scholarly journals Cationic, anionic and neutral dyes: effects of photosensitizing properties and experimental conditions on the photodynamic inactivation of pathogenic bacteria

2013 ◽  
Vol 11 (4) ◽  
pp. 590-599 ◽  
Author(s):  
Sonia Sabbahi ◽  
Layla Ben Ayed ◽  
Abdellatif Boudabbous
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Irradiation Time ◽  
Chemical Properties ◽  
Neutral Red ◽  
Viable Count ◽  
Photodynamic Inactivation ◽  
Experimental Conditions ◽  
Significant Difference

The aim of this study was to evaluate the photobactericidal effect of four photosensitizers (PSs) with different structural and physico-photochemical properties, namely mesotetracationic porphyrin (T4MPyP), dianionic rose Bengal (RB), monocationic methylene blue (MB) and neutral red (NR). Their photokilling activity was tested in vitro on pathogenic bacteria such as Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) suspended in nutrient broth (NB) and in phosphate buffered saline (PBS) through following their influence on the PSs antimicrobial efficacy. Photodynamic inactivation (PDI) experiments were performed using visible light (L) and different PSs concentrations (20–70 μM). The ability of these PSs to mediate bacterial photodynamic inactivation was investigated as a function of type of PS and its concentrations, spectral and physico-chemical properties, bacterial strain, irradiation time and suspending medium. Indeed, they showed antibacterial effects against S. aureus and P. aeruginosa with significant difference in potency. Staphylococcus aureus suspended in NB showed 0.92 log units reduction in viable count in the presence of T4MPyP at 20 μM. Changing the suspending medium from NB to PBS, S. aureus was successfully photoinactivated by T4MPyP (20 μM) when suspended in PBS at least time exposure (10 and 30 min), followed by MB and RB.

scholarly journals Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Shen ◽  
Qingfeng Liang ◽  
Guanyu Su ◽  
Yang Zhang ◽  
Zhiqun Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Uv Light ◽  
Irradiation Time ◽  
Survival Rates ◽  
Experimental Conditions ◽  
Light Power ◽  
Bacteria Growth ◽  
Inhibition Effect ◽  
Staphylococcus Epidermis

In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus, Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

scholarly journals In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms

2006 ◽  
Vol 55 (10) ◽  
pp. 1375-1380 ◽  
Author(s):  
Aaron Brady ◽  
Ryan Loughlin ◽  
Deirdre Gilpin ◽  
Paddy Kearney ◽  
Michael Tunney
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Viable Count ◽  
Tea Tree Oil ◽  
Coagulase Negative Staphylococci ◽  
Tea Tree ◽  
Skin Flora ◽  
Significant Difference ◽  
Time Kill

The susceptibility of Staphylococcus aureus [meticillin-resistant (MRSA) and meticillin-sensitive (MSSA)] and coagulase-negative staphylococci (CoNS), which respectively form part of the transient and commensal skin flora, to tea-tree oil (TTO) was compared using broth microdilution and quantitative in vitro time–kill test methods. MRSA and MSSA isolates were significantly less susceptible than CoNS isolates, as measured by both MIC and minimum bactericidal concentration. A significant decrease in the mean viable count of all isolates in comparison with the control was seen at each time interval in time–kill assays. However, the only significant difference in the overall mean log10 reduction in viable count between the groups of isolates was between CoNS and MSSA at 3 h, with CoNS isolates demonstrating a significantly lower mean reduction. To provide a better simulation of in vivo conditions on the skin, where bacteria are reported to grow as microcolonies encased in glycocalyx, the bactericidal activity of TTO against isolates grown as biofilms was also compared. Biofilms formed by MSSA and MRSA isolates were completely eradicated following exposure to 5 % TTO for 1 h. In contrast, of the biofilms formed by the nine CoNS isolates tested, only five were completely killed, although a reduction in viable count was apparent for the other four isolates. These results suggest that TTO exerts a greater bactericidal activity against biofilm-grown MRSA and MSSA isolates than against some biofilm-grown CoNS isolates.

scholarly journals DAYA HAMBAT DAUN MANUKAN (Rhinacanthus nasutus (L) Kurz) TERHADAP BAKTERI STAPHYLOCOCCUS AUREUS SECARA IN VITRO

2019 ◽  
Vol 6 (2) ◽  
pp. 106-113
Author(s):  
Sunarti Sunarti ◽  
Debora Paninsari
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Ethanol Extract ◽  
Average Diameter ◽  
Inhibition Zone ◽  
In Vitro Test ◽  
Extract Concentration ◽  
Significant Difference ◽  
Rhinacanthus Nasutus

The use of antimicrobial such as antibiotics  against infectious diseases with no control is quite common in Indonesia. This leads to increase morbidity and incidence of drug resistance. Staphylococcus aureus is a pathogenic bacteria, particularly infects the skin. The resistance it difficult to determine which antimicrobials were suitable for therapy. Manukan leaves have an active substance Rhinacanthin can be used as an anti-bacterial. The aim of this study was to determine the inhibition of ethanol extract of manukan leaves (Rhinacanthus nasutus (L) Kurz) against gram-positive bacteria (Staphylococcus aureus) in vitro with the extract concentration of 15,  30, and 60% as a control. This study was a true experiment through the in vitro test with the Kirby Bauer method. The results showed that the average diameter of the inhibition zone was at an extract concentration of 15, 30, and 60% are 9.97 mm, 10.95mm, and 13.18 mm. The Kruskal-Wallis test results showed a significant difference between the four treatment groups (p= 0.010). The Mann-Whitney test showed significant differences in the inhibition zone between control and  treatment at 15, 30 and 60% (p= 0.037). In conclusion leave ethanol extract of manukan has antimicrobial activitiy in inhibiting staphylococcus aureus.

scholarly journals Efficiency of Antimicrobial Photodynamic Therapy with Photodithazine® on MSSA and MRSA Strains

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 869
Author(s):  
Beatriz Müller Nunes Souza ◽  
Juliana Guerra Pinto ◽  
André Henrique Correia Pereira ◽  
Alejandro Guillermo Miñán ◽  
Juliana Ferreira-Strixino
Keyword(s):  
Staphylococcus Aureus ◽  
Photodynamic Therapy ◽  
Antimicrobial Photodynamic Therapy ◽  
Bacterial Inactivation ◽  
Bacterial Reduction ◽  
Complete Inactivation ◽  
Opportunistic Bacteria ◽  
Significant Difference ◽  
Mrsa Strains

Staphylococccus aureus is a ubiquitous and opportunistic bacteria associated with high mortality rates. Antimicrobial photodynamic therapy (aPDT) is based on the application of a light source and a photosensitizer that can interact with molecular oxygen, forming Reactive Oxygen Species (ROS) that result in bacterial inactivation. This study aimed to analyze, in vitro, the action of aPDT with Photodithazine® (PDZ) in methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains. The strains were incubated with PDZ at 25, 50, 75, and 100 mg/L for 15 min and irradiated with fluences of 25, 50, and 100 J/cm2. The internalization of PDZ was evaluated by confocal microscopy, the bacterial growth by counting the number of colony-forming units, as well as the bacterial metabolic activity post-aPDT and the production of ROS. In both strains, the photosensitizer was internalized; the production of ROS increased when the aPDT was applied; there was a bacterial reduction compared to the control at all the evaluated fluences and concentrations; and, in most parameters, it was obtained complete inactivation with significant difference (p < 0.05). The implementation of aPDT with PDZ in clinical strains of S. aureus has resulted in its complete inactivation, including the MRSA strains.

scholarly journals Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

2005 ◽  
Vol 187 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Lauren M. Mashburn ◽  
Amy M. Jett ◽  
Darrin R. Akins ◽  
Marvin Whiteley
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Iron Acquisition ◽  
Low Oxygen ◽  
Dialysis Membrane ◽  
Opportunistic Human Pathogen ◽  
The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

scholarly journals Lactic Acid Bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) in Yogurt Inhibit the Growth of Escherichia coli, Salmonella typhimurium, and Shigella sp. In Vitro

2021 ◽  
Vol 31 (4) ◽  
pp. 2
Author(s):  
IDSAP Peramiarti
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Pathogenic Bacteria ◽  
Test Method ◽  
P Value ◽  
E Coli ◽  
Significant Difference

Diarrhea is defecation with a frequency more often than usual (three times or more) a day (10 mL/kg/day) with a soft or liquid consistency, even in the form of water alone. Pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, and Shigella sp., play a role in many cases, to which antibiotics are prescribed as the first-line therapy. However, since antibiotic resistance cases are often found, preventive therapies are needed, such as consuming yogurt, which is produced through a fermentation process by lactic acid bacteria (LAB). This research aimed to determine the activity of lactic acid bacteria (Liactobacillus bulgaricus and Streptococcus thermophilus) in yogurt in inhibiting the growth of the pathogenic bacteria E. coli, S. typhimurium, and Shigella sp. The research applied in vitro with the liquid dilution test method and the true experimental design research method with post-test-only and control group design. The design was used to see the inhibitory effect of yogurt LAB on the growth of E. coli, S. typhimurium, and Shigell sp. to compare the effect of several different yogurt concentrations, namely 20%, 40%, 60%, and 80%. The results of the Least Significance Different analysis showed that there was a significant difference between yogurt with a concentration of 0% and that with various concentrations in inhibiting the growth of E. coli, S. typhimurium, and Shigella sp. with a p-value of &lt;0.05. Whereas, there was no significant difference in the various concentrations of yogurt in inhibiting the growth of the three kinds of bacteria with a p-value of &gt; 0.05.<p class="Default" align="center"> </p>

scholarly journals Antimicrobial Activity of Lemongrass Essential Oil (Cymbopogon flexuosus) and Its Active Component Citral Against Dual-Species Biofilms of Staphylococcus aureus and Candida Species

2020 ◽  
Vol 10 ◽  
Author(s):  
Shanjun Gao ◽  
Guangzhi Liu ◽  
Jianguo Li ◽  
Jing Chen ◽  
Lina Li ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Essential Oil ◽  
Pathogenic Bacteria ◽  
Expression Of Genes ◽  
Cymbopogon Flexuosus ◽  
Underlying Mechanisms ◽  
Bacteria And Fungi ◽  
Conventional Antibiotics ◽  
Lemongrass Essential Oil

Compared to mono-species biofilm, biofilms formed by cross-kingdom pathogens are more refractory to conventional antibiotics, thus complicating clinical treatment and causing significant morbidity. Lemongrass essential oil and its bioactive component citral were previously demonstrated to possess strong antimicrobial efficacy against pathogenic bacteria and fungi. However, their effects on polymicrobial biofilms remain to be determined. In this study, the efficacy of lemongrass (Cymbopogon flexuosus) essential oil and its bioactive part citral against dual-species biofilms formed by Staphylococcus aureus and Candida species was evaluated in vitro. Biofilm staining and viability test showed both lemongrass essential oil and citral were able to reduce biofilm biomass and cell viability of each species in the biofilm. Microscopic examinations showed these agents interfered with adhesive characteristics of each species and disrupted biofilm matrix through counteracting nucleic acids, proteins and carbohydrates in the biofilm. Moreover, transcriptional analyses indicated citral downregulated hyphal adhesins and virulent factors of Candida albicans, while also reducing expression of genes involved in quorum sensing, peptidoglycan and fatty acids biosynthesis of S. aureus. Taken together, our results demonstrate the potential of lemongrass essential oil and citral as promising agents against polymicrobial biofilms as well as the underlying mechanisms of their activity in this setting.

Characterization of Antibacterial Proanthocyanidins of Dalbergia monetaria, an Amazonian Medicinal Plant, by UHPLC-HRMS/MS

Planta Medica ◽  
2020 ◽  
Vol 86 (12) ◽  
pp. 858-866
Author(s):  
Patricia Homobono Brito de Moura ◽  
Amaryllis Almeida de Sousa ◽  
Andrea Porzel ◽  
Ludger A. Wessjohann ◽  
Ivana Correa Ramos Leal ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Neutral Loss ◽  
Antibacterial Activities ◽  
Quinone Methide ◽  
In Vitro Assays ◽  
Fragmentation Pattern ◽  
Bacterial Strains ◽  
Tract Infections

Abstract Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.

scholarly journals Synthesis and Cytotoxicity Studies of Wood-Based Cationic Cellulose Nanocrystals as Potential Immunomodulators

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1603
Author(s):  
Yusha Imtiaz ◽  
Beza Tuga ◽  
Christopher W. Smith ◽  
Alexander Rabideau ◽  
Long Nguyen ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Chemical Properties ◽  
Neutral Red ◽  
Cationic Polymers ◽  
Experimental Conditions ◽  
Physiological Processes ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Cytotoxicity Studies ◽  
Low Cytotoxicity

Polysaccharides have been shown to have immunomodulatory properties. Modulation of the immune system plays a crucial role in physiological processes as well as in the treatment and/or prevention of autoimmune and infectious diseases. Cellulose nanocrystals (CNCs) are derived from cellulose, the most abundant polysaccharide on the earth. CNCs are an emerging class of crystalline nanomaterials with exceptional physico-chemical properties for high-end applications and commercialization prospects. The aim of this study was to design, synthesize, and evaluate the cytotoxicity of a series of biocompatible, wood-based, cationic CNCs as potential immunomodulators. The anionic CNCs were rendered cationic by grafting with cationic polymers having pendant +NMe3 and +NH3 moieties. The success of the synthesis of the cationic CNCs was evidenced by Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, and elemental analysis. No modification in the nanocrystals rod-like shape was observed in transmission electron microscopy and atomic force microscopy analyses. Cytotoxicity studies using three different cell-based assays (MTT, Neutral Red, and LIVE/DEAD®) and three relevant mouse and human immune cells indicated very low cytotoxicity of the cationic CNCs in all tested experimental conditions. Overall, our results showed that cationic CNCs are suitable to be further investigated as immunomodulators and potential vaccine nanoadjuvants.

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