Ketamine used in the therapy of depressive disorders impacts protein profile, proliferation rate and phagocytosis resistance of enterococci

Abstract Background: Ketamine is known to cause rapid anti-depressive effect. Additionally, it has been also proved that at high concentrations ketamine inhibits bacterial growth. It is also widely known that even sub-inhibitory concentration of chemicals, as concentration of ketamine used in therapy of depression, may change bacterial properties, including their virulence. The knowledge about possible influence of ketamine on bacterial commensals seems to be essential, as the mechanism of ketamine’s action in depression is believed to result also from its’ anti-inflammatory activity. In the current study we aimed to evaluate the in vitro influence of ketamine on proliferation rate, phagocytosis resistance and toxicity of enterococci. Results: The studied enterococcal strains were isolated as etiological agents of infection and collected in the Department of Medical Microbiology, Medical University of Gdansk. To measure metabolic activity of Enterococcus faecalis 10µM of CFDA-SE was added to bacterial suspension. The number of bacterial cells and fluorescence of particles were determined using FACSVerse flow cytometer. Additionally, for the determination of phagocytosis resistance, THP-1 human monocytes cell line from ATCC was used. Suspension of monocytes which engulfed bacteria was then stained with propidium iodide to determine cells’ membrane permeability and to evaluate cytotoxicity of enterococci. The result of the study proved diverse influence of therapeutic concentration of ketamine on Enterococci. In 23.1% of strains both proliferation rate and metabolism activity were inhibited. This group of strains was more susceptible to phagocytosis and had lower cytotoxicity than in culture without ketamine. Different response of isolates to ketamine was also visible in changes of protein profile determined by MALDI TOF. Conclusions: The analysis of bacteria at early stage of growth curve demonstrate the bacterial diversity in response to ketamine and let us set the hypothesis that microbiome susceptibility to ketamine may be one of the elements which should be taken into consideration when planning the successful pharmacotherapy of depression.

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THE RATE OF BACTERICIDAL ACTION OF PENICILLIN IN VITRO AS A FUNCTION OF ITS CONCENTRATION, AND ITS PARADOXICALLY REDUCED ACTIVITY AT HIGH CONCENTRATIONS AGAINST CERTAIN ORGANISMS

Journal of Experimental Medicine ◽

10.1084/jem.88.1.99 ◽

1948 ◽

Vol 88 (1) ◽

pp. 99-131 ◽

Cited By ~ 191

Author(s):

Harry Eagle ◽

A. D. Musselman

Keyword(s):

Bacterial Species ◽

Fold Increase ◽

Bactericidal Effect ◽

Penicillin G ◽

Bacterial Suspension ◽

Maximal Effect ◽

Maximal Rate ◽

Effective Level ◽

High Concentrations

1. The concentrations of penicillin G which (a) reduced the net rate of multiplication, (b) exerted a net bactericidal effect, and (c) killed the organisms at a maximal rate, have been defined for a total of 41 strains of α- and ß-hemolytic streptococci, Staphylococcus aureus and Staphylococcus albus, Diplococcus pneumoniae, and the Reiter treponoma. 2. The concentration which killed the organisms at a maximal rate was 2 to 20 times the minimal effective level ("sensitivity" as ordinarily defined). With some organisms, even a 32,000-fold increase beyond this maximally effective level did not further increase the rate of its bactericidal effect. However, with approximately half the strains here studied (all 4 strains of group B ß-hemolytic streptococci, 4 of 5 group C strains, 5 of 7 strains of Streptococcus fecalis, 2 of 4 other α-hemolytic streptococci, and 4 of 9 strains of staphylococci), when the concentration of penicillin was increased beyond that optimal level, the rate at which the organisms died was paradoxically reduced rather than increased, so that the maximal effect was obtained only within a relatively narrow optimal zone. 3. There were marked differences between bacterial species, and occasionally between different strains of the same species, not only with respect to the effective concentrations of penicillin, but also with respect to the maximal rate at which they could be killed by the drug in any concentration. Although there was a rough correlation between these two factors, there were many exceptions; individual strains affected only by high concentrations of penicillin might nevertheless be killed rapidly, while strains sensitive to minute concentrations might be killed only slowly. 4. Within the same bacterial suspension, individual organisms varied only to a minor degree with respect to the effective concentrations of penicillin. They varied strikingly, however, in their resistance to penicillin as measured by the times required to kill varying proportions of the cells.

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Attachment of Salmonella to mammalian cells in vitro

Canadian Journal of Microbiology ◽

10.1139/m83-263 ◽

1983 ◽

Vol 29 (12) ◽

pp. 1731-1735 ◽

Cited By ~ 5

Author(s):

Clifford S. Mintz ◽

Dean O. Cliver ◽

R. H. Deibel

Keyword(s):

Cell Lines ◽

Mammalian Cells ◽

Culture Cell ◽

Intestinal Cell ◽

Tissue Culture Cell ◽

Bacterial Cells ◽

Intestinal Cell Line ◽

Hela Cell Lines ◽

High Concentrations

The attachment of Salmonella typhimurium strain PHL67342 to several mammalian tissue culture cell lines was investigated. Strain PHL67342 failed to attach in significant numbers to the Buffalo green monkey (BGM), swine testicular (ST), and HeLa cell lines. Significant attachment was observed with the Henle intestinal cell line. Log-phase cells of strain PHL67342 attached in greatest numbers to the Henle cells after 45 min of incubation at 37 °C. Attachment to the Henle cells was not affected by D-mannose or D-galactose, but was markedly inhibited by high concentrations of alpha-methyl-D-mannoside. Also, Salmonella lipopolysaccharide had no effect on the attachment of strain PHL67342 to the Henle cells. Fimbriae were not detected on the bacterial cells used in the adherence experiments. These results suggest that some bacterial factor(s) other than fimbriae and lipopolysaccharide mediate the attachment of strain PHL67342 to the Henle cells.

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Effects of Topically Applied Betulinic Acid and NVX-207 on Melanocytic Tumors in 18 Horses

Animals ◽

10.3390/ani11113250 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3250

Author(s):

Lisa A. Weber ◽

Julien Delarocque ◽

Karsten Feige ◽

Manfred Kietzmann ◽

Jutta Kalbitz ◽

...

Keyword(s):

Betulinic Acid ◽

Early Stage ◽

Statistical Significance ◽

Treatment Protocol ◽

Controlled Study ◽

Double Blind ◽

Current Form ◽

Melanocytic Tumors ◽

High Concentrations

The naturally occurring betulinic acid (BA) and its derivative NVX-207 induce apoptosis in equine melanoma cells in vitro. After topical application, high concentrations of the substances can be reached in healthy equine skin. With the aim to investigate the effect and safety of topically applied BA and NVX-207 in horses with melanocytic tumors, the longitudinal, prospective, randomized, double-blind, placebo-controlled study protocol included eighteen Lipizzaner mares with early-stage cutaneous melanoma assigned to three groups. Melanocytic lesions were topically treated either with a placebo, 1% BA or 1% NVX-207 twice a day for 91 days. Caliper measurements, clinical examinations and blood tests were performed to assess the effects and safety of the medication. The topical treatment was convenient and safe. The volumes of tumors treated with BA were significantly reduced over time as compared to tumors treated with the placebo from day 80 of the study. Although treatment with NVX-207 seemed to decrease tumor volume, these results did not reach statistical significance. The findings must be regarded as preliminary due to the limited group size and need to be replicated in a larger cohort with modified pharmaceutical test formulations. Accordingly, the treatment protocol cannot yet be recommended in its current form.

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In vivo capture of bacterial cells by remote guiding

10.1101/2021.08.06.455395 ◽

2021 ◽

Author(s):

Iaroslav A. Rybkin ◽

Sergey I. Pinyaev ◽

Olga A. Sindeeva ◽

Sergey V. German ◽

Maja Koblar ◽

...

Keyword(s):

Genetic Material ◽

Local Concentration ◽

Bacterial Cells ◽

Bacterial Strains ◽

Toxic Side Effect ◽

High Concentrations ◽

Strong Barrier ◽

Growth Distribution

Recently, it has been shown that several bacterial strains can be very efficient in cancer treatment since they possess many important properties such as self-targeting, ease of detection, sensing and toxicity against tumors. However, there are only a few relevant candidates for such an approach, as targeting and detection one of the biggest challenges as well as there are many limitations in the use of genetic approaches. Here, it is proposed the solution that enables surface modification of alive bacterial cells without interfering with their genetic material and potentially reduces their toxic side effect. By the electrostatic interaction fluorescently labeled polyelectrolytes (PEs) and magnetite nanoparticles (NPs) were deposited on the bacterial cell surface to control the cell growth, distribution and detection of bacteria. According to the results obtained in vivo, by the magnet entrapment of the modified bacteria the local concentration of the cells was increased more than 5 times, keeping the high concentrations even when the magnet is removed. Since the PEs create a strong barrier, in vitro it was shown that the division time of the cells can be regulated for better immune presentation.

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Morphological Variation of Five Cut Chrysanthemum Cultivars Induced by 5-Azacytidine Treatment

HortScience ◽

10.21273/hortsci14012-18 ◽

2019 ◽

Vol 54 (7) ◽

pp. 1208-1216 ◽

Cited By ~ 1

Author(s):

Dongru Kang ◽

Silan Dai ◽

Kang Gao ◽

Fan Zhang ◽

Hong Luo

Keyword(s):

Flowering Time ◽

Flower Development ◽

Early Stage ◽

Growth Curves ◽

Phenotypic Data ◽

Flower Diameter ◽

Ray Florets ◽

High Concentrations ◽

Delayed Flowering

In this study, five cultivars of cut chrysanthemum Chrysanthemum ×morifolium Ramat., ‘Jinba’, ‘Yuuka’, ‘Fenguiren’, ‘Xueshen’, and ‘Huangjin’ were used to explore the functions of 5-azacytidine (5-azaC) on chrysanthemum growth and flower development. The results showed that 5-azaC had different effects on the growth of the five cultivars during in vitro culture. The final statistics showed that low concentrations promoted plant growth, whereas high concentrations inhibited growth; however, each cultivar had different growth curves, demonstrating that 5-azaC had no consistent inhibitory actions on growth. On the basis of the squaring time and flowering time statistics, we found that 5-azaC had a certain effect on the flowering time of all cut chrysanthemums, and all of these cultivars showed extremely early strains. Summer chrysanthemum (‘Yuuka’, ‘Fenguiren’, ‘Xueshen’, and ‘Huangjin’) treatments led to both early and delayed flowering. When the statistics were analyzed for different individuals, we found that the treatments shortened the squaring time in early-flowering plants. In ‘Jinba’, an autumn chrysanthemum, the treatment helped broken juvenile limitations and allowed plants to undergo photoperiod induction in the early stage. Additionally, we also determined the flower diameter differences in these treatments; ray florets from ‘Yuuka’ and ‘Huangjin’ trended to show tubular florets, and the location of tubular and ray florets were changed in ‘Xueshen’ capitulum. In conclusion, on the basis of flowering time in five early varieties of cut chrysanthemum, we propose that 5-azaC may regulate the methylation level of genes that control flower induction and flower development. These results provide phenotypic data and material for exploring the function of DNA methylation in regulating flowering.

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Eradication of Staphylococcus aureus Catheter-Related Biofilm Infections Using ML:8 and Citrox

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00910-16 ◽

2016 ◽

Vol 60 (10) ◽

pp. 5968-5975 ◽

Cited By ~ 8

Author(s):

S. Hogan ◽

M. Zapotoczna ◽

N. T. Stevens ◽

H. Humphreys ◽

J. P. O'Gara ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Therapeutic Potential ◽

Early Stage ◽

Content Type ◽

Catheter Lock ◽

High Concentrations ◽

Systemic Antibiotics

ABSTRACTStaphylococci are a leading cause of catheter-related infections (CRIs) due to biofilm formation. CRIs are typically managed by either device removal or systemic antibiotics, often in combination with catheter lock solutions (CLSs). CLSs provide high concentrations of the antimicrobial agent at the site of infection. However, the most effective CLSs against staphylococcal biofilm-associated infections have yet to be determined. The purpose of this study was to evaluate the efficacy and suitability of two newly described antimicrobial agents, ML:8 and Citrox, as CLSs againstStaphylococcus aureusbiofilms. ML:8 (1% [vol/vol]) and Citrox (1% [vol/vol]), containing caprylic acid and flavonoids, respectively, were used to treatS. aureusbiofilms grownin vitrousing newly described static and flow biofilm assays. Both agents reduced biofilm viability >97% after 24 h of treatment. Using a rat model of CRI, ML:8 was shown to inactivate early-stageS. aureusbiofilmsin vivo, while Citrox inactivated established, maturein vivobiofilms. Cytotoxicity and hemolytic activity of ML:8 and Citrox were equivalent to those of other commercially available CLSs. Neither ML:8 nor Citrox induced a cytokine response in human whole blood, and exposure ofS. aureusto either agent for 90 days was not associated with any increase in resistance. Taken together, these data reveal the therapeutic potential of these agents for the treatment ofS. aureuscatheter-related biofilm infections.

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Carbohydrate utilization of Erwinia amylovora in vitro

International Journal of Horticultural Science ◽

10.31421/ijhs/10/2/458 ◽

2004 ◽

Vol 10 (2) ◽

Cited By ~ 2

Author(s):

M. Hevesi ◽

A. Farkas ◽

A. Kása ◽

Zs. Orosz-Kovács

Keyword(s):

Sugar Content ◽

Fruit Trees ◽

Sugar Concentration ◽

Bacterial Cells ◽

Pome Fruit ◽

Carbohydrate Utilization ◽

Free Moisture ◽

High Concentrations

Nectar is a multi-component aqueous solution that promotes bacterial multiplication. The concentration of nectar in plant flowers is not stable since it is under the influence of environmental conditions, especially free moisture and relative humidity. Experiments were conducted with "artificial nectar" and directed along two lines: (1) determination of the optimal concentrations of carbohydrates for the growth of E. amylovora development (2) consumption of different carbohydrates besides basic sugars. Solutions of "artificial nectar" were prepared in different compositions by changing the dominance of basic sugars (fructose — glucose —sucrose) in proportions of 2:1:1, 1:2:1, 1:1:2 and between concentrations of 10-0.6% (diluted with Basal minimum broth) in order to determine optimal conditions for the development of E. amylovora. At a basic sugar concentration of 10% bacterial multiplication started and continued until I log degree (from 106 to 107 cfu/ml). At concentrations of 5% and 2,5 % cells developed with nearly the same kinetics (from 106 to 8x107 cfu/ml and from 106 to 9x107 cfu/ml, respectively). Multiplication was more pronounced and nearly the same at concentrations of 1.2 % and 0.6 % (from106 to 2x108 cfu/ml). At a basic sugar concentration 30% total sugars bacterial multiplication did not occur, while at 20 % it was negligible, not measurable photometrically. At minimal concentrations of F, G, S (between 1-0.1 %) bacterial cells were still able to multiply, producing organic acids from sugars. Our study showed that E. amylovora requires only a small amount of sugars (0.1%) for multiplication (acid production) while high concentrations inhibit multiplication. There was a negative correlation between sugar content and cell density. The optimal range of sugar concentration was at about 1%. Effect of "less frequent carbohydrates" to E. amylovora multiplication was also determined using the API 50 CH strip. We could provide information on utilization of 39 carbohydrates by the bacterium at different categories as follows: Not utilized-, Slowly and weakly utilized-, Slowly and completely utilized-, Quickly and completely utilized carbohydrates. We suppose that carbohydrates that belong to the latter two groups could play an important role as nectar components in promoting E. amylovora multiplication in the blossoms of pome fruit trees.

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The Comparison of Metronidazole, Clindamycin, and Amoxicillin Againts Streptococcus sanguinis

Journal of Indonesian Dental Association ◽

10.32793/jida.v1i1.293 ◽

2018 ◽

Vol 1 (1) ◽

Author(s):

Kevin Lim ◽

Armelia Sari Widyarman

Keyword(s):

Brain Heart Infusion ◽

Inhibition Zone ◽

Bacterial Suspension ◽

Bacterial Cells ◽

Viridans Streptococci ◽

Streptococcus Sanguinis ◽

Significant Difference ◽

Alveolar Osteitis

Introduction: Viridans streptococci group such as Streptococcus sanguinis (S. sanguinis), an anaerobic Gram-positive bacteria is a well-known for its involvement in dry socket (alveolar osteitis)-associated infection. Systemic amoxicillin, clindamycin and metronidazole have all been shown to be effective to inhibit this bacterium. However, there has been a lack of studies identifying which are the most effective amongst these antibiotics toward Streptococcus sanguinis. Objectives: The purpose of this study is to evaluate the effectiveness of metronidazole, clindamycin, and amoxicillin in inhibiting the growth of Streptococcus sanguinis in vitro. Methods: This effectiveness was done by using agar well diffusion methods. S. sanguinis ATCC 10556 were cultured in Brain Heart Infusion (BHI) broth at 37°C under anaerobic condition. After 48h, bacterial cells were harvested and counted using microplate reader (490 nm) to achieve optical density of 0.25-0.30 (107 CFU/mL). Subsequently, 100 μL of bacterial suspension was cultured on BHI agar and each antibiotic suspension was added into each agar well, incubated for 72h at 37°C. The inhibition zone diameters were measured with electronic caliper. All experiments were done in triplicate, and repeated two times in separated occasions. The obtained data were statistically analyzed using one-way ANOVA test. A p<0.05 was considered as significance. Result: The results showed that there was a significant difference in the effectiveness, clindamycin and amoxicillin in inhibiting the growth of Streptococcus sanguinis (p<0.05), compared to metronidazole. The inhibition zone diameter with mean±SD (mm) are 13.50±2.0, 34.67±2.3 and 32.67±1.7 for metronidazole, clindamycin and amoxicillin, respectively. Conclusion: Clindamycin and amoxicillin are more effective in inhibiting the growth of Streptococcus sanguinis compared to metronidazole in this study. However, future studies are needed to confirm this result in vivo.

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Establishment of novel in vitro culture system with the ability to reproduce oral biofilm formation on dental materials

Scientific Reports ◽

10.1038/s41598-021-00803-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tomoki Kohno ◽

Haruaki Kitagawa ◽

Ririko Tsuboi ◽

Yuma Nishimura ◽

Satoshi Imazato

Keyword(s):

Culture System ◽

Volume Fraction ◽

Sucrose Solution ◽

Glass Ionomer Cement ◽

Bacterial Suspension ◽

Bacterial Cells ◽

Oral Biofilm ◽

Restorative Materials

AbstractIntensive research has been conducted with the aim of developing dental restorative/prosthetic materials with antibacterial and anti-biofilm effects that contribute to controlling bacterial infection in the oral cavity. In situ evaluations were performed to assess the clinical efficacy of these materials by exposing them to oral environments. However, it is difficult to recruit many participants to collect sufficient amount of data for scientific analysis. This study aimed to assemble an original flow-cell type bioreactor equipped with two flow routes and assess its usefulness by evaluating the ability to reproduce in situ oral biofilms formed on restorative materials. A drop of bacterial suspension collected from human saliva and 0.2% sucrose solution was introduced into the assembled bioreactor while maintaining the incubation conditions. The bioreactor was able to mimic the number of bacterial cells, live/dead bacterial volume, and volume fraction of live bacteria in the in situ oral biofilm formed on the surface of restorative materials. The usefulness of the established culture system was further validated by a clear demonstration of the anti-biofilm effects of a glass-ionomer cement incorporating zinc-releasing glasses when evaluated by this system.

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Disruption of Membrane by Colistin Kills Uropathogenic Escherichia coli Persisters and Enhances Killing of Other Antibiotics

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01481-16 ◽

2016 ◽

Vol 60 (11) ◽

pp. 6867-6871 ◽

Cited By ~ 28

Author(s):

Peng Cui ◽

Hongxia Niu ◽

Wanliang Shi ◽

Shuo Zhang ◽

Hao Zhang ◽

...

Keyword(s):

Escherichia Coli ◽

Bacterial Infections ◽

Enhancement Effect ◽

Bacterial Cells ◽

Sulfa Drugs ◽

Content Type ◽

Bacterial Membranes ◽

Highly Active ◽

High Concentrations

ABSTRACTPersisters are small populations of quiescent bacterial cells that survive exposure to bactericidal antibiotics and are responsible for many persistent infections and posttreatment relapses. However, little is known about how to effectively kill persister bacteria. In the work presented here, we found that colistin, a membrane-active antibiotic, was highly active againstEscherichia colipersisters at high concentrations (25 or 50 μg/ml). At a clinically relevant lower concentration (10 μg/ml), colistin alone had no apparent effect onE. colipersisters. In combination with other drugs, this concentration of colistin enhanced the antipersister activity of gentamicin and ofloxacin but not that of ampicillin, nitrofurans, and sulfa drugsin vitro. The colistin enhancement effect was most likely due to increased uptake of the other antibiotics, as demonstrated by increased accumulation of fluorescence-labeled gentamicin. Interestingly, colistin significantly enhanced the activity of ofloxacin and nitrofurantoin but not that of gentamicin or sulfa drugs in the murine model of urinary tract infection. Our findings suggest that targeting bacterial membranes is a valuable approach to eradicating persisters and should have implications for more effective treatment of persistent bacterial infections.

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