Nanoconcentrations of of 1,9-dimethylmethylene blue (DMMB) associated to laser, LED or polarized light are highly effective on AmPDT carried out in aerobes and aerotolerant anaerobes Gram-positive bacteria

2020 ◽  
Author(s):  
Antônio Luiz B. Pinheiro ◽  
Fernando José P. Sampaio ◽  
Darcy Santos de Almeida ◽  
Pedro Jorge L. Crugeira ◽  
Susana Carla P. S. de Oliveira ◽  
...  
Keyword(s):  
Polarized Light ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Highly Effective

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 Novel modified QAC antimicrobial coatings: application, evaluation and functional determination

2021 ◽  
Author(s):  
Alexander Gabriel Caschera
Keyword(s):  
Polymer Surfaces ◽  
Gram Positive ◽  
Core Motif ◽  
Alkyl Chains ◽  
Gram Positive Bacteria ◽  
Coated Materials ◽  
Highly Effective ◽  
Solid Liquid ◽  
Air Interfaces ◽  
Ammonium Compounds

A series of novel quaternary ammonium compounds (QACs) previously synthesized by the Foucher Research Group containing the core motif R1-(CH2)3-N+ (CH3)2-(CH2)3-R2, where R1 represents functional groups responsible for anchoring the compound to various substrates and R2 represents moieties responsible for altering the activity and surface properties of coated materials are described. R1 groups include benzophenone (-O-C6H4-C(O)-C6H5) 1a-11a for anchoring to polymer surfaces, and organosilane (-Si(OCH3) 3b-10b for anchoring to textiles and fabrics, while R2 groups include linear alkyl chains (-(CH2)n-CH3; n = 11, 17) 1-2 and aryl or alkyl sulfonamide containing moieties (-NH-SO2-CXHY, x = 2-10; y = 5-11) 3-11. These compounds were tested for antimicrobial activity at solid/air interfaces (LDI) and were found highly effective against representative Gram-positive and Gram-negative bacteria (except 7a-8a, 11a). Selective solid/liquid antimicrobial testing (LRI) was performed on 1a, 5a and only 5a was found to be highly effective against Gram-positive bacteria.

scholarly journals Novel modified QAC antimicrobial coatings: application, evaluation and functional determination

2021 ◽  
Author(s):  
Alexander Gabriel Caschera
Keyword(s):  
Polymer Surfaces ◽  
Gram Positive ◽  
Core Motif ◽  
Alkyl Chains ◽  
Gram Positive Bacteria ◽  
Coated Materials ◽  
Highly Effective ◽  
Solid Liquid ◽  
Air Interfaces ◽  
Ammonium Compounds

A series of novel quaternary ammonium compounds (QACs) previously synthesized by the Foucher Research Group containing the core motif R1-(CH2)3-N+ (CH3)2-(CH2)3-R2, where R1 represents functional groups responsible for anchoring the compound to various substrates and R2 represents moieties responsible for altering the activity and surface properties of coated materials are described. R1 groups include benzophenone (-O-C6H4-C(O)-C6H5) 1a-11a for anchoring to polymer surfaces, and organosilane (-Si(OCH3) 3b-10b for anchoring to textiles and fabrics, while R2 groups include linear alkyl chains (-(CH2)n-CH3; n = 11, 17) 1-2 and aryl or alkyl sulfonamide containing moieties (-NH-SO2-CXHY, x = 2-10; y = 5-11) 3-11. These compounds were tested for antimicrobial activity at solid/air interfaces (LDI) and were found highly effective against representative Gram-positive and Gram-negative bacteria (except 7a-8a, 11a). Selective solid/liquid antimicrobial testing (LRI) was performed on 1a, 5a and only 5a was found to be highly effective against Gram-positive bacteria.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Elaf Ayad Kadhem ◽  
Miaad Hamzah Zghair ◽  
Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽  
Hussam H. Tizkam ◽  
Shoeb Alahmad
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Diffusion Method ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Magnesium Oxide Nanoparticles ◽  
Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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