Specific determination of E. coli B using bacteriophage T4, nanofilters, and ATP assay
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Lytic cycle
Characterization of N4-like Pseudomonas Phage vB_Pae-PA14 Isolated from Seawater Sampled in Thailand
Bacteriophage, a predator virus of bacteria, is an abundant biological entity in the biosphere. With ultimate applications in medicine and biotechnology, new phages are extensively being isolated and characterized. The objective of the present study was to characterize lytic bacteriophage vB_Pae-PA14 infecting Pseudomonas aeruginosa ATCC 27853 that was isolated from seawater in Thailand. vB_Pae-PA14 was subjected to whole genome phylogenetic analysis, host range test, biofilm test and characterization. Results showed that the phage belonged to a group of N4-like viruses, could infect P. aeruginosa isolates including carbapenem-resistant P. aeruginosa. The burst size of vB_Pae-PA14 was 86 plaque-forming unit/infected cells. Also, the phage showed a greater ability to control planktonic P. aeruginosa cells than the biofilm cells. Phage could withstand physical stresses especially the high salt concentration. In brief, lytic bacteriophage vB_Pae-PA14 infecting P. aeruginosa was isolated and characterized, which might be useful in further bacteriophage lytic applications.
Lytic cycle
Phage therapy
Myoviridae
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The appearance of lytic bacteriophage against newly introduced starter strains used during commercial cheese manufacture occurs rapidly, and their origin is not well understood. In this study, members of the group N streptococci were examined for the presence of bacteriophage restriction and modification systems. Two streptococcal phages from Streptococcus cremoris TR and Streptococcus lactis C2 (phage designations tr and c2) showed restricted lytic development on S. cremoris 799 and KH, respectively. Efficiency of plaquing was 1.9 × 10 −7 for tr plaqued on 799 and 2.1 × 10 −7 for c2 plaqued on KH. After passage through the restrictive hosts, these phages demonstrated high lytic ability for formerly restrictive hosts. Stress of the restrictive host strains at temperatures of 40 to 50°C resulted in a significant increase in the efficiency of plaquing of restricted bacteriophages. Elevated temperatures are encountered during commercial cheese manufacture. The results suggested that the temporary loss of host restriction activity with the resulting modification of nonspecific bacteriophage may contribute directly to the appearance of lytic phage against new starter strains.
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Starter
Lysogenic cycle
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Vibrio parahaemolyticus is a foodborne pathogen that is frequently isolated from a variety of seafood. To control this pathogenic Vibrio spp., the implementation of bacteriophages in aquaculture and food industries have shown a promising alternative to antibiotics. In this study, six bacteriophages isolated from the seafood samples demonstrated a narrow host range specificity that infecting only the V. parahaemolyticus strains. Morphological analysis revealed that bacteriophages Vp33, Vp22, Vp21, and Vp02 belong to the Podoviridae family, while bacteriophages Vp08 and Vp11 were categorized into the Siphoviridae family. All bacteriophages were composed of DNA genome and showed distinctive restriction fragment length polymorphism. The optimal MOI for bacteriophage propagation was determined to be 0.001 to 1. One-step growth curve revealed that the latent period ranged from 10 to 20 min, and the burst size of bacteriophage was approximately 17 to 51 PFU/cell. The influence of temperature and pH levels on the stability of bacteriophages showed that all bacteriophages were optimally stable over a wide range of temperatures and pH levels. In vitro lytic activity of all bacteriophages demonstrated to have a significant effect against V. parahaemolyticus . Besides, the application of a bacteriophage cocktail instead of a single bacteriophage suspension was observed to have a better efficiency to control the growth of V . parahaemolyticus . Results from this study provided a basic understanding of the physiological and biological properties of the isolated bacteriophages before it can be readily used as a biocontrol agent against the growth of V. parahaemolyticus .
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Siphoviridae
Podoviridae
Myoviridae
Phage therapy
Coliphage
Lysogenic cycle
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Background and Objectives: Phage therapy has gained interest as an alternative treatment for methicillin-resistant Staph- ylococcus aureus (MRSA)infections. The purpose of this study was to isolate and characterize an effective bacteriophage against isolates of MRSA.
Materials and Methods: Bacteriophage was isolated from hospital sewage. Lytic activity and the titers of phage lysates were measured using spot test anddouble-layer plaque assay. The phage characterization was determined through trans- mission electron microscopy. Adsorption rate, host range and stabilitytests were investigated. The latent period and burst size were estimated from a one-step growth curve. The effect of bacteriophage against MRSA biofilms wasdetermined and Real-time PCR was used to assess the effects of the bacteriophage on the expression of the biofilm-associated genes.
Results: TEM resultsshowed that the phage resembled the Cystoviridae family. Its latent period was 30 min, corresponding to about 71/43 phage particles per infected cell. Thephage had a broad host range and it was most stable at 37°C and pH 7. It was sensitive to NaCl concentrations. The expressions of the biofilm-associated genes were significantly reduced in the presence of the phage.
Conclusion: The isolated phage was effective against MRSA strains and it can be an optional strategy of controlling biofilm development.
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Phage therapy
Myoviridae
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Resistance of bacteria to antimicrobial agents is of grave concern. Further research into the development of bacteriophage as therapeutic agents against bacterial infections may help alleviate this problem.To formulate bacteriophage into a range of semisolid and solid dosage forms and investigate the capacity of these preparations to kill bacteria under laboratory conditions.Bacteriophage suspensions were incorporated into dosage forms such as creams, ointments, pastes, pessaries and troches. These were applied to bacterial lawns in order to ascertain lytic capacity. Stability of these formulations containing phage was tested under various storage conditions.A range of creams and ointments were able to support phage lytic activity against Propionibacterium acnes. Assessment of the stability of these formulations showed that storage at 4 °C in light-protected containers resulted in optimal phage viability after 90 days. Pessaries/suppositories and troches were able to support phage lytic activity against Rhodococcus equi.We report here the in-vitro testing of semisolid and solid formulations of bacteriophage lytic against a range of bacteria known to contribute to infections of the epithelia. This study provides a basis for the future formulation of diverse phage against a range of bacteria that infect epithelial tissues.
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A system (pair) of bacteriophage pAl and the host bacterium Vibrio sp. At was isolated from seawater. The lysate of host cells infected with the phage showed a significant becteriolytic activity with wider lytic action spectra, more susceptibility at alkaline pH(=9) and higher stability of lytic activity in the lysate compared with other phage-induced lysins reported so far.
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Lysin
Lysogenic cycle
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Galleria mellonella
Lytic cycle
Phage therapy
Hemolymph
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The ability of Acinetobacter baumannii to form biofilms and develop antibiotic resistance makes it difficult to control infections caused by this bacterium. In this study, we explored the potential of a lytic bacteriophage to disrupt A. baumannii biofilms.The potential of the lytic bacteriophage to disrupt A. baumannii biofilms was assessed by performing electron microscopy, live/dead bacterial staining, crystal violet staining and by determining adenosine triphosphate release.The bacteriophage inhibited the formation of and disrupted preformed A. baumannii biofilms. Results of disinfection assay showed that the lytic bacteriophage lysed A. baumannii cells suspended in blood or grown on metal surfaces.These results suggest the potential of the lytic bacteriophage to disrupt A. baumannii biofilms.
Lytic cycle
Acinetobacter baumannii
Crystal violet
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Lytic cycle
Lysin
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