Isolation and characterization of antagonistic bacteria against Vibrio harveyi from milkfish Chanos chanos

Vibrio species are the most dominant multidrug-resistant opportunistic bacterial pathogens in coastal aquaculture environments. There is an urgent need for biocontrol strategy to enhance commercially viable shrimp production. In the present study, eight strains of Bacillus were isolated and characterised from surface mucus of milk fish maintained in greenwater system and their antagonistic effects were evaluated against shrimp pathogenic bacteria Vibrio harveyi, by agar well diffusion and co-culture methods. Promising organisms were immobilised onto a matrix for preparation of bioaugmentor and again tested for antagonistic activity against V. harveyi.

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Isolation and Characterization of Two Lytic Bacteriophages Infecting a Multi-Drug Resistant Salmonella Typhimurium and Their Efficacy to Combat Salmonellosis in Ready-to-Use Foods

Microorganisms ◽

10.3390/microorganisms9020423 ◽

2021 ◽

Vol 9 (2) ◽

pp. 423

Author(s):

Ahmed Esmael ◽

Ehab Azab ◽

Adil A. Gobouri ◽

Mohamed A. Nasr-Eldin ◽

Mahmoud M. A. Moustafa ◽

...

Keyword(s):

Salmonella Typhimurium ◽

Multidrug Resistant ◽

Viable Count ◽

Food Storage ◽

Chicken Breast ◽

Whole Genome Analysis ◽

Isolation And Characterization ◽

Phage Cocktail ◽

Global Threat

Foodborne salmonellosis is a global threat to public health. In the current study, we describe the isolation and characterization of two broad-spectrum, lytic Salmonella phages: SPHG1 and SPHG3 infecting a multidrug-resistant Salmonella Typhimurium EG.SmT3. Electron microscopy and whole genome analysis identified SPHG1 as a Myovirus, while SPHG3 as a new member of the genus “Kuttervirus” within the family Ackermannviridae. SPHG1 and SPHG3 had a lysis time of 60 min. with burst sizes of 104 and 138 PFU/cell, respectively. The two phages were robust at variable temperatures and pH ranges that match the corresponding values of most of the food storage and processing conditions. A phage cocktail containing the two phages was stable in the tested food articles for up to 48 h. The application of the phage cocktail at MOIs of 1000 or 100 resulted in a significant reduction in the viable count of S. Typhimurium by 4.2 log10/sample in milk, water, and on chicken breast. Additionally, the phage cocktail showed a prospective ability to eradicate and reduce the biofilm that formed by S. Typhimurium EG.SmT3. A phage cocktail of SPHG1 and SPHG3 is considered as a promising candidate as a biocontrol agent against foodborne salmonellosis due to its broad host ranges, highly lytic activities, and the absence of any virulence or lysogeny-related genes in their genomes.

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Isolation and Characterization of Bacteriophage ZCSE6 against Salmonella spp.: Phage Application in Milk

Biologics ◽

10.3390/biologics1020010 ◽

2021 ◽

Vol 1 (2) ◽

pp. 164-176

Author(s):

Abdallah S. Abdelsattar ◽

Anan Safwat ◽

Rana Nofal ◽

Amera Elsayed ◽

Salsabil Makky ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Raw Milk ◽

Salmonella Spp ◽

Isolation And Characterization ◽

Food Borne ◽

Wide Range ◽

Almost All ◽

And Control ◽

Milk And Dairy Products

Food safety is very important in the food industry as most pathogenic bacteria can cause food-borne diseases and negatively affect public health. In the milk industry, contamination with Salmonella has always been a challenge, but the risks have dramatically increased as almost all bacteria now show resistance to a wide range of commercial antibiotics. This study aimed to isolate a bacteriophage to be used as a bactericidal agent against Salmonella in milk and dairy products. Here, phage ZCSE6 has been isolated from raw milk sample sand molecularly and chemically characterized. At different multiplicities of infection (MOIs) of 0.1, 0.01, and 0.001, the phage–Salmonella interaction was studied for 6 h at 37 °C and 24 h at 8 °C. In addition, ZCSE6 was tested against Salmonella contamination in milk to examine its lytic activity for 3 h at 37 °C. The results showed that ZCSE6 has a small genome size (<48.5 kbp) and belongs to the Siphovirus family. Phage ZCSE6 revealed a high thermal and pH stability at various conditions that mimic milk manufacturing and supply chain conditions. It also demonstrated a significant reduction in Salmonella concentration in media at various MOIs, with higher bacterial eradication at higher MOI. Moreover, it significantly reduced Salmonella growth (MOI 1) in milk, manifesting a 1000-fold decrease in bacteria concentration following 3 h incubation at 37 °C. The results highlighted the strong ability of ZCSE6 to kill Salmonella and control its growth in milk. Thus, ZCSE6 is recommended as a biocontrol agent in milk to limit bacterial growth and increase the milk shelf-life.

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Isolation and characterization of Trichoderma asperellum for antagonistic activity against different soil-borne plant pathogens

International Journal of Chemical Studies ◽

10.22271/chemi.2021.v9.i1ax.11783 ◽

2021 ◽

Vol 9 (1) ◽

pp. 3547-3551

Author(s):

Krishnadeo Thite ◽

MV Totawar ◽

Payal V Kose ◽

Sarika W More ◽

AV Zope

Keyword(s):

Plant Pathogens ◽

Antagonistic Activity ◽

Trichoderma Asperellum ◽

Isolation And Characterization

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Isolation and Characterization of Two Klebsiella pneumoniae Phages Encoding Divergent Depolymerases

International Journal of Molecular Sciences ◽

10.3390/ijms21093160 ◽

2020 ◽

Vol 21 (9) ◽

pp. 3160 ◽

Cited By ~ 1

Author(s):

Pilar Domingo-Calap ◽

Beatriz Beamud ◽

Lucas Mora-Quilis ◽

Fernando González-Candelas ◽

Rafael Sanjuán

Keyword(s):

Klebsiella Pneumoniae ◽

Multidrug Resistant ◽

Health Concern ◽

Resistant Bacteria ◽

Isolation And Characterization ◽

The Family ◽

Important Challenge ◽

Tail Spike ◽

Reference Strains

The emergence of multidrug-resistant bacteria is a major global health concern. The search for new therapies has brought bacteriophages into the spotlight, and new phages are being described as possible therapeutic agents. Among the bacteria that are most extensively resistant to current antibiotics is Klebsiella pneumoniae, whose hypervariable extracellular capsule makes treatment particularly difficult. Here, we describe two new K. pneumoniae phages, πVLC5 and πVLC6, isolated from environmental samples. These phages belong to the genus Drulisvirus within the family Podoviridae. Both phages encode a similar tail spike protein with putative depolymerase activity, which is shared among other related phages and probably determines their ability to specifically infect K. pneumoniae capsular types K22 and K37. In addition, we found that phage πVLC6 also infects capsular type K13 and is capable of striping the capsules of K. pneumoniae KL2 and KL3, although the phage was not infectious in these two strains. Genome sequence analysis suggested that the extended tropism of phage πVLC6 is conferred by a second, divergent depolymerase. Phage πVLC5 encodes yet another putative depolymerase, but we found no activity of this phage against capsular types other than K22 and K37, after testing a panel of 77 reference strains. Overall, our results confirm that most phages productively infected one or few Klebsiella capsular types. This constitutes an important challenge for clinical applications.

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Isolation and characterization of endophytic bacteria from mangrove Rhizophora mucronata Lam. and antibacterial activity test against some pathogenic bacteria

Journal of Physics Conference Series ◽

10.1088/1742-6596/1402/3/033038 ◽

2019 ◽

Vol 1402 ◽

pp. 033038

Author(s):

B I G Maulani ◽

D A C Rasmi ◽

L Zulkifli

Keyword(s):

Antibacterial Activity ◽

Endophytic Bacteria ◽

Pathogenic Bacteria ◽

Rhizophora Mucronata ◽

Isolation And Characterization ◽

Activity Test

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Physiological and molecular characterization of compost bacteria antagonistic to soil-borne plant pathogens

Canadian Journal of Microbiology ◽

10.1139/cjm-2016-0599 ◽

2017 ◽

Vol 63 (5) ◽

pp. 411-426 ◽

Cited By ~ 12

Author(s):

Rowida Mohamed ◽

Emma Groulx ◽

Stefanie Defilippi ◽

Tamara Erak ◽

James T. Tambong ◽

...

Keyword(s):

Plant Pathogens ◽

Antagonistic Activity ◽

Antagonistic Bacteria ◽

Antimicrobial Compounds ◽

Fusarium Sambucinum ◽

Inhibitory Compounds ◽

Antimicrobial Lipopeptides ◽

Chemical Pesticides ◽

Insight Into

Disease suppressive composts have the potential to mitigate the risks associated with chemical pesticides. One of the main characteristics responsible for the suppressive nature of composts is their microbiological populations. To gain insight into the determinants responsible for their suppressive effects, we assayed composts to (i) isolate and identify beneficial antagonistic bacteria, (ii) quantify their antifungal and anti-oomycetal activities, (iii) extract inhibitory compounds produced by the bacteria, and (iv) identify antimicrobial lipopeptides produced by these bacteria. The antagonistic bacteria belonged to the genera Arthrobacter, Pseudomonas, Bacillus, Brevibacillus, Paenibacillus, and Rummeliibacillus and had the ability to antagonise the growth of Fusarium sambucinum, Verticillium dahliae, and (or) Pythium sulcatum. These bacteria produced antimicrobial compounds that affected the mycelial growth and (or) conidial germination of the pathogens. Mass spectrometry analyses showed the presence of various antimicrobial lipopeptides in Bacillus and Bacillus-related spp. extracts, demonstrating that they are responsible, at least in part, for the antagonistic activity of the bacteria. Results from this work provide greater insight into some of the biological, biochemical, and physiological determinants of suppressiveness in composts involved in the control of plant pathogens.

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