scholarly journals Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Pushpinder Kaur Litt ◽  
Divya Jaroni
Keyword(s):  
Beef Cattle ◽  
Latent Period ◽  
Host Range ◽  
Cold Storage ◽  
Growth Parameters ◽  
Burst Size ◽  
Morphological Characteristics ◽  
Lytic Activity ◽  
E Coli ◽  
The Stability

Bacteriophages, recovered from beef cattle environment and specifically targetingEscherichia coliO157:H7, were examined for their physiological and morphological characteristics. Degree of bacterial lysis and host range of isolated bacteriophages was determined against 55 isolates ofE. coliO157:H7. Morphology of phages was examined under transmission electron microscope. Phage growth parameters, particularly rate of adsorption, rise period, latent period, and burst size were also determined. The stability of isolated phages was tested at acidic and alkaline pH, at high temperatures, and in cold storage. A total of 7 phages were isolated which showed lytic activity against 50 out of 55 isolates ofE. coliO157:H7. Based on the morphology, phages were classified into Myoviridae or Siphoviridae family. Phages had a rise period between 19 and 40 min, a short latent period between 12 and 30 min, and a large burst size (89–631 virions per infected cell), indicating high lytic activity. Phages remained stable for 24 h at a wide pH (1–11) and temperature range (40–60°C) and for 90 d in cold storage. Characterization of bacteriophages, with a diverse host range ofE. coliO157:H7, could aid in the development of effective biocontrol strategies for this pathogen in the food industry.

Identification and characterization of lytic bacteriophages specific to foodborne pathogenic Escherichia coli O157:H7

2020 ◽  
Vol 27 (1) ◽  
pp. 56-72
Author(s):  
Zeliha Yıldirim ◽  
Tuba Sakin ◽  
Mustafa Akçelik ◽  
Nefise Akçelik
Keyword(s):  
Escherichia Coli ◽  
Latent Period ◽  
Burst Size ◽  
Rapid Development ◽  
Protein Band ◽  
Lytic Activity ◽  
Host Cells ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Wide Ph Range

The objective of this study was to identify and characterize five different lytic bacteriophages specific to Escherichia coli O157:H7. vB_EcoM-P12, vB_EcoM-P13, vB_EcoM-P23, and vB_EcoM-P34 phages belonged to the Myoviridae family and vB_EcoS-P24 phage was in the Siphoviridae family. Their plaque sizes changed between 0.48 ± 0.03 and 0.90 ± 0.03 mm in diameter. stx1 and stx2 virulent gene regions were absent in the genome of five Eco-phages and their genome size was 33 kbp. The protein band profiles of the five phages were found to be different from each other. Their latent period, burst size, and burst time changed between 10–15 min, 72–144 PFU/cell and 20–35 min, respectively. Multiplicity of infection values and mutant frequency of the phages were among 0.1–0.001 and 1.14 × 10−7–3.69 × 10−8, respectively. The phages had strong lytic activity against their host bacteria ( E. coli NCTC 12900, ATCC 43888, and ATCC 35150) at 5–37 ℃ and adsorbed to their host cells by 92.7–97.5% in the first five minutes of incubation. These phages are thought to be good candidates as therapeutic and biocontrol agents against E. coli O157:H7 in the veterinary science and food industry due to short latent period, high burst size, rapid development in host cells, high lytic activity, high adsorption rate, stability over a wide pH range and high temperature, and absence of stx1 and stx2 genes.

INFLUENCE OF SELECTED HERBICIDES IN PHAGES OF SOME SOIL BACTERIA

1982 ◽  
Vol 62 (1) ◽  
pp. 217-220 ◽  
Author(s):  
E. B. ROSLYCKY
Keyword(s):  
Latent Period ◽  
Soil Bacteria ◽  
Rhizobium Meliloti ◽  
Burst Size ◽  
Lytic Activity ◽  
Agrobacterium Radiobacter ◽  
Host System ◽  
Average Burst Size ◽  
Homologous Antiserum ◽  
Particle Attachment

Various concentrations of paraquat, atrazine, simazine, linuron, diuron, and paraquat in combinations with each including simazine + diuron, and terbacil alone, did not inhibit lytic activity of four bacteriophages of Agrobacterium radiobacter, three bacteriophages of Rhizobium meliloti, three bacteriophages of R. trifolii, or two bacteriophages of Streptomyces chrysomallus. Generally, the herbicides had no effect on the neutralization of radiobacterphage PR-1001 with its homologous antiserum, the length of the latent period, the percent adsorption or the average burst size. In contrast, paraquat concentrations from 20 to 400 μg∙mL−1 gradually reduced the adsorption from 38 to 21% and the average burst size from 67 to 9 in the PR-1001:R-1001 phage: host system. The same concentrations, however, showed no effect on the particle attachment or the length of the latent period.

scholarly journals Complete Genome Sequence of vB_EcoP_SU7, a Podoviridae Coliphage with the Rare C3 Morphotype

2021 ◽  
Vol 9 (8) ◽  
pp. 1576
Author(s):  
Shazeeda Koonjan ◽  
Callum J. Cooper ◽  
Anders S. Nilsson
Keyword(s):  
Host Range ◽  
Burst Size ◽  
Phylogenetic Analyses ◽  
Treatment Plant ◽  
Latency Period ◽  
Enterotoxigenic Escherichia Coli ◽  
Therapeutic Success ◽  
Significant Similarity ◽  
Narrow Host Range ◽  
E Coli

Enterotoxigenic Escherichia coli (ETEC) strains are an important cause of bacterial diarrheal illness in humans and animals. Infections arising from ETEC could potentially be treated through the use of bacteriophage (phage) therapy, as phages encode for enzymes capable of bacterial cell lysis. vB_EcoP_SU7 was isolated from the Käppala wastewater treatment plant in Stockholm, Sweden, and propagated on an ETEC strain exhibiting the O:139 serovar. Transmission electron microscopy confirmed that vB_EcoP_SU7 belongs to the Podoviridae family and has the rare C3 morphotype of an elongated head. Bioinformatic analyses showed that the genome was 76,626 base pairs long and contained 35 genes with predicted functions. A total of 81 open reading frames encoding proteins with hypothetical function and two encoding proteins of no significant similarity were also found. A putative tRNA gene, which may aid in vB_EcoP_SU7’s translation, was also identified. Phylogenetic analyses showed that compared to other Podoviridae, vB_EcoP_SU7 is a rare Kuravirus and is closely related to E. coli phages with the uncommon C3 morphotype, such as ECBP2, EK010, vB_EcoP_EcoN5, and vB_EcoP_SU10. Phage vB_EcoP_SU7 has a narrow host range, infecting 11 out of the 137 E. coli strains tested, a latency period of 30 min, a burst size of 12 PFU/cell, and an adsorption rate of 8.78 × 10−9 mL/min five minutes post infection. With a limited host range and poor infection kinetics, it is unlikely that SU7 can be a standalone phage used for therapeutic purposes; rather, it must be used in combination with other phages for broad-spectrum therapeutic success.

scholarly journals Characterization of the Three New Kayviruses and Their Lytic Activity Against Multidrug-Resistant Staphylococcus aureus

2019 ◽  
Vol 7 (10) ◽  
pp. 471 ◽  
Author(s):  
Natalia Łubowska ◽  
Bartłomiej Grygorcewicz ◽  
Katarzyna Kosznik-Kwaśnicka ◽  
Agata Zauszkiewicz-Pawlak ◽  
Alicja Węgrzyn ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Burst Size ◽  
Genomic Analysis ◽  
Multidrug Resistant ◽  
Biological Properties ◽  
Lytic Activity ◽  
Broad Host Range ◽  
Transmission Electron ◽  
Short Latent Period

The development of antimicrobial resistance has become a global concern. One approach to overcome the problem of drug resistance is the application of bacteriophages. This study aimed at characterizing three phages isolated from sewage, which show lytic activity against clinical isolates of multidrug-resistant Staphylococcus aureus. Morphology, genetics and biological properties, including host range, adsorption rate, latent time, phage burst size and lysis profiles, were studied in all three phages. As analyzed by transmission electron microscopy (TEM), phages vB_SauM-A, vB_SauM-C, vB_SauM-D have a myovirion morphology. One of the tested phages, vB_SauM-A, has relatively rapid adsorption (86% in 17.5 min), short latent period (25 min) and extremely large burst size (~500 plaque-forming units (PFU) per infected cell). The genomic analysis revealed that vB_SauM-A, vB_SauM-C, vB_SauM-D possess large genomes (vB_SauM-A 139,031 bp, vB_SauM-C 140,086 bp, vB_SauM-D 139,088 bp) with low G+C content (~30.4%) and are very closely related to the phage K (95–97% similarity). The isolated bacteriophages demonstrate broad host range against MDR S. aureus strains, high lytic activity corresponding to strictly virulent life cycle, suggesting their potential to treat S. aureus infections.

Isolation and properties of a bacteriophage lytic for a wide range of pseudomonads

1971 ◽  
Vol 17 (5) ◽  
pp. 677-682 ◽  
Author(s):  
R. A. Kelln ◽  
R. A. J. Warren
Keyword(s):  
Latent Period ◽  
Pseudomonas Fluorescens ◽  
Host Range ◽  
Burst Size ◽  
Broad Host Range ◽  
Lytic Bacteriophage ◽  
Bacterial Strains ◽  
Short Tail ◽  
Wide Range ◽  
Different Strains

The lytic bacteriophage ø-S1 was isolated from sewage using a strain of Pseudomonas fluorescens as host. It had a hexagonal head 60 nm in diameter and a short tail 30 nm long. ø-S1 had a broad host range, lysing strains from 10 biotypes of Pseudomonads. Although the latent period was fairly constant for the bacterial strains tested, the burst size varied considerably. The rate of adsorption of the phage to different strains also varied considerably.

scholarly journals Life without Division: Physiology ofEscherichia coliFtsZ-Deprived Filaments

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Alicia Sánchez-Gorostiaga ◽  
Pilar Palacios ◽  
Rocío Martínez-Arteaga ◽  
Manuel Sánchez ◽  
Mercedes Casanova ◽  
...  
Keyword(s):  
Solid Medium ◽  
Membrane Integrity ◽  
Test Tube ◽  
Antimicrobial Compounds ◽  
Liquid Form ◽  
Altered Expression ◽  
E Coli ◽  
Ftsz Ring ◽  
Altered Expression Pattern ◽  
The Stability

ABSTRACTWhen deprived of FtsZ,Escherichia colicells (VIP205) grown in liquid form long nonseptated filaments due to their inability to assemble an FtsZ ring and their failure to recruit subsequent divisome components. These filaments fail to produce colonies on solid medium, in which synthesis of FtsZ is induced, upon being diluted by a factor greater than 4. However, once the initial FtsZ levels are recovered in liquid culture, they resume division, and their plating efficiency returns to normal. The potential septation sites generated in the FtsZ-deprived filaments are not annihilated, and once sufficient FtsZ is accumulated, they all become active and divide to produce cells of normal length. FtsZ-deprived cells accumulate defects in their physiology, including an abnormally high number of unsegregated nucleoids that may result from the misplacement of FtsK. Their membrane integrity becomes compromised and the amount of membrane proteins, such as FtsK and ZipA, increases. FtsZ-deprived cells also show an altered expression pattern, namely, transcription of several genes responding to DNA damage increases, whereas transcription of some ribosomal or global transcriptional regulators decreases. We propose that the changes caused by the depletion of FtsZ, besides stopping division, weaken the cell, diminishing its resiliency to minor challenges, such as dilution stress.IMPORTANCEOur results suggest a role for FtsZ, in addition to its already known effect in the constriction ofE. coli, in protecting the nondividing cells against minor stress. This protection can even be exerted when an inactive FtsZ is produced, but it is lost when the protein is altogether absent. These results have implications in fields like synthetic biology or antimicrobial discovery. The construction of synthetic divisomes in the test tube may need to preserve unsuspected roles, such as this newly found FtsZ property, to guarantee the stability of artificial containers. Whereas the effects on viability caused by inhibiting the activity of FtsZ may be partly overcome by filamentation, the absence of FtsZ is not tolerated byE. coli, an observation that may help in the design of effective antimicrobial compounds.

scholarly journals Biological and Genomic Characterization of a Novel Jumbo Bacteriophage, vB_VhaM_pir03 with Broad Host Lytic Activity against Vibrio harveyi

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1051
Author(s):  
Gerald N. Misol ◽  
Constantina Kokkari ◽  
Pantelis Katharios
Keyword(s):  
Phage Therapy ◽  
Vibrio Harveyi ◽  
Burst Size ◽  
Disease Outbreaks ◽  
Artemia Salina ◽  
Open Reading Frames ◽  
Lytic Activity ◽  
Economic Losses ◽  
Phylogenomic Analysis ◽  
Antibiotic Resistant

Vibrio harveyi is a Gram-negative marine bacterium that causes major disease outbreaks and economic losses in aquaculture. Phage therapy has been considered as a potential alternative to antibiotics however, candidate bacteriophages require comprehensive characterization for a safe and practical phage therapy. In this work, a lytic novel jumbo bacteriophage, vB_VhaM_pir03 belonging to the Myoviridae family was isolated and characterized against V. harveyi type strain DSM19623. It had broad host lytic activity against 31 antibiotic-resistant strains of V. harveyi, V. alginolyticus, V. campbellii and V. owensii. Adsorption time of vB_VhaM_pir03 was determined at 6 min while the latent-phase was at 40 min and burst-size at 75 pfu/mL. vB_VhaM_pir03 was able to lyse several host strains at multiplicity-of-infections (MOI) 0.1 to 10. The genome of vB_VhaM_pir03 consists of 286,284 base pairs with 334 predicted open reading frames (ORFs). No virulence, antibiotic resistance, integrase encoding genes and transducing potential were detected. Phylogenetic and phylogenomic analysis showed that vB_VhaM_pir03 is a novel bacteriophage displaying the highest similarity to another jumbo phage, vB_BONAISHI infecting Vibrio coralliilyticus. Experimental phage therapy trial using brine shrimp, Artemia salina infected with V. harveyi demonstrated that vB_VhaM_pir03 was able to significantly reduce mortality 24 h post infection when administered at MOI 0.1 which suggests that it can be an excellent candidate for phage therapy.

scholarly journals Bactericidal and virucidal efficacies of food additive grade calcium hydroxide under various concentrations, organic material conditions, exposure duration, and its stability

2019 ◽  
Vol 12 (9) ◽  
pp. 1383-1389
Author(s):  
Sakchai Ruenphet ◽  
Kornkamon Paditporn ◽  
Darsaniya Punyadarsaniya ◽  
Tippawan Jantafong ◽  
Kazuaki Takehara
Keyword(s):  
Calcium Hydroxide ◽  
Organic Material ◽  
Exposure Duration ◽  
Organic Materials ◽  
Exposure Period ◽  
Food Additive ◽  
E Coli ◽  
Dry Conditions ◽  
Material Conditions ◽  
The Stability

Aim: This study aimed to evaluate the bactericidal and virucidal activity of food additive grade calcium hydroxide (FdCa(OH)2) under various concentrations, organic material conditions, and exposure duration including its stability. Materials and Methods: The FdCa(OH)2 powder as well as the 0.17% and 3% solutions were evaluated for bacteria and virus inactivating efficacies against Salmonella infantis (SI), Escherichia coli, Newcastle disease virus (NDV), and avian influenza virus (AIV), in the absence or presence of organic materials. In addition, the stability of FdCa(OH)2, was also examined using wet-dry conditions and under sunlight. Results: The FdCa(OH)2 powder could inactivate both NDV and AIV in the absence and presence of organic materials within a 3 min exposure period. The bactericidal efficacy using solution form revealed that 0.17% and 3% of FdCa(OH)2 could inactivate SI in the absence and presence of organic materials within 3 min of exposure. However, 3% of FdCa(OH)2 inactivated E. coli both with and without organic materials within 3min, while 0.17% required 5 min to be efficacious. The virucidal efficacy also showed that 0.17% FdCa(OH)2 could inactivate NDV in the absence and presence of organic materials within 10 min and 30 min, respectively. However, AIV inactivation was achieved within 30 sec under all conditions. In addition, under wet and dry conditions, FdCa(OH)2 powder demonstrated high efficacy when re-suspended at least 16 times for NDV and 7 times for AIV. Simultaneously, the FdCa(OH)2 powder retained its efficacy under the sunlight during up to 4 months for NDV and at least 6 months for AIV. Conclusion: The present study indicates that FdCa(OH)2 powder and solutions could inactivate SI, E. coli, NDV, and AIV while retaining good stability under challenging environmental conditions. Finally, the FdCa(OH)2 is safe for consumers because it is of food additive grade and can be useful as an alternative disinfectant, especially for biosecurity enhancement on and around poultry farms.

scholarly journals Isolation, characterization and efficacy of lytic bacteriophages against pathogenic Escherichia coli from hospital liquid waste

2020 ◽  
Vol 21 (7) ◽  
Author(s):  
Rahmad Lingga ◽  
Sri Budiarti ◽  
Iman Rusmana ◽  
Aris Tri Wahyudi
Keyword(s):  
Escherichia Coli ◽  
Host Range ◽  
Liquid Waste ◽  
Resistant Bacteria ◽  
Lytic Bacteriophage ◽  
Hospital Wastewater ◽  
Electron Micrograph ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Phage Treatment

Abstract. Lingga R, Budiarti S, Rusmana I, Wahyu AT. 2020. Isolation, characterization and efficacy of lytic bacteriophages against pathogenic Escherichia coli from hospital liquid waste. Biodiversitas 21: 3234-3241. Escherichia coli is known as a pathogenic contaminant bacteria in hospital wastewater hazardous to humans and the environment. Concerns about the emergence of chlorine- and antibiotic-resistant bacteria increase the urgency to find an alternative strategy to control pathogenic bacteria in hospital wastewater. One of the alternatives is using lytic bacteriophage. This study aimed to isolate, characterize, and examine the efficacy of lytic bacteriophage against pathogenic Escherichia coli from hospital wastewater. It isolated, characterized (plaque morphology, host range, virion electron micrograph, and sensitivity to temperature, pH, and chlorine treatments), and tested the efficacy of lytic bacteriophages in controlling pathogenic E. coli isolated from hospital wastewater. Five phages were successfully obtained, all of which had clear plaques (lytic phage character). Based on host range assay, most of the phages could lyse all tested E. coli strains but not for other species. Electron micrograph photography revealed that the phages belonged to Myoviridae. The phages showed stability in high temperature, broad-ranged pH, and high concentrations of chlorine treatments. Assay on phages efficacy suggested that the phages are capable of significantly reducing the E. coli population both in sterilized and non-sterilized wastewater. The combination of phage treatment and chlorine was more effective than single phage treatment. The efficacy test revealed that phage application in wastewater had the best result seen from cocktail treatment and a combination of phage treatment and chlorine. These results suggested that the phage can be a potential candidate for disinfection purposes.

scholarly journals Avaliação da estabilidade de agregados e a vulnerabilidade à erosão ao longo de uma vertente no município de Araruna, região noroeste do Paraná-Brasil / Evaluation of aggregates stability and vulnerability to erosion along a shed in the municipality of Araruna, northwest region of Paraná-Brazil

2018 ◽  
Vol 28 (55) ◽  
pp. 845-862
Author(s):  
Fabiana Barros Medeiros ◽  
Francieli Sant'ana Marcatto ◽  
Hélio Silveira ◽  
MariaTeresa De Nóbrega
Keyword(s):  
Structural Analysis ◽  
Soil Cover ◽  
Morphological Characteristics ◽  
Soil Horizons ◽  
Water Flows ◽  
Sandstone Formation ◽  
The Stability ◽  
Northwest Region

Esta pesquisa tem como objetivo estudar a vulnerabilidade à erosão dos solos da zona de contato do arenito da Formação Caiuá com o basalto da Formação Serra Geral, no município de Araruna, Mesorregião Noroeste Paranaense, dando enfoque ao papel da estabilidade da estrutura atual dos solos, considerando-se as alterações produzidas pelas formas de uso e ocupação da área. A análise realizada também considerou as variações das características morfológicas dos solos em perfil e ao longo da litossequência (sistema pedológico), assim como os seus reflexos na geração de setores mais ou menos suscetíveis à erosão na vertente. Para o levantamento dos solos ao longo da vertente foram utilizados os procediments propostos pela Análise Estrutural da Cobertura Pedológica e a coleta de amostras para a determinação da granulometria e estabilidade de agregados. Os resultados indicaram a ação dos fluxos de água laterais e verticais, atuando na transformação dos horizontes dos solos ao longo da vertente e uma variação da estabilidade estrutural associada as características morfológicas dos solos e ao tipo de uso e manejo empregado. Os Argissolos apresentaram agregados pequenos e um gradiente textural entre o horizonte superficial e subsuperficial, lhe conferindo uma forte suscetibilidade a erosão. O Nitossolo não apresentou grande diferenciação no tamanho dos agregados, exceto no horizonte Bw, onde a redução no tamanho dos agregados se associaram a mudança morfológica da estrutura do solo.AbstractThis research aims to study the vulnerability to soil erosion of the contact zone of the sandstone Formation Caiuá with basalt of the Serra Geral Formation, in the municipality of Araruna, Paraná Northwest Region, giving focus to the role of the stability of the current structure of soils, considering the changes produced by the forms of use and occupation of the area. The analysis also considered variations of morphological characteristics of soils in profile and along the lithosactivity (pedological system), as well as your reflexes in the generation of sectors more or less susceptible to erosion in the shed. For the survey of the soils along the strand, the procedures proposed by the Structural Analysis of the Pedological Coverage and the collection of samples for the determination of the granulometry and stability of aggregates were used. The results indicated the action of the lateral and vertical water flows, acting on the transformation of the soil horizons along the slope and a variation of the structural stability associated with the morphological characteristics of the soils and the type of use and management used. The Argisols presented small aggregates and a textural gradient between the surface and subsurface horizon, giving it a strong susceptibility to erosion. The Nitossolo did not show great differentiation in the size of the aggregates, except in the Bw horizon, where the reduction in the size of the aggregates was associated to the morphological change of the soil structure.Keywords: structural analysis of the soil cover, stability of aggregates, susceptibility to erosion, pedological systems.

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