Faculty Opinions recommendation of Using nanoparticle optics assay for direct observation of the function of antimicrobial agents in single live bacterial cells.

Shiga toxin-producing Escherichia coli are pathogenic bacteria able to form biofilms both on abiotic surfaces and on food, thus increasing risks for food consumers. Moreover, biofilms are difficult to remove and more resistant to antimicrobial agents compared to planktonic cells. Bacteriophages, natural predators of bacteria, can be used as an alternative to prevent biofilm formation or to remove pre-formed biofilm. In this work, four STEC able to produce biofilm were selected among 31 different strains and tested against single bacteriophages and two-phage cocktails. Results showed that our phages were able to reduce biofilm formation by 43.46% both when used as single phage preparation and as a cocktail formulation. Since one of the two cocktails had a slightly better performance, it was used to remove pre-existing biofilms. In this case, the phages were unable to destroy the biofilms and reduce the number of bacterial cells. Our data confirm that preventing biofilm formation in a food plant is better than trying to remove a preformed biofilm and the continuous presence of bacteriophages in the process environment could reduce the number of bacteria able to form biofilms and therefore improve the food safety.

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Effect of Essential Oils on the Inhibition of Biofilm and Quorum Sensing in Salmonella Enteritidis 13076 and Salmonella Typhimurium 14028

Antibiotics ◽

10.3390/antibiotics10101191 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1191

Author(s):

Yuliany Guillín ◽

Marlon Cáceres ◽

Rodrigo Torres ◽

Elena Stashenko ◽

Claudia Ortiz

Keyword(s):

Quorum Sensing ◽

Essential Oils ◽

Salmonella Enterica ◽

Salmonella Enteritidis ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Transcriptional Analysis ◽

Bacterial Cells ◽

Sem Images ◽

Biofilm Inhibition

The emergence of multidrug-resistant microorganisms represents a global challenge that has led to a search for new antimicrobial compounds. Essential oils (EOs) from medicinal aromatic plants are a potential alternative for conventional antibiotics. In this study, the antimicrobial and anti-biofilm potential of 15 EOs was evaluated on planktonic and biofilm-associated cells of Salmonella enterica serovar Enteritidis ATCC 13076 (S. enteritidis) and Salmonella enterica serovar Typhimurium ATCC 14028 (S. typhimurium). In total, 4 out of 15 EOs showed antimicrobial activity and 6 EOs showed anti-biofilm activity against both strains. The EO from the Lippia origanoides chemotype thymol-carvacrol II (LTC II) presented the lowest minimum inhibitory concentration (MIC50 = 0.37 mg mL−1) and minimum bactericidal concentration (MBC = 0.75 mg mL−1) values. This EO also presented the highest percentage of biofilm inhibition (>65%) on both microorganisms, which could be confirmed by scanning electron microscopy (SEM) images. Transcriptional analysis showed significant changes in the expression of the genes related to quorum sensing and the formation of the biofilm. EOs could inhibit the expression of genes involved in the quorum sensing mechanism (luxR, luxS, qseB, sdiA) and biofilm formation (csgA, csgB, csgD, flhD, fliZ, and motB), indicating their potential use as anti-biofilm antimicrobial agents. However, further studies are needed to elucidate the action mechanisms of essential oils on the bacterial cells under study.

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The strategy of editing and modification of the genomes of bacterial viruses

Bacteriology ◽

10.20953/2500-1027-2020-1-48-59 ◽

2020 ◽

Vol 5 (1) ◽

pp. 48-59

Author(s):

A.S. Schurova ◽

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V.A. Bannov ◽

A.V. Popova ◽

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...

Keyword(s):

Antimicrobial Agents ◽

Phage Genome ◽

Genetically Engineered ◽

Bacterial Cells ◽

Practical Application ◽

Bacterial Strains ◽

Recombinant Phage ◽

Research Problems ◽

Genomic Editing

In recent decades, a major problem for health systems around the world is the wide spread of bacterial pathogens that are resistant to various antimicrobial agents. A possible approach to solving this problem is the use of bacteriophages, viruses that specifically infect bacterial cells, as well as enzymes and proteins encoded in their genomes. The development of genomic editing technologies, including those based on CRISPR-Cas editing, makes it possible to create genetically engineered or recombinant phage particles with desired properties that are important for further practical application. In this review, we consider issues related to the characterization of bacteriophages as biological objects and as promising candidates for controlling the spread of antibioticresistant bacterial strains. We discuss modern approaches and strategies for modifying the phage genomes using various methods of genetic engineering and molecular biology to solve a variety of practical and research problems. Keywords: bacteriophages, phage genome editing, CRISPR-Cas system

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Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings

Nanomaterials ◽

10.3390/nano10061230 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1230 ◽

Cited By ~ 2

Author(s):

Paul Cătălin Balaure ◽

Alexandru Mihai Grumezescu

Keyword(s):

Life Cycle ◽

Molecular Mechanisms ◽

Antimicrobial Agents ◽

Current Knowledge ◽

Emergent Properties ◽

Bacterial Cells ◽

Life Cycle Stages ◽

Fouling Release ◽

Biofilm Development ◽

And Control

Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of “emergent properties”, meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both “fouling-resistant” and “fouling release” strategies are addressed as well as their synergic combination in a single unique nanoplatform.

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Effect of milk chocolate supplementation with lyophilised Lactobacillus cells on its attributes

Czech Journal of Food Sciences ◽

10.17221/217/2009-cjfs ◽

2010 ◽

Vol 28 (No. 5) ◽

pp. 392-406 ◽

Cited By ~ 19

Author(s):

D. Żyżelewicz ◽

E. Nebesny ◽

I. Motyl ◽

Z. Libudzisz

Keyword(s):

Ambient Temperature ◽

High Temperatures ◽

Functional Food ◽

Lactobacillus Casei ◽

Probiotic Bacteria ◽

Live Cells ◽

Bacterial Cells ◽

Bacterial Strains ◽

Milk Chocolate ◽

Live Bacterial Cells

Manufacturing of novel foodstuffs supplemented with live probiotic bacteria has recently been intensively investigated. The supplementation of confectionery with probiotics is troublesome since some unit technological processes are conducted at high temperatures and the products are usually stored at ambient temperature. Our group has developed a method of the production of milk chocolate, sweetened with either sucrose or isomalt and aspartame, containing 32, 36, or 40 g/100 g fat, and supplemented with live cells of probiotic bacterial strains: Lactobacillus casei and paracasei. This new milk chocolate displayed the same sensory properties as the reference, probiotic-free chocolate. The number of live bacterial cells was maintained at the functional level of 10<sup>6</sup> ÷ 10<sup>8</sup> cfu/g after keeping for 12 months irrespective of the temperature. The highest number of live probiotic bacteria survived in the chocolate kept at 4°C. Thus the product can be regarded as functional food.

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