scholarly journals The Mechanism of Action of Ginkgolic Acid (15:1) against Gram-Positive Bacteria Involves Cross Talk with Iron Homeostasis

2022 ◽  
Author(s):  
Zewen Wen ◽  
Yuxi Zhao ◽  
Zhengyang Gong ◽  
Yuanyuan Tang ◽  
Yanpeng Xiong ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Natural Product ◽  
Iron Homeostasis ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Ginkgolic Acid ◽  
Wide Range ◽  
Novel Antibiotics

The increasing emergence of infectious diseases associated with multidrug-resistant Gram-positive pathogens has raised the urgent need to develop novel antibiotics. GA (15:1) is a natural product derived from Ginkgo biloba and possesses a wide range of bioactivities, including antimicrobial activity.

scholarly journals Nisin H Is a New Nisin Variant Produced by the Gut-Derived Strain Streptococcus hyointestinalis DPC6484

2015 ◽  
Vol 81 (12) ◽  
pp. 3953-3960 ◽  
Author(s):  
Paula M. O'Connor ◽  
Eileen F. O'Shea ◽  
Caitriona M. Guinane ◽  
Orla O'Sullivan ◽  
Paul D. Cotter ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Immune System ◽  
Bacteriocin Production ◽  
Genetic Determinants ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Similar Gene ◽  
Strain Genome

ABSTRACTAccumulating evidence suggests that bacteriocin production represents a probiotic trait for intestinal strains to promote dominance, fight infection, and even signal the immune system. In this respect, in a previous study, we isolated from the porcine intestine a strain ofStreptococcus hyointestinalisDPC6484 that displays antimicrobial activity against a wide range of Gram-positive bacteria and produces a bacteriocin with a mass of 3,453 Da. Interestingly, the strain was also found to be immune to a nisin-producing strain. Genome sequencing revealed the genetic determinants responsible for a novel version of nisin, designated nisin H, consisting of thenshABTCPRKGEFgenes, with transposases encoded betweennshPandnshRand betweennshKandnshG. A similar gene cluster is also found inS. hyointestinalisLMG14581. Notably, the cluster lacks an equivalent of the nisin immunity gene,nisI. Nisin H is proposed to have the same structure as the prototypical nisin A but differs at 5 amino acid positions—Ile1Phe (i.e., at position 1, nisin A has Ile while nisin H has Phe), Leu6Met, Gly18Dhb (threonine dehydrated to dehydrobutyrine), Met21Tyr, and His31Lys—-and appears to represent an intermediate between the lactococcal nisin A and the streptococcal nisin U variant of nisin. Purified nisin H inhibits a wide range of Gram-positive bacteria, including staphylococci, streptococci,Listeriaspp., bacilli, and enterococci. It represents the first example of a natural nisin variant produced by an intestinal isolate of streptococcal origin.

scholarly journals Antimicrobial Nodule-Specific Cysteine-Rich Peptides Induce Membrane Depolarization-Associated Changes in the Transcriptome of Sinorhizobium meliloti

2013 ◽  
Vol 79 (21) ◽  
pp. 6737-6746 ◽  
Author(s):  
Hilda Tiricz ◽  
Attila Szűcs ◽  
Attila Farkas ◽  
Bernadett Pap ◽  
Rui M. Lima ◽  
...  
Keyword(s):  
Stress Responses ◽  
Sinorhizobium Meliloti ◽  
Antimicrobial Agents ◽  
Cellular Functions ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Peptide Family ◽  
Wide Range ◽  
Natural Target

ABSTRACTLeguminous plants establish symbiosis with nitrogen-fixing alpha- and betaproteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the inverted repeat-lacking clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-rich (NCR) peptide family composed of close to 600 members. Among the few tested NCR peptides, cationic ones had antirhizobial activity measured by reduction or elimination of the CFU and uptake of the membrane-impermeable dye propidium iodide. Here, the antimicrobial spectrum of two of these peptides, NCR247 and NCR335, was investigated, and their effect on the transcriptome of the natural targetSinorhizobium melilotiwas characterized. Both peptides were able to kill quickly a wide range of Gram-negative and Gram-positive bacteria; however, their spectra were only partially overlapping, and differences were found also in their efficacy on given strains, indicating that the actions of NCR247 and NCR335 might be similar though not identical. Treatment ofS. meliloticultures with either peptide resulted in a quick downregulation of genes involved in basic cellular functions, such as transcription-translation and energy production, as well as upregulation of genes involved in stress and oxidative stress responses and membrane transport. Similar changes provoked mainly in Gram-positive bacteria by antimicrobial agents were coupled with the destruction of membrane potential, indicating that it might also be a common step in the bactericidal actions of NCR247 and NCR335.

scholarly journals In Vitro Study of Antimicrobial Percutaneous Nephrostomy Catheters for Prevention of Renal Infections

2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Nylev Vargas-Cruz ◽  
Ruth A. Reitzel ◽  
Joel Rosenblatt ◽  
Mohamed Jamal ◽  
Ariel D. Szvalb ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biofilm Formation ◽  
In Vitro Study ◽  
Percutaneous Nephrostomy ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Fungal Organisms

ABSTRACT Percutaneous nephrostomy (PCN) catheters are the primary method for draining ureters obstructed by malignancy and preventing a decline of renal function. However, PCN catheter-related infections, such as pyelonephritis and urosepsis, remain a significant concern. Currently, no antimicrobial PCN catheters are available for preventing infection complications. Vascular catheters impregnated with minocycline-rifampin (M/R) and M/R with chlorhexidine coating (M/R plus CHD) have previously demonstrated antimicrobial activity. Therefore, in this study, we examined whether these combinations could be applied to PCN catheters and effectively inhibit biofilm formation by common uropathogens. An in vitro biofilm colonization model was used to assess the antimicrobial efficacy of M/R and M/R-plus-CHD PCN catheters against nine common multidrug-resistant Gram-positive and Gram-negative uropathogens as well as Candida glabrata and Candida albicans. Experimental catheters were also assessed for durability of antimicrobial activity for up 3 weeks. PCN catheters coated with M/R plus CHD completely inhibited biofilm formation for up to 3 weeks for all the organisms tested. The reduction in colonization compared to uncoated PCN catheters was significant for all Gram-positive, Gram-negative, and fungal organisms (P < 0.05). M/R-plus-CHD PCN catheters also produced significant reductions in biofilm colonization relative to M/R PCN catheters for Enterobacter spp., Escherichia coli, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, C. glabrata, and C. albicans (P < 0.05). M/R-plus-CHD PCN catheters proved to be highly efficacious in preventing biofilm colonization when exposed to multidrug-resistant pathogens common in PCN catheter-associated pyelonephritis. M/R-plus-CHD PCN catheters warrant evaluation in a clinical setting to assess their ability to prevent clinically relevant nephrostomy infections.

scholarly journals Comparative Analysis of Antimicrobial Activities of Valinomycin and Cereulide, the Bacillus cereus Emetic Toxin

2011 ◽  
Vol 77 (8) ◽  
pp. 2755-2762 ◽  
Author(s):  
Marcel H. Tempelaars ◽  
Susana Rodrigues ◽  
Tjakko Abee
Keyword(s):  
Antimicrobial Activity ◽  
Comparative Analysis ◽  
Membrane Potential ◽  
Bacillus Cereus ◽  
Antimicrobial Activities ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Ph Range ◽  
Main Component

ABSTRACTCereulide and valinomycin are highly similar cyclic dodecadepsipeptides with potassium ionophoric properties. Cereulide, produced by members of theBacillus cereusgroup, is known mostly as emetic toxin, and no ecological function has been assigned. A comparative analysis of the antimicrobial activity of valinomycin produced byStreptomycesspp. and cereulide was performed at a pH range of pH 5.5 to pH 9.5, under anaerobic and aerobic conditions. Both compounds display pH-dependent activity against selected Gram-positive bacteria, includingStaphylococcus aureus,Listeria innocua,Listeria monocytogenes,Bacillus subtilis, andBacillus cereusATCC 10987. Notably,B. cereusstrain ATCC 14579 and the emeticB. cereusstrains F4810/72 and A529 showed reduced sensitivity to both compounds, with the latter two strains displaying full resistance to cereulide. Both compounds showed no activity against the selected Gram-negative bacteria. Antimicrobial activity against Gram-positive bacteria was highest at alkaline pH values, where the membrane potential (ΔΨ) is the main component of the proton motive force (PMF). Furthermore, inhibition of growth was observed in both aerobic and anaerobic conditions. Determination of the ΔΨ, using the membrane potential probe DiOC2(3) (in the presence of 50 mM KCl) in combination with flow cytometry, demonstrated for the first time the ability of cereulide to dissipate the ΔΨ in sensitive Gram-positive bacteria. The putative role of cereulide production in the ecology of emeticB. cereusis discussed.

scholarly journals Novel Antibiotics for Multidrug-Resistant Gram-Positive Microorganisms

2019 ◽  
Vol 7 (8) ◽  
pp. 270 ◽  
Author(s):  
Koulenti ◽  
Xu ◽  
Mok ◽  
Song ◽  
Karageorgopoulos ◽  
...  
Keyword(s):  
Healthcare Costs ◽  
Multidrug Resistant ◽  
Current Evidence ◽  
Efficacy And Safety ◽  
Antibiotic Agent ◽  
Gram Positive ◽  
Resistance Development ◽  
Gram Positive Bacteria ◽  
Highly Effective ◽  
Novel Antibiotics

Increasing multidrug-resistance to Gram-positive pathogens, particularly to staphylococci, enterococci and streptococci, is a major problem, resulting in significant morbidity, mortality and healthcare costs. In recent years, only a small number of novel antibiotics effective against Gram-positive bacteria has been approved. This review will discuss the current evidence for novel branded antibiotics that are highly effective in the treatment of multidrug-resistant infections by Gram-positive pathogens, namely ceftobiprole, ceftaroline, telavancin, oritavancin, dalbavancin, tedizolid, besifloxacin, delafloxacin, ozenoxacin, and omadacycline. The mechanism of action, pharmacokinetics, microbiological spectrum, efficacy and safety profile will be concisely presented. As for any emerging antibiotic agent, resistance is likely to develop against these highly effective antibiotics. Only through appropriate dosing, utilization and careful resistance development monitoring will these novel antibiotics continue to treat Gram-positive pathogens in the future.

scholarly journals DETERMINATION OF ANTIBACTERIAL ACTIVITY OF SOME IMPORTANT SPICES

2015 ◽  
Vol 3 (10) ◽  
pp. 57-64
Author(s):  
Ranganathan Kapilan
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Maximum Activity ◽  
Gram Negative Bacteria ◽  
Alcoholic Extract ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Wide Range

Wide range of plant extracts are used for medicinal purposes as they are very cheap, efficient, harmless and do not cause any side effects. Spices are parts of different plants and they add special aroma and taste to the food preparations. The aim of the study was to determine the antimicrobial activity of some important naturally grown spices against gram positive and gram negative pathogenic bacteria. Antibacterial activity of the spices was tested against gram positive bacteria Bacillus pumilus, Bacillus cereus and Staphylococcus aureus and gram negative bacteria Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa using aqueous, ethanolic, methanolic and liquid nutrient extracts. Among all the extracts tested alcoholic extracts of Cardamom (Elettaria cardamom), clove (Eugenia caryophyllus) and lemongrass (Cymbopogoncitratus) showed maximum antimicrobial activity against gram negative bacteria while alcoholic extract of Cardamom (Elettaria cardamom) and lemongrass (Cymbopogoncitratus) showed maximum activity against gram positive bacteria. All the spices tested in this study proved that they have antibacterial activity and the maximum activity index (1.39) was exhibited by the ethanol extract of cardamom against E.coli.

scholarly journals Cerecidins, Novel Lantibiotics from Bacillus cereus with Potent Antimicrobial Activity

2014 ◽  
Vol 80 (8) ◽  
pp. 2633-2643 ◽  
Author(s):  
Jian Wang ◽  
Li Zhang ◽  
Kunling Teng ◽  
Shutao Sun ◽  
Zhizeng Sun ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Multidrug Resistant ◽  
Regulator Gene ◽  
Gram Positive ◽  
Content Type ◽  
Pcr Screening ◽  
Gram Positive Bacteria ◽  
Immunity Genes ◽  
Natural Variants ◽  
Vancomycin Resistant

ABSTRACTLantibiotics are ribosomally synthesized and posttranslationally modified antimicrobial peptides that are widely produced by Gram-positive bacteria, including many species of theBacillusgroup. In the present study, one novel gene cluster coding lantibiotic cerecidins was unveiled inBacillus cereusstrain As 1.1846 through genomic mining and PCR screening. The designatedcerlocus is different from that of conventional class II lantibiotics in that it included seven tandem precursorcerAgenes, one modification gene (cerM), two processing genes (cerTandcerP), one orphan regulator gene (cerR), and two immunity genes (cerFandcerE). In addition, one unprecedented quorum sensing component,comQXPA, was inserted betweencerMandcerR. The expression of cerecidins was not detected in this strain ofB. cereus, which might be due to repressed transcription ofcerM. We constitutively coexpressedcerAgenes andcerMinEscherichia coli, and purified precerecidins were proteolytically processed with the endoproteinase GluC and a truncated version of putative serine protease CerP. Thus, two natural variants of cerecidins A1 and A7 were obtained which contained two terminal nonoverlapping thioether rings rarely found in lantibiotics. Both cerecidins A1 and A7 were active against a broad spectrum of Gram-positive bacteria. Cerecidin A7, especially its mutant Dhb13A, showed remarkable efficacy against multidrug-resistantStaphylococcus aureus(MDRSA), vancomycin-resistantEnterococcus faecalis(VRE), and evenStreptomyces.

scholarly journals Antimicrobial Activity and Spectrum of PPI-0903M (T-91825), a Novel Cephalosporin, Tested against a Worldwide Collection of Clinical Strains

2005 ◽  
Vol 49 (8) ◽  
pp. 3501-3512 ◽  
Author(s):  
Helio S. Sader ◽  
Thomas R. Fritsche ◽  
Koné Kaniga ◽  
Yigong Ge ◽  
Ronald N. Jones
Keyword(s):  
Antimicrobial Activity ◽  
Multidrug Resistant ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Similar Activity ◽  
Gram Positive Bacteria ◽  
Medical Centers

ABSTRACT PPI-0903M is a novel N-phosphono-type cephalosporin active against oxacillin-resistant staphylococci and many other gram-positive organisms. This study evaluated the in vitro activity and spectrum of PPI-0903M against 1,478 recent clinical isolates collected from 80 medical centers (22 countries). PPI-0903M demonstrated broader in vitro activity against gram-positive bacteria, particularly against multidrug-resistant staphylococci and streptococci of current clinical concern, than currently available extended-spectrum cephalosporins while maintaining similar activity against gram-negative pathogens.

scholarly journals Enaminone-Derived Pyrazoles with Antimicrobial Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mashooq Ahmad Bhat ◽  
Mohamed A. Al-Omar ◽  
Ahmed M. Naglah ◽  
Abdul Arif Khan
Keyword(s):  
Antimicrobial Activity ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Disc Diffusion ◽  
Initial Screening ◽  
Gram Positive ◽  
Gram Negative ◽  
Disc Diffusion Assay ◽  
Gram Positive Bacteria ◽  
Diffusion Assay

A series of pyrazoles derived from the substituted enaminones were synthesized and were evaluated for antimicrobial activity. All the compounds were characterized by the spectral data and elemental analysis. The synthesized compounds were initially screened for their antimicrobial activity against ATCC 6538, NCTC 10400, NCTC 10418, and ATCC 27853. During initial screening, compounds (P1, P6, and P11) presented significant antimicrobial activity through disc diffusion assay. These compounds were further evaluated for antimicrobial activity at different time points against Gram-positive and Gram-negative bacteria and presented significant activity for 6 hours. The activity was found to be greater against Gram-positive bacteria. In contrast at 24 hours, the activity was found only against Gram-positive bacteria except compound (P11), showing activity against both types of bacteria. Compound (P11) was found to have highest activity against both Gram-positive and Gram-negative bacteria.

Antimicrobial Activity of Isopteropodine

2005 ◽  
Vol 60 (5-6) ◽  
pp. 385-388 ◽  
Author(s):  
Rubén García ◽  
Cesia Cayunao ◽  
Ronny Bocic ◽  
Nadine Backhouse ◽  
Carla Delporte ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Gram Positive ◽  
Uncaria Tomentosa ◽  
Gram Positive Bacteria

Bioassay-directed fractionation for the determination of antimicrobial activity of Uncaria tomentosa, has led to the isolation of isopteropodine (0.3%), a known Uncaria pentacyclic oxindol alkaloid that exhibited antibacterial activity against Gram positive bacteria.

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