ABSTRACT
The environmental bacterium, Pseudomonas putida, possesses a broad spectrum of metabolic pathways. This makes it highly promising for use in biotechnological production as a cell factory, as well as in bioremediation strategies to degrade various aromatic pollutants. For P. putida to flourish in its environment, it must withstand the continuous threats posed by bacteriophages. Interestingly, until now, only a handful of phages have been isolated for the commonly used laboratory strain, P. putida KT2440, and no phage defence mechanisms have been characterized. In this study, we present a new Collection of Environmental P. putida Phages from Estonia, or CEPEST. This collection comprises 67 double-stranded DNA phages, which belong to 22 phage species and 9 phage genera. Our findings reveal that most phages in the CEPEST collection are more infectious at lower temperatures, have a narrow host range, and require an intact lipopolysaccharide for P. putida infection. Furthermore, we show that cryptic prophages present in the P. putida chromosome provide strong protection against the infection of many phages. However, the chromosomal toxin-antitoxin systems do not play a role in the phage defence of P. putida. This research provides valuable insights into the interactions between P. putida and bacteriophages, which could have significant implications for biotechnological and environmental applications.
Subject(s)
Host Specificity , Pseudomonas putida , Pseudomonas putida/virology , Pseudomonas putida/genetics , Pseudomonas putida/metabolism , Prophages/genetics , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Estonia , Bacteriophages/genetics , Bacteriophages/isolation & purificationABSTRACT
The objective of this study was to investigate the effectiveness of a phage cocktail against Pseudomonas fluorescens group and its effect on the microbial, physical and chemical properties of raw milk during different storage conditions. A phage cocktail consisting of Pseudomonas fluorescens, Pseudomonas tolaasii, and Pseudomonas libanensis phages was prepared. As a result, reductions in fluorescent Pseudomonas counts of up to 3.44 log units for the storage at 4 °C and 2.38 log units for the storage at 25 °C were achieved. Following the phage application, it is found that there was no significant difference in the total mesophilic aerobic bacteria and Enterobacteriaceae counts. However, it was observed that the number of lactic acid bacteria was higher in phage-treated groups. The results also showed that pH values in the phage added groups were lower than the others and the highest titratable acidity was obtained only in the bacteria-inoculated group. As a future perspective, this study suggests that, while keeping the number of target microorganisms under control in the milk with the use of phages during storage, the microbiota and accordingly the quality parameters of the milk can be affected. This work contributes to the development of effective strategies for maintaining the quality and extending the shelf life of milk and dairy products.
Subject(s)
Milk , Pseudomonas Phages , Pseudomonas fluorescens , Milk/microbiology , Pseudomonas fluorescens/virology , Animals , Pseudomonas Phages/physiology , Pseudomonas Phages/isolation & purification , Food Microbiology , Hydrogen-Ion Concentration , Bacteriophages/physiology , Bacteriophages/isolation & purificationABSTRACT
Pseudomonas syringae is a gram-negative plant pathogen that infects plants such as tomato and poses a threat to global crop production. In this study, a novel lytic phage infecting P. syringae pv. tomato DC3000, named phage D6, was isolated and characterized from sediments in a karst cave. The latent period of phage D6 was found to be 60 min, with a burst size of 16 plaque-forming units per cell. Phage D6 was stable at temperatures between 4 and 40 °C but lost infectivity when heated to 70 °C. Its infectivity was unaffected at pH 6-10 but became inactivated at pH ≤ 5 or ≥ 12. The genome of phage D6 is a linear double-stranded DNA of 307,402 bp with a G + C content of 48.43%. There is a codon preference between phage D6 and its host, and the translation of phage D6 gene may not be entirely dependent on the tRNA library provided by the host. A total of 410 open reading frames (ORFs) and 14 tRNAs were predicted in its genome, with 92 ORFs encoding proteins with predicted functions. Phage D6 showed low genomic similarity to known phage genomes in the GenBank and Viral sequence databases. Genomic and phylogenetic analyses revealed that phage D6 is a novel phage. The tomato plants were first injected with phage D6, and subsequently with Pst DC3000, using the foliar spraying and root drenching inoculum approach. Results obtained after 14 days indicated that phage D6 inoculation decreased P. syringae-induced symptoms in tomato leaves and inhibited the pathogen's growth in the leaves. The amount of Pst DC3000 was reduced by 150- and 263-fold, respectively. In conclusion, the lytic phage D6 identified in this study belongs to a novel phage within the Caudoviricetes class and has potential for use in biological control of plant diseases.
Subject(s)
Genome, Viral , Phylogeny , Plant Diseases , Pseudomonas syringae , Solanum lycopersicum , Pseudomonas syringae/virology , Pseudomonas syringae/genetics , Pseudomonas syringae/pathogenicity , Genome, Viral/genetics , Solanum lycopersicum/virology , Solanum lycopersicum/microbiology , Plant Diseases/microbiology , Plant Diseases/virology , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/classification , Base Composition , Open Reading Frames , Whole Genome Sequencing , DNA, Viral/geneticsABSTRACT
Bacteriophages are viruses that specifically infect target bacteria. Recently, bacteriophages have been considered potential biological control agents for bacterial pathogens due to their host specificity. Pseudomonas syringae pv. actinidiae (Psa) is a reemerging pathogen that causes bacterial canker of kiwifruit (Actinidia sp.). The economic impact of this pest and the development of resistance to antibiotics and copper sprays in Psa and other pathovars have led to investigation of alternative management strategies. Phage therapy may be a useful alternative to conventional treatments for controlling Psa infections. Although the efficacy of bacteriophage φ6 was evaluated for the control of Psa, the characteristics of other DNA bacteriophages infecting Psa remain unclear. In this study, the PHB09 lytic bacteriophage specific to Psa was isolated from kiwifruit orchard soil. Extensive host range testing using Psa isolated from kiwifruit orchards and other Pseudomonas strains showed PHB09 has a narrow host range. It remained stable over a wide range of temperatures (4-50 °C) and pH values (pH 3-11) and maintained stability for 50 min under ultraviolet irradiation. Complete genome sequence analysis indicated PHB09 might belong to a new myovirus genus in Caudoviricetes. Its genome contains a total of 94,844 bp and 186 predicted genes associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. The isolation and identification of PHB09 enrich the research on Pseudomonas phages and provide a promising biocontrol agent against kiwifruit bacterial canker.
Subject(s)
Host Specificity , Podoviridae/isolation & purification , Pseudomonas Phages/isolation & purification , Pseudomonas syringae/virology , Virion/ultrastructure , Actinidia/microbiology , DNA, Viral/chemistry , DNA, Viral/genetics , Plant Diseases/microbiology , Podoviridae/genetics , Podoviridae/physiology , Podoviridae/ultrastructure , Pseudomonas Phages/genetics , Pseudomonas Phages/physiology , Pseudomonas Phages/ultrastructureABSTRACT
In recent years, the use of bacteriophages (or 'phages') against multidrug-resistant (MDR) bacteria including Pseudomonas aeruginosa has drawn considerable attention, globally. In this work, we report the isolation and detailed characterization of a highly lytic Pseudomonasphage DRL-P1 isolated from wastewater. Under TEM, DRL-P1 appeared as a member of the phage family Myoviridae. DRL-P1 featured rapid adsorption (~ 5 min), short-latency (~ 30 min), and large burst size (~ 100 PFU per infected cell). DRL-P1 can withstand a wide temperature range (4 °C to 40 °C) and pH (5.0 to 10.0) conditions. The 66,243 bp DRL-P1 genome (MN564818) encodes at least 93 ORFs, of which 36 were functionally annotated based on homology with similar phage proteins available in the databases. Comparative analyses of related genomes suggest an independent evolutionary history and discrete taxonomic position of DRL-P1 within genus Pbunavirus. No toxin or antibiotic resistance genes was identified. DRL-P1 is tolerant to lyophilization and encapsulation techniques and retained lytic activity even after 18 months of storage. We also demonstrated decontaminating potentials of DRL-P1 in vitro, on an artificially contaminated cover-slip model. To the best of our knowledge, this is the first Pbunavirus to be reported from India. Our study suggests DRL-P1 as a potential candidate for various applications.
Subject(s)
Myoviridae , Pseudomonas Phages , Pseudomonas aeruginosa/virology , Wastewater , DNA, Viral , Drug Resistance, Multiple, Bacterial/genetics , Genome, Viral , Myoviridae/classification , Myoviridae/isolation & purification , Myoviridae/physiology , Pseudomonas Phages/classification , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/physiology , Wastewater/microbiology , Wastewater/virologyABSTRACT
Bacteriophage control of harmful or pathogenic bacteria has aroused growing interest, largely due to the rise of antibiotic resistance. The objective of this study was to test phages as potential agents for the biocontrol of an opportunistic pathogen Pseudomonas aeruginosa in water. Two P. aeruginosa bacteriophages (vB_PaeM_V523 and vB_PaeM_V524) were isolated from wastewater and characterized physically and functionally. Genomic and morphological characterization showed that both were myoviruses within the Pbunavirus genus. Both had a similar latent period (50-55 min) and burst size (124-134 PFU/infected cell), whereas there was variation in the host range. In addition to these environmental phages, a commercial Pseudomonas phage, JG003 (DSM 19870), was also used in the biocontrol experiments. The biocontrol potential of the three phages in water was tested separately and together as a cocktail against two P. aeruginosa strains; PAO1 and the environmental strain 17V1507. With PAO1, all phages initially reduced the numbers of the bacterial host, with phage V523 being the most efficient (>2.4 log10 reduction). For the environmental P. aeruginosa strain (17V1507), only the phage JG003 caused a reduction (1.2 log10) compared to the control. The cocktail of three phages showed a slightly higher decrease in the level of the hosts compared to the use of individual phages. Although no synergistic effect was observed in the host reduction with the use of the phage cocktail, the cocktail-treated hosts did not appear to acquire resistance as rapidly as hosts treated with a single phage. The results of this study provide a significant step in the development of bacteriophage preparations for the control of pathogens and harmful microbes in water environments.
Subject(s)
Biological Control Agents , Pseudomonas Phages/physiology , Pseudomonas aeruginosa/virology , Water Microbiology , Water Purification/methods , Bacteriolysis , Genome, Viral , Genomics/methods , Host Specificity , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/ultrastructureABSTRACT
BACKGROUND: P. aeruginosa is the primary source of hospital-acquired infections. Unfortunately, antibiotic resistance is growing to precariously high levels, making the infections by this pathogen life-threatening and hard to cure. One possible alternative to antibiotics is to use phages. However, the isolation of phages suitable for phage therapy- be lytic, be efficient, and have a broad host range -against some target bacteria has proven difficult. To identify the best places to look for these phages against P. aeruginosa we screened hospital sewages, soils, and rivers in two cities. RESULTS: We isolated eighteen different phages, determined their host range, infection property, and plaque morphology. We found that the sewage and sewage-contaminated environments are the most reliable sources for the isolation of Pseudomonas phages. In addition, phages isolated from hospital sewage showed the highest efficiency in lysing the bacteria used for host range determination. In contrast, phages from the river had larger plaque size and lysed bacteria with higher levels of antibiotic resistance. CONCLUSIONS: Our findings provided additional support for the importance of sewage as the source of phage isolation.
Subject(s)
Pseudomonas Phages/physiology , Rivers/virology , Sewage/virology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/physiology , Environmental Microbiology , Host Specificity , Humans , Phage Therapy , Pseudomonas Infections/therapy , Pseudomonas Phages/isolation & purification , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/virologyABSTRACT
Antibiotic resistance causes around 700,000 deaths a year worldwide. Without immediate action, we are fast approaching a post-antibiotic era in which common infections can result in death. Pseudomonas aeruginosa is the leading cause of nosocomial infection and is also one of the three bacterial pathogens in the WHO list of priority bacteria for developing new antibiotics against. A viable alternative to antibiotics is to use phages, which are bacterial viruses. Yet, the isolation of phages that efficiently kill their target bacteria has proven difficult. Using a combination of phages and antibiotics might increase treatment efficacy and prevent the development of resistance against phages and/or antibiotics, as evidenced by previous studies. Here, in vitro populations of a Pseudomonas aeruginosa strain isolated from a burn patient were treated with a single phage, a mixture of two phages (used simultaneously and sequentially), and the combination of phages and antibiotics (at sub-minimum inhibitory concentration (MIC) and MIC levels). In addition, we tested the stability of these phages at different temperatures, pH values, and in two burn ointments. Our results show that the two-phages-one-antibiotic combination had the highest killing efficiency against the P. aeruginosa strain. The phages tested showed low stability at high temperatures, acidic pH values, and in the two ointments. This work provides additional support for the potential of using combinations of phage-antibiotic cocktails at sub-MIC levels for the treatment of multidrug-resistant P. aeruginosa infections.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Burns/drug therapy , Pseudomonas Infections/therapy , Pseudomonas Phages/physiology , Pseudomonas aeruginosa/virology , Burns/microbiology , Humans , Microbial Sensitivity Tests , Phage Therapy , Phylogeny , Pseudomonas Infections/microbiology , Pseudomonas Phages/classification , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/physiology , Rivers/virology , Sewage/virologyABSTRACT
In the era where antibiotic resistance is considered one of the major worldwide concerns, bacteriophages have emerged as a promising therapeutic approach to deal with this problem. Genetically engineered bacteriophages can enable enhanced anti-bacterial functionalities, but require cloning additional genes into the phage genomes, which might be challenging due to the DNA encapsulation capacity of a phage. To tackle this issue, we designed and assembled for the first time synthetic phages with smaller genomes by knocking out up to 48% of the genes encoding hypothetical proteins from the genome of the newly isolated Pseudomonas aeruginosa phage vB_PaeP_PE3. The antibacterial efficacy of the wild-type and the synthetic phages was assessed in vitro as well as in vivo using a Galleria mellonella infection model. Overall, both in vitro and in vivo studies revealed that the knock-outs made in phage genome do not impair the antibacterial properties of the synthetic phages, indicating that this could be a good strategy to clear space from phage genomes in order to enable the introduction of other genes of interest that can potentiate the future treatment of P. aeruginosa infections.
Subject(s)
Genome Size , Genome, Viral , Pseudomonas Phages/genetics , Pseudomonas aeruginosa/virology , Synthetic Biology , Anti-Bacterial Agents/pharmacology , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/ultrastructureABSTRACT
Bacteriophage 8P was isolated with a Pseudomonas stutzeri strain isolated from an oil reservoir as its host bacterium. The phage genome comprises 63,753 base pairs with a G+C content of 64.35. The phage encodes 63 predicted proteins, and 27 of them were functionally assigned. No tRNA genes were found. Comparative genomics analysis showed that 8P displayed some relatedness to F116-like phages (78% identity, 20% query coverage). The genome has very low sequence similarity to the other phage genomes in the GenBank database and Viral Sequence Database. Based on whole-genome analysis and transmission electron microscopy imaging, 8P is proposed to be a member of a new species in the genus Hollowayvirus, family Podoviridae.
Subject(s)
Bacteriophages/genetics , Bacteriophages/isolation & purification , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Pseudomonas stutzeri/virology , Base Composition/genetics , DNA, Viral/genetics , Genome, Viral/genetics , Genomics/methods , Host Specificity/genetics , Phylogeny , Podoviridae/genetics , Podoviridae/isolation & purification , Sequence Analysis, DNA/methodsABSTRACT
Phytopathogenic pseudomonads are widespread in the world and cause a wide range of plant diseases. In this work, we describe the Pseudomonas phage Pf-10, which is a part of the biopesticide "Multiphage" used for bacterial diseases of agricultural crops caused by Pseudomonas syringae. The Pf-10 chromosome is a dsDNA molecule with two direct terminal repeats (DTRs). The phage genomic DNA is 39,424 bp long with a GC-content of 56.5%. The Pf-10 phage uses a packaging mechanism based on T7-like short DTRs, and the length of each terminal repeat is 257 bp. Electron microscopic analysis has shown that phage Pf-10 has the podovirus morphotype. Phage Pf-10 is highly stable at pH values from 5 to 10 and temperatures from 4 to 60 °C and has a lytic activity against Pseudomonas strains. Phage Pf-10 is characterized by fast adsorption rate (80% of virions attach to the host cells in 10 min), but has a relatively small number of progeny (37 ± 8.5 phage particles per infected cell). According to the phylogenetic analysis, phage Pf-10 can be classified as a new phage species belonging to the genus Pifdecavirus, subfamily Studiervirinae, family Autographiviridae, order Caudovirales.
Subject(s)
Bacteriophages/physiology , Biological Control Agents , Crops, Agricultural , Plant Diseases/prevention & control , Pseudomonas Phages/physiology , Pseudomonas syringae/virology , Bacteriophages/classification , Bacteriophages/genetics , Bacteriophages/isolation & purification , Base Composition , Caudovirales/genetics , Crops, Agricultural/microbiology , DNA, Viral/genetics , Genome, Viral , Host Specificity , Phylogeny , Plant Diseases/microbiology , Podoviridae/genetics , Pseudomonas Phages/classification , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Siphoviridae/genetics , VirionABSTRACT
Bacterial diseases of the edible white button mushroom Agaricus bisporus caused by Pseudomonas species cause a reduction in crop yield, resulting in considerable economic loss. We examined bacterial pathogens of mushrooms and bacteriophages that target them to understand the disease and opportunities for control. The Pseudomonastolaasii genome encoded a single type III protein secretion system (T3SS), but contained the largest number of non-ribosomal peptide synthase (NRPS) genes, multimodular enzymes that can play a role in pathogenicity, including a putative tolaasin-producing gene cluster, a toxin causing blotch disease symptom. However, Pseudomonasagarici encoded the lowest number of NRPS and three putative T3SS while non-pathogenic Pseudomonas sp. NS1 had intermediate numbers. Potential bacteriophage resistance mechanisms were identified in all three strains, but only P. agarici NCPPB 2472 was observed to have a single Type I-F CRISPR/Cas system predicted to be involved in phage resistance. Three novel bacteriophages, NV1, ÏNV3, and NV6, were isolated from environmental samples. Bacteriophage NV1 and ÏNV3 had a narrow host range for specific mushroom pathogens, whereas phage NV6 was able to infect both mushroom pathogens. ÏNV3 and NV6 genomes were almost identical and differentiated within their T7-like tail fiber protein, indicating this is likely the major host specificity determinant. Our findings provide the foundations for future comparative analyses to study mushroom disease and phage resistance.
Subject(s)
Agaricales/metabolism , Genome, Viral , Pseudomonas Phages/genetics , Pseudomonas Phages/isolation & purification , Pseudomonas/isolation & purification , Agaricales/virology , Agaricus/metabolism , Agaricus/virology , Amino Acid Sequence , Culture Media/chemistry , DNA, Bacterial/genetics , DNA, Bacterial/isolation & purification , Genome, Bacterial , Multigene Family , Peptide Synthases/genetics , Peptide Synthases/metabolism , Pseudomonas/metabolism , Pseudomonas/virology , Pseudomonas Phages/metabolism , Sequence Analysis, DNA , Type III Secretion Systems/genetics , Type III Secretion Systems/metabolismABSTRACT
Pseudomonas phages PaGz-1 and PaZq-1, two new phages infecting Pseudomonas aeruginosa, were isolated from fresh water in Guangdong province, China. The genomes of these two phages consist of 93,975 bp and 94,315 bp and contain 175 and 172 open reading frames (ORFs), respectively. The genome sequences of PaGz-1 and PaZq-1 share 95.8% identity with a query coverage of 94%, suggesting that these two phages belong to two different species. Based on results of nucleotide sequence alignment, gene annotation, and phylogenetic analysis, we propose PaGz-1 and PaZq-1 as representative isolates of two species in the genus Pakpunavirus within the family Myoviridae.
Subject(s)
Genome, Viral , Myoviridae/genetics , Open Reading Frames , Phylogeny , Pseudomonas Phages/genetics , Pseudomonas aeruginosa/virology , Base Sequence , China , Fresh Water/microbiology , Gene Ontology , Molecular Sequence Annotation , Myoviridae/classification , Myoviridae/isolation & purification , Pseudomonas Phages/classification , Pseudomonas Phages/isolation & purification , Pseudomonas aeruginosa/isolation & purification , Sequence Alignment , Whole Genome SequencingABSTRACT
Bacteriophage PaBG is a jumbo Myoviridae phage isolated from water of Lake Baikal. This phage has limited diffusion ability and thermal stability and infects a narrow range of Pseudomonas aeruginosa strains. Therefore, it is hardly suitable for phage therapy applications. However, the analysis of the genome of PaBG presents a number of insights into the evolutionary history of this phage and jumbo phages in general. We suggest that PaBG represents an ancient group distantly related to all known classified families of phages.
Subject(s)
Pseudomonas Phages/isolation & purification , Pseudomonas aeruginosa/virology , Genome, Viral , Host Specificity , Phylogeny , Pseudomonas Phages/classification , Pseudomonas Phages/genetics , Pseudomonas Phages/physiology , Pseudomonas aeruginosa/physiologyABSTRACT
The GenBank database contains over 2580 complete genome sequences from bacteriophages. However, limited reports are available concerning phages can that lyse members of Pseudomonas syringae, although this is a widespread bacterial species that can infect almost 200 plant species. In the present study, we isolated and characterized a new Siphoviridae phage, named "Pseudomonas phage vB_PsyS_Phobos" (for brevity, referred to here as Phobos). To our knowledge, this is one of the first genome sequences reported for a phage with lytic activity against P. syringae pv. syringae. The genome of Phobos is dsDNA of 56,734 bp with a GC content of 63.3%, containing 65 ORFs. Genome analysis revealed that Phobos is a novel lytic phage with unique genomic features and low similarity to other phages, suggesting that Phobos represents a new phage genus. Genome sequencing did not reveal sequences with significant similarity to known virulence factors, antibiotic resistance genes, potential immunoreactive allergens, or lysogeny-related proteins, suggesting suggests that phage Phobos is strictly lytic. Therefore, Phobos may be suitable for formulation as a biocontrol agent against P. syringae pv. syringae.
Subject(s)
Pseudomonas Phages/genetics , Pseudomonas syringae/virology , Siphoviridae/genetics , Base Composition , DNA, Viral/genetics , Open Reading Frames , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/ultrastructure , Sequence Analysis, DNA , Siphoviridae/isolation & purification , Siphoviridae/ultrastructure , Whole Genome SequencingABSTRACT
Bleeding canker of horse chestnut trees is a bacterial disease, caused by the bacterium Pseudomonas syringae pv. aesculi, estimated to be present in ~ 50% of UK horse chestnut trees. Currently, the disease has no cure and tree removal can be a common method of reducing inoculum and preventing spread. One potential method of control could be achieved using naturally occurring bacteriophages infective to the causative bacterium. Bacteriophages were isolated from symptomatic and asymptomatic horse chestnut trees in three locations in the South East of England. The phages were found to be belonging to both the Myoviridae and Podoviridae families by RAPD PCR and transmission electron microscopy. Experimental coevolution was carried out to understand the dynamics of bacterial resistance and phage infection and to determine whether new infective phage genotypes would emerge. The phages exhibited different coevolution patterns with their bacterial hosts across time. This approach could be used to generate novel phages for use in biocontrol cocktails in an effort to reduce the potential emergence of bacterial resistance.
Subject(s)
Aesculus/microbiology , Pseudomonas Phages/classification , Pseudomonas syringae/virology , Host Specificity , Myoviridae/classification , Plant Diseases/microbiology , Plant Leaves/microbiology , Podoviridae/classification , Pseudomonas Phages/isolation & purification , Pseudomonas syringae/pathogenicity , United KingdomABSTRACT
Two morphologically different bacteriophages were isolated from the river and soil samples from various locations of Maharashtra, India against the phytopathogen Pseudomonas sp. that was recently reported to cause a new bacterial blight of pomegranate. Both the phages belonged to the order Caudovirales representing the families Siphoviridae (vB_Psp.S_PRɸL2) and Myoviridae (vB_Psp.M_SSɸL8). The multiplicity of infection ranged from 0.01 to 0.1, phage adsorption rate from 39% to 66%, latent period from 10 to 20â¯min with a burst size of 24-85 phage particles per infected host cell. The genome size of phages PRɸL2 and SSɸL8 was approximately 25.403â¯kb and 29.877â¯kb respectively. Restriction digestion pattern of phage genomic DNA was carried out for phage PRɸL2, Eco RI resulted in two bands and Hind III resulted in three bands while for phage SSɸL8, both Eco RI and Hind III each resulted in three bands. SDS-PAGE protein profile showed six bands for PRɸL2 and nine bands for SSɸL8 of different proteins. Phages showed high pH stability over a range of 4-9, temperature stability over a range of 4-50⯰C and UV radiation showed a reduction up to 89.36% for PRɸL2 and 96% for SSɸL8. In short, the present research work discusses for the first time in-detailed characterization of phages of a phytopathogen Pseudomonas sp. from Maharashtra, India, which can be further efficiently used for biological control of the causative agent of a new bacterial blight disease of pomegranate.
Subject(s)
Lythraceae/microbiology , Plant Diseases/microbiology , Pseudomonas Phages/classification , Pseudomonas Phages/isolation & purification , Pseudomonas/virology , Caudovirales/classification , Caudovirales/genetics , Caudovirales/isolation & purification , Caudovirales/ultrastructure , DNA, Viral/analysis , Host Specificity , Hydrogen-Ion Concentration , India , Microbial Viability , Myoviridae/classification , Myoviridae/genetics , Myoviridae/isolation & purification , Myoviridae/ultrastructure , Pseudomonas Phages/genetics , Pseudomonas Phages/ultrastructure , Siphoviridae/classification , Siphoviridae/genetics , Siphoviridae/isolation & purification , Siphoviridae/ultrastructure , Temperature , Ultraviolet Rays/adverse effects , Viral Proteins/analysisABSTRACT
BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen and one of the leading causes of nosocomial infections. Moreover, the species can cause severe infections in cystic fibrosis patients, in burnt victims and cause disease in domestic animals. The control of these infections is often difficult due to its vast repertoire of mechanisms for antibiotic resistance. Phage therapy investigation with P. aeruginosa bacteriophages has aimed mainly the control of human diseases. In the present work, we have isolated and characterized a new bacteriophage, named Pseudomonas phage BrSP1, and investigated its host range against 36 P. aeruginosa strains isolated from diseased animals and against P. aeruginosa ATCC strain 27853. RESULTS: We have isolated a Pseudomonas aeruginosa phage from sewage. We named this virus Pseudomonas phage BrSP1. Our electron microscopy analysis showed that phage BrSP1 had a long tail structure found in members of the order Caudovirales. "In vitro" biological assays demonstrated that phage BrSP1 was capable of maintaining the P. aeruginosa population at low levels for up to 12 h post-infection. However, bacterial growth resumed afterward and reached levels similar to non-treated samples at 24 h post-infection. Host range analysis showed that 51.4% of the bacterial strains investigated were susceptible to phage BrSP1 and efficiency of plating (EOP) investigation indicated that EOP values in the strains tested varied from 0.02 to 1.72. Analysis of the phage genome revealed that it was a double-stranded DNA virus with 66,189 bp, highly similar to the genomes of members of the genus Pbunavirus, a group of viruses also known as PB1-like viruses. CONCLUSION: The results of our "in vitro" bioassays and of our host range analysis suggested that Pseudomonas phage BrSP1 could be included in a phage cocktail to treat veterinary infections. Our EOP investigation confirmed that EOP values differ considerably among different bacterial strains. Comparisons of complete genome sequences indicated that phage BrSP1 is a novel species of the genus Pbunavirus. The complete genome of phage BrSP1 provides additional data that may help the broader understanding of pbunaviruses genome evolution.
Subject(s)
Animals, Domestic/microbiology , Pseudomonas Phages/physiology , Pseudomonas aeruginosa/growth & development , Sewage/virology , Whole Genome Sequencing/methods , Animals , DNA/genetics , DNA, Viral/genetics , Genome Size , Microscopy, Electron , Open Reading Frames , Pseudomonas Phages/isolation & purification , Pseudomonas Phages/ultrastructure , Pseudomonas aeruginosa/isolation & purification , Pseudomonas aeruginosa/virology , Species SpecificityABSTRACT
The sophisticated antibiotic resistance mechanism of Pseudomonas aeruginosa has urged the development of alternative antibacterial strategies. Phage therapy has been proven successful for the treatment of multidrug-resistant infections. In this study, we reported two virulent P. aeruginosa phages, vB_PaeM_SCUT-S1 (S1) and vB_PaeM_SCUT-S2 (S2), which were characterized at morphological, genomic, and proteomic levels. Phages S1 and S2 were assigned to the Myoviridae family. The genome sequencing showed that the genome size of Phage S1 was 66,046 bp and that of Phage S2 was 94,434 bp. The phylogenetic tree indicated that the two phages were distantly related to each other and were classified in the genera Pbunavirus and Pakpunavirus respectively. Thirty-one proteins were identified for each phage by mass spectrometry and were used to substantiate the function of the predicted coding genes. The two phages inhibited the growth of P. aeruginosa strain PAO1 at low multiplicity of infection levels and had good performance both on preventing biofilm formation and eradicating preformed biofilms. They were also stable over a wide range of temperature and pH values, supporting their potential use in the treatment of P. aeruginosa infections.
Subject(s)
Genome, Viral , Proteome/analysis , Pseudomonas Phages/growth & development , Pseudomonas Phages/isolation & purification , Pseudomonas aeruginosa/virology , Viral Proteins/analysis , Virion/ultrastructure , Genomics , Mass Spectrometry , Microscopy, Electron, Transmission , Myoviridae/chemistry , Myoviridae/growth & development , Myoviridae/isolation & purification , Myoviridae/ultrastructure , Phylogeny , Proteomics , Pseudomonas Phages/chemistry , Pseudomonas Phages/ultrastructure , Sequence HomologyABSTRACT
Cystic fibrosis (CF) is a hereditary disease due to mutations in the CFTR gene and causes mortality in humans mainly due to respiratory infections caused by Pseudomonas aeruginosa. In a previous work we used phage therapy, which is a treatment with a mix of phages, to actively counteract acute P. aeruginosa infections in mice and Galleria mellonella larvae. In this work we apply phage therapy to the treatment of P. aeruginosa PAO1 infections in a CF zebrafish model. The structure of the CFTR channel is evolutionary conserved between fish and mammals and cftr-loss-of-function zebrafish embryos show a phenotype that recapitulates the human disease, in particular with destruction of the pancreas. We show that phage therapy is able to decrease lethality, bacterial burden, and the pro-inflammatory response caused by PAO1 infection. In addition, phage administration relieves the constitutive inflammatory state of CF embryos. To our knowledge, this is the first time that phage therapy is used to cure P. aeruginosa infections in a CF animal model. We also find that the curative effect against PAO1 infections is improved by combining phages and antibiotic treatments, opening a useful therapeutic approach that could reduce antibiotic doses and time of administration.