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Legionella Ecology
Published in Harriet A. Burge, Bioaerosols, 2020
Isolation of Legionellae. Recovery of Legionella from environmental samples continues to be difficult. This is particularly true because Legionella generally comprises less than 1% of the total bacterial population in environmental samples and is easily out-competed by other organisms in the environment. As a result, the levels of Legionella observed on selective media greatly underestimate the density of the bacterium in the natural environment. Attempts to overcome this problem have included the use of “selective” media consisting of a buffered charcoal yeast-extract base supplemented with iron, cysteine, and a variety of bacterial inhibitors. Wadowsky and Yee (1981) and Vickers et al. (1981) described a glycine-vancomycin-polymyxin B (DGVP) agar, which incorporated glycine, the antibiotics vancomycin and polymyxin B as selective agents, and the dyes bromothymol blue and bromocresol purple. Bopp et al. (1981) produced a medium containing cephalothin, colistin, cycloheximide, and vancomycin. Edelstein (1982) described a medium containing glycine, polymyxin B, vancomycin, and anisomycin, as well as bromothymol blue and bromocresol purple. Although these media are designed to inhibit other bacteria and select for the recovery of legionellae, many aquatic and terrestrial bacteria will grow on all of the above media. There is at present no defined or complex medium that allows the full expression of Legionella’s capability as demonstrated by DFA, and, currently, there is still no selective medium that is specific for legionellae.
Dendrimers: Emerging Anti-Infective Nanomedicines
Published in Bhupinder Singh, Rodney J. Y. Ho, Jagat R. Kanwar, NanoBioMaterials, 2018
Taking advantage of the unique properties of peptide dendrimers over their monomeric counterparts, Bruschi et al. (2010) developed a novel antimicrobial dendrimeric peptide, named SB041, by linking four units of pyr EKKIRVRLSA peptide to lysine core using 5-amino valeric acid chain (Figure 6.2). This peptide showed antimicrobial activity towards gram-negative (as well as some activity towards gram-positive) bacteria. But its activity was observed to prefer gram-negative bacteria equivalent to commercially available peptide antibiotics, polymyxin B and colistin. In vitro activity showed a high affinity of SB041 towards lipolysaccharides (LPS) of E. coli (Bruschi et al., 2010).
Advanced technical textile products
Published in T. Matsuo, Textile Progress, 2019
The absorbent fiber can selectively remove the endotoxin from blood, which is the cause material of septicemia. It is a bicomponent fiber of sea-and-island type whose sheath material is polystyrene. Polymyxin B, which is a polypeptide antibionic, is chemically fixed to the porous styrene sheath of the fiber, as shown in Figure 24. The removal is carried out on the basis of the chemical affinity between the endotoxin and polymyxin B. The knitted fabric made of the adsorbent fiber is wound on a tube and contained in the module, as shown in Figure 25. The circulating blood in the treatment system is purified while passing through the module.
Facile preparation of nanomicelles using polymyxin E for enhanced antitumor effects
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Xifa Lan, Quanling Guo, Zhiwei Liu, Kai Liu, Jinfeng He, Ruyu Li, Haotian Sun, Wenxiu Yao, Longgang Wang
Natural peptides have fixed molecular weight and can be isolated from living organisms without complex synthetic process. Most of natural peptides have high biocompatibility and biodegradability due to the presence of enzyme in vivo [21,22]. Polymyxin E (PE) is a kind of antibiotics to treat infections caused by multidrug-resistant bacteria [23]. PE is a kind of cyclic lipopeptide antibiotics and against Gram-negative bacteria [24]. The outer membrane of Gram-negative bacteria has many polyanionic lipopolysaccharides which regulate the permeability of their outer membrane. The PE has high affinity with polyanionic lipopolysaccharides [25]. PE has a heptapeptide macrocycle, an exocyclic tripeptide, and an acyl tail [26–28]. Thus, PE has amphipathic structure [28], and should assemble into PE micelles in solution, which may be used for delivery the hydrophobic drug molecules.
Preparation, characterization and application of curcumin based polymeric bio-composite for efficient removal of endotoxins and bacterial cells from therapeutic preparations
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Pragya Prakash, Hare Ram Singh, Santosh Kumar Jha
LPS removal from blood needs a robust binding force as LPS is already bound to monocytes or lipoproteins [9]. An antibiotic agent Polymyxin B holds healthy bactericidal activity for gram-negative bacteria and also has a strong affinity towards endotoxin. However, intravenous injection of PL-B (Polymyxin-B) is not possible due to its neuro and nephrotoxicity. Alternatives are to utilize this as an absorbent for endotoxin when PL-B is bound to a substrate. Substrates exploited for the purpose are polystyrene and polypropylene conjugated fibers. For the purpose, PL-B is covalently immobilized on the surface of the fibers through the chemical reaction between the primary amino groups of PL-B and an active chlorine atom of the functional groups [10].
Evaluation of the proinflammatory effects of contaminated bathing water
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Anas A. Sattar, Wondwossen Abate, Gyorgy Fejer, Graham Bradley, Simon K. Jackson
Composite samples of marine bathing water were collected on 10 occasions over the summer of 2012 (UK bathing season) at Challaborough beach, Devon, UK (Latitude: 50.287159, Longitude: −3.899052). This beach is a popular bathing, body boarding and surfing beach that is a horseshoe-shaped bay virtually divided by a stream that runs from a valley down into the sea (Sattar, Jackson, and Bradley 2014). In the event of heavy rain, a runoff from the surrounding areas which constitutes a cattle habitat enters the stream and eventually reaches the beach and adversely affects the quality of the bathing water. For the microbiological investigation, samples were collected in 500 ml disposable, sterile, screw-capped wide mouth pots. Water samples for total LPS determination were collected in 50 ml LPS-free Falcone™ tubes (VWR, UK); then, aliquoted into glass tubes and stored at −20°C until assay to inhibit bacterial growth. Part of these water samples was used to investigate the number of FIB and correlated to the total levels of LPS (Sattar, Jackson, and Bradley 2014). Four water samples were selectively chosen in the current study representing different contamination levels based upon bathing water quality classification implemented by the European Union bathing water quality 2006/7/ec (EU 2006). Water sample criteria are presented in Table 1. The LPS content of marine bathing water in the presence or absence of polymyxin B (PMB) was assessed using the Kinetic QCL™ method as described previously (Sattar, Jackson, and Bradley 2014). Polymyxin B (PMB) is an antibiotic that binds to the lipid A moiety of LPS leading to neutralization of LPS when it is subsequently utilized to stimulate immune cells (Cardoso et al. 2007)