to its target. In addition to requiring only a single molecule for killing, these agents bind irreversibly to their targets. Here, we explore the pharmacodynamics of such ‘irreversible, single-hit inhibitors’ using mathematical models. We focus on agents that do not replicate, i.e. in the case of phage therapy, we deal only with non-lytic phages and in the case of cancer treatment, we restrict our analysis to replication of incompetent viruses. We study the impact of adsorption on dead cells, heterogeneity in adsorption rates and spatial compartmentalization.

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