scholarly journals Isolation and characterization Phage UPM1705 against multi-drug resistant K. pneumoniae 1705

2021 ◽  
pp. 19-25
Author(s):  
Omar Assafiri ◽  
Adelene Ai-Lian Song ◽  
Irwan Hanish ◽  
Geok Hun Tan ◽  
Khatijah Yusoff
Keyword(s):  
Burst Size ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Isolation And Characterization ◽  
Drug Resistant Bacteria ◽  
Transmission Electron ◽  
One Step ◽  
Almost All ◽  
Phage Growth ◽  
Bacteria Culture

The rise in in the number of drug-resistant bacteria that can resist almost all kinds of antibiotics is due to the overuse of these antibiotics (e.g., carbapenems). Thus, there is a need to find an alternative to antibiotic treatment such as the use of phages. In this study, phage UPM1705 was isolated from a polluted lake which can lyse its host Klebsiella pneumoniae ATCC BAA-1705. Based on morphological appearance from transmission electron microscopy, UPM1705 belongs to Caudovirales (Myoviridae). UPM1705 can reach a titer of 107 PFU/ml based on the double-layer method. It has a burst size of 298 PFU/bacteria cell and a latent period of 80 min, a rise period of 75 min, and adsorption time of 20 min based on a one-step growth curve assay using an MOI of 0.02. It was stable from 4°C to 80°C and retained its functionality at pH between 4 to 11, with pH of 7 being the optimum pH for the phage growth. The efficiency of UPM1705 was tested via a turbidity assay at MOI of 0.02, 0.2, and 2. UPM1705 was able to clear the turbidity of the host bacteria culture at all of these three MOIs. Thus, UPM1705 has the potential to be used for phage therapy.

scholarly journals vB-Ea-5: a lytic bacteriophage against multi-drug-resistant Enterobacter aerogenes

2021 ◽  
Author(s):  
Fatemeh Habibinava ◽  
Mohammad Reza Zolfaghari ◽  
Mohsen Zargar ◽  
Salehe Sabouri Shahrbabak ◽  
Mohammad Soleimani
Keyword(s):  
Burst Size ◽  
Gc Content ◽  
Enterobacter Aerogenes ◽  
Resistant Bacteria ◽  
Potential Candidate ◽  
Lytic Bacteriophage ◽  
Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Transmission Electron ◽  
Functional Classes

Background and Objectives: Multi-drug-resistant Enterobacter aerogenes is associated with various infectious diseases that cannot be easily treated by antibiotics. However, bacteriophages have potential therapeutic applications in the control of multi-drug-resistant bacteria. In this study, we aimed to isolate and characterize of a lytic bacteriophage that can lyse specifically the multi-drug-resistant (MDR) E. aerogenes. Materials and Methods: Lytic bacteriophage was isolated from Qaem hospital wastewater and characterized morphologically and genetically. Next-generation sequencing was used to complete genome analysis of the isolated bacteriophage. Results: Based on the transmission electron microscopy feature, the isolated bacteriophage (vB-Ea-5) belongs to the family Myoviridae. vB-Ea-5 had a latent period of 25 minutes, a burst size of 13 PFU/ml, and a burst time of 40 min. Genome sequencing revealed that vB-Ea-5 has a 135324 bp genome with 41.41% GC content. The vB-Ea-5 genome codes 212 ORFs 90 of which were categorized into several functional classes such as DNA replication and modification, transcriptional regulation, packaging, structural proteins, and a host lysis protein (Holin). No antibiotic resistance and toxin genes were detected in the genome. SDS-PAGE of vB-Ea-5 proteins exhibited three major and four minor bands with a molecular weight ranging from 18 to 50 kD. Conclusion: Our study suggests vB-Ea-5 as a potential candidate for phage therapy against MDR E. aerogenes infections.

scholarly journals Microwave assisted synthesis of negative-charge carbon dots with potential antibacterial activity against multi-drug resistant bacteria

RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 41202-41208
Author(s):  
Jung-Chang Kung ◽  
I-Ting Tseng ◽  
Chi-Sheng Chien ◽  
Sheng-Hui Lin ◽  
Chun-Chi Wang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Carbon Dots ◽  
Negative Charge ◽  
Resistant Bacteria ◽  
Microwave Assisted Synthesis ◽  
Drug Resistant ◽  
Antibacterial Ability ◽  
Microwave Assisted ◽  
Drug Resistant Bacteria ◽  
One Step

In this research, negative-charge carbon dots (CDs) were synthesized in one-step using a microwave and found to have potential antibacterial ability against multi-drug resistant bacteria.

scholarly journals The dual nature of bacteriophage: growth-dependent predation and generalised transduction of antimicrobial resistance

2021 ◽  
Author(s):  
Quentin J Leclerc ◽  
Jacob Wildfire ◽  
Arya Gupta ◽  
Jodi A Lindsay ◽  
Gwenan M Knight
Keyword(s):  
Antimicrobial Resistance ◽  
Stable Equilibrium ◽  
Burst Size ◽  
Antibiotic Resistance Gene ◽  
Interdisciplinary Approach ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Dual Nature ◽  
Drug Resistant Bacteria ◽  
Fundamental Shift

Bacteriophage ("phage") are both predators and evolutionary drivers for bacteria, notably contributing to the spread of antimicrobial resistance (AMR) genes by generalised transduction. Our current understanding of the dual nature of this relationship is limited. We used an interdisciplinary approach to quantify how these interacting dynamics can lead to the evolution of multi-drug resistant bacteria. We co-cultured two strains of Methicillin-resistant Staphylococcus aureus, each harbouring a different antibiotic resistance gene, with 80α generalized transducing phage. After a growth phase of 8h, bacteria and phage surprisingly coexisted at a stable equilibrium in our culture, the level of which was dependent on the starting concentration of phage. We detected double-resistant bacteria as early as 7h, indicating that transduction of AMR genes had occurred. We developed multiple mathematical models of the bacteria and phage relationship, and found that phage-bacteria dynamics were best captured by a model in which the phage burst size decreases as the bacteria population reaches stationary phase, and where phage predation is frequency-dependent. We estimated that one in every 108 new phage generated was a transducing phage carrying an AMR gene, and that double-resistant bacteria were always predominantly generated by transduction rather than by growth. Our results suggest a fundamental shift in how we understand and model phage-bacteria dynamics. Although rates of generalised transduction may seem insignificant, they are sufficient to consistently lead to the evolution of multi-drug resistant bacteria. Currently, the potential of phage to contribute to the growing burden of AMR is likely underestimated.

scholarly journals Phage-Antibiotic Synergy is Driven by a Unique Combination of Antibacterial Mechanism of Action and Stoichiometry

2020 ◽  
Author(s):  
Carmen Gu Liu ◽  
Sabrina I. Green ◽  
Lorna Min ◽  
Justin R. Clark ◽  
Keiko C. Salazar ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Therapeutic Option ◽  
Burst Size ◽  
Microtiter Plate ◽  
Resistant Bacteria ◽  
Dependent Manner ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Drug Resistant Bacteria ◽  
Drug Resistant Strains

AbstractThe continued rise in antibiotic resistance is precipitating a medical crisis. Bacteriophage (phage) has been hailed as one possible therapeutic option to augment the efficacy of antibiotics. However, only a handful of studies have addressed the synergistic relationship between phage and antibiotics. Here, we report a comprehensive analysis of phage-antibiotic interaction that evaluates synergism, additivism, and antagonism for all classes of antibiotics across clinically achievable stoichiometries. We combined an optically-based real-time microtiter plate readout with a matrix-like heatmap of treatment potencies to measure phage and antibiotic synergy (PAS), a process we term synography. Phage-antibiotic synography was performed against a pandemic drug-resistant clonal group of E. coli (ExPEC) with antibiotic levels blanketing the minimum inhibitor concentration (MIC) across seven orders of viral titers. Our results suggest that, under certain conditions, phages provide an adjuvating effect by lowering the MIC for drug-resistant strains. Furthermore, synergistic and antagonistic interactions are highly dependent on the mechanism of bacterial inhibition by the class of antibiotic paired to the phage, and when synergism is observed, it suppresses the emergence of resistant cells. Host conditions that simulate the infection environment, including serum and urine, suppress PAS in a bacterial growth-dependent manner. Lastly, phage burst size seems to be a significant driver of synergism. Collectively, this data suggests lytic phages can resuscitate an ineffective antibiotic for previously resistant bacteria, while also synergize with antibiotics in a class-dependent manner, processes that may be dampened by lower bacterial growth rates found in host environments.Significance StatementBacteriophage (phage) therapy is a promising approach to combat the rise of multi-drug resistant bacteria. Currently, the preferred clinical modality is to pair phage with an antibiotic, a practice thought to improve efficacy. However, antagonism between phage and antibiotics has been reported, the choice of phage and antibiotic is not often empirically determined, and the effect of the host factors on the effectiveness is unknown. Here, we interrogate phage-antibiotic interactions across antibiotics with different mechanisms of action. Our results suggest that phage can lower the working MIC for bacterial strains already resistant to the antibiotic, is dependent on the antibiotic class and stoichiometry of the pairing, and is dramatically influenced by the host microenvironment.

Isolation and characterization of two bacteriophages of a stem-nodulating Rhizobium strain from Sesbania rostrata

1984 ◽  
Vol 30 (5) ◽  
pp. 521-525 ◽  
Author(s):  
Philippe de Lajudie ◽  
Didier Bogusz
Keyword(s):  
Burst Size ◽  
Growth Cycle ◽  
Sesbania Rostrata ◽  
Isolation And Characterization ◽  
Rhizobium Strains ◽  
One Step ◽  
Average Burst Size ◽  
Step Growth ◽  
Phage Growth

Two rhizobiophages, RS1 and RS2, were isolated in Senegal from a soil sample and dry stem nodules of Sesbania rostrata, a tropical legume that is infected by two categories of Rhizobium strains: "stem strains," which nodulate both roots and stems (type strain, ORS571), and "root strains," which induce effective nodules only on roots. Both phages were found to have a host range restricted to ORS571; all root strains were found to be resistant. By electron microscopy, phage RS1 showed an hexagonal head 63 nm wide and a tail 87 nm long; phage RS2 revealed an hexagonal head 60 nm wide. Characterization of phage growth cycle by one-step growth experiments showed that the latent period was ca. 75 min for RS1 and ca. 4 h for RS2, that the rise period lasted ca. 2 h for both RS1 and RS2, and that the average burst size was ca. 100 for RS1 and 130 for RS2. Temperature denaturation occurred at 60–65 °C (RS1) and 45–50 °C (RS2). Serum neutralization tests revealed that the phages were not serologically related. In contrast to RS1, RS2 appeared to be temperate, since stable lysogens were isolated.

The size of extracellular vesicles secreted by different types of stem cells

2018 ◽  
pp. 38-42
Author(s):  
И.Б. Алчинова ◽  
М.В. Полякова ◽  
И.Н. Сабурина ◽  
М.Ю. Карганов
Keyword(s):  
Stem Cells ◽  
Extracellular Vesicles ◽  
Culture Media ◽  
Living Organism ◽  
Isolation And Characterization ◽  
Transmission Electron ◽  
Study Results ◽  
Multipotent Mesenchymal Stem Cells ◽  
Rat Adipose Tissue ◽  
Almost All

Механизм терапевтического действия мультипотентных мезенхимных стволовых клеток (ММСК) на облученный организм в последнее время вызывает повышенный интерес исследователей. В качестве активного участника паракринного механизма реализации этого эффекта предлагают рассматривать внеклеточные везикулы, секретируемые практически всеми клетками живого организма. Цель работы: выделить и охарактеризовать внеклеточные везикулы, продуцируемые стволовыми клетками различной природы. Материалы и методы. Суспензии внеклеточных везикул, выделенных по модифицированному протоколу дифференциального центрифугирования из культуральных жидкостей от культур ММСК костного мозга человека 2-го пассажа и ММСК жировой ткани крысы 4-го пассажа, были проанализированы методом просвечивающей электронной микроскопии и методом анализа траекторий наночастиц. Результаты. Исследование показало наличие в обоих образцах микрочастиц размерами до и около 100 нм, однако процентное содержание частиц разных размеров в суспензии различалось для двух анализируемых типов клеток. Заключение. Полученные результаты могут свидетельствовать о специфике секреции, обусловленной клеточным типом. A mechanism of the therapeutic effect of multipotent mesenchymal stem cells (MMSC) on irradiated body has recently arisen much interest of researchers. Extracellular vesicles (EVs) secreted by almost all cells of a living organism were suggested to actively contribute to the paracrine mechanism of this effect. The aim of the study was isolation and characterization of extracellular vesicles produced by various types of stem cells. Materials and methods. Suspensions of EVs were isolated from culture media of passage 2 human bone marrow-derived MMSC and passage 4 rat adipose tissue-derived MMSC using a modified protocol of differential centrifugation and then studied using transmission electron microscopy and nanoparticle tracking analysis. Results. The study showed the presence of microparticles with a size of >100 nm in the examined samples. However, the percent content of particles with different sizes in the suspension was different in two analyzed types of cell culture. Conclusion. The study results might reflect a specificity of secretion determined by the cell type.

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