Antimicrobial compound

LAB produce several compounds with antimicrobial properties as a result of nutrient competition with other microorganisms growing in the same niche. These antimicrobial active metabolites consist of nonspecific antimicrobial substances such as short-chain fatty acids (formic, acetic, propionic, butyric, and lactic acids), ethanol and hydrogen peroxide, and toxins including bacteri-ocins (nisin, reuterin, reutericyclin, pediocin, lacticin, enterocin, and others). 

Bacteriocins have been used to control spoilage and pathogenic bacteria in foods offering several benefits such as prolongation of the product shelf life, reduction of the risk of foodborne disease transmission, and decrease in the use of chemical compounds as preservatives and in the intensity of heat treatments to achieve high-quality foods [37, 52]. 

Bacteriocins can be e i situ added to foods as food ingredients (purified or semipurified bacteriocins, or as a previously fermented product with a 

Interesting metabolites LAB involved Applications/ Commercial names functions References 

Nisin Lc. lactis Food preservative in Nisaplin (Danisco) salami production [53, 60, 61] 

A more conventional classification of antibiotics is based on targets or mechanisms of action, categorizing antibiotics into five main groups  

Antibiotics that inhibit bacterial cell wall biosynthesis 

Antibiotics that disrupt the integrity of cell membranes 

Typical classes and examples within these categories as they apply to what is currently most prescribed on the U.S. market are summarized in Table 1.8. The targets in groups 1 and 4 are unique in bacteria and absent in humans and other animals, whereas groups 2, 3, and 5 have human counterparts that are structurally different between prokaryotes and eukaryotes. These differences in targets make the use of antibiotics selective for bacteria with little or no effect on eukaryotic cells from a therapeutic perspective. However, that does not mean that antimicrobial compounds are completely inert to eukaryotes. The mechanisms that block bacterial protein synthesis, block DNA replication, and those that disrupt membrane integrity affect membrane pores. 

General Mechanism Class Characteristics and Specific Mechanisms Examples Remarks 

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Imidazole and imidazoline derivatives have provided some useful antimicrobial compounds (Fig. 7). Metronidazole [433-48-1]... 

Choice of the most appropriate antimicrobial compound for a particular purpose depends on ... 

In order to understand current approaches for prevention and control of biofilms, we must first consider the reasons for the failure of conventional antimicrobial protocols. There are thought to be three main reasons as to why biofilm bacteria out-survive their planktonic counterparts during antimicrobial treatments (reviewed by McBain et a/.16).These are i) poor penetration of antimicrobial compounds due to the presence and turn-over of exopolymer slime (glycocalyx) ii) the imposition of extreme nutrient limitation within the depths of the biofilm community and the co-incident expression of metabolically-dormant, recalcitrant phenotypes and (iii) the expression of attachment-specific phenotypes that are radically different and intrinsically less susceptible than unattached ones. 

An intuitive explanation of biofilm drug resistance is that antimicrobial compounds are physically excluded from the community by the barrier properties of the glycocalyx. Such intuition however envisages that the glycocalyx functions as a biocide-impermeable umbrella, but since it generally possesses a diffusivity approximating that... 

The classic seed burial studies of W. J. Beal and his successors have shown seeds of at least one weed species, Moth Mullein (Verbascum blattaria L.) can remain viable in soil for a peiod of 100 years, whereas three species continued to germinate after 80 years of burial (30). Weed seeds not only resist decay by soil microbes, but they vary in dormancy characteristics. There is considerable evidence that chemical inhibitors are responsible for both phenomena. Unsaturated lactones and phenolic compounds in particular, are potent antimicrobial compounds present in many seeds (4J. Fruits and seeds are also known to contain diverse germination inhibitors including phenolic compounds, flavonoids and/or their glycosides and tannins. Unique methods to destroy inhibitors could provide an excellent weed management strategy. 

Triclosan is an antimicrobial compound widely used in household products, including cosmetics, oral sanitary products, detergents, etc. Thence, it is not surprising that it was detected in concentrations of approximately 1,000 ng/g in treated sludge and 5,000 ng/g in biological sludge from an urban WWTP in Spain [48],... 

Several bacteria in the natural gut flora or non-pathogenic bacteria which can colonise the gut have been shown to have preventive or even therapeutic effects on pathogens. Most commonly used and studied are bifidobacteria and lactobacilli (see Fig. 13.2) they have been shown to stimulate the innate immune system to produce cytokines, antimicrobial compounds and other metabolites affecting either the host and/or enteric bacteria (Aattouri et al., 2001 Xuan et al., 2001 Kralik et al, 2004 Scharek et al., 2005 Tannock, 2005 Davis et al., 2006). 

Antimicrobial acrylic fibers, 11 215-219 Antimicrobial agents, 12 31. See also Antimicrobial compounds in continuous-filament yarns, 19 758 as preservatives, 12 57-59 silylating agents and, 22 700 as soap bar additives, 22 746 sulfonamides as, 23 494 Antimicrobial compounds, microbiological methods for determining, 20 132 Antimicrobial nanoemulsion technology, 3 630-631... 

Aga, H., Shibuya, T., Sugimoto, T., Kurimoto, M. and Nakajima, S. (1994) Biosci. Biotech. Biochem., Isolation and identification of antimicrobial compounds in Brazilian propolis, 58, 945-946. 

Watanabe M et al (2005) Cloning and characterization of saponin hydrolases from Aspergillus oryzae and Eupenicillium brefeldianum. Biosci Biotechnol Biochem 69(11) 2178 Osbourn A (1996) Preformed antimicrobial compounds and plant defence against fungal attack. Plant Cell 8 1821... 

A solution containing chlorine dioxide concentrations of approximately 9.7-11.4 mg/L was nonirritating to the skin of mice in a 48-hour test (Shi and Xie 1999). Moderate to severe erythema was observed in rabbits following repeated daily applications of Alcide, an antimicrobial compound consisting of solutions of sodium chlorite and lactic acid that produce chlorine dioxide when mixed (Abdel-Rahman et al. 1987b). However, levels of exposure to sodium chlorite or chlorine dioxide could not be quantified. 

Dermal absorption of C1 was measured in rats following 10 daily applications of Alcide, an antimicrobial compound consisting of solutions of sodium chlorite and lactic acid that produce chlorine dioxide when... 

Urinary excretion of C1 was observed in rats that had been administered Alcide, an antimicrobial compound consisting of sodium chlorite and lactic acid that form chlorine dioxide when mixed (Scatina et al. 1984). The rats had received 10 daily dermal applications, followed by an application of radiolabeled Alcide. Urinary excretion was greatest in the first 24 hours post application the half-time of urinary elimination was 64 hours. The excreted radioactivity consisted of approximately equal portions of chloride ion and chlorite. No radioactivity was detected in feces or expired air. 

Scatina J, Abdel-Rahman MS, Gerges SE, et al. 1984. Pharmacodynamics of Alcide, a new antimicrobial compound, in rat and rabbit. Fundam Appl Toxicol 4 479-484. 

Triclosan is a broad-spectrum antimicrobial compound. It was originally used in soaps, antiperspirants, and cosmetic toiletries as a germicide. Today, triclosan is incorporated into toothpaste because of its wide spectrum of antimicrobial activities and low toxicity. 

Watanabe, M., Y. Sakai, T. Teraoka, OS026 et al. Novel C19-kaurane type of diterpenes (oryzalide A), a new antimicrobial compound isolated from healthy leaves of a bacterial leaf blight OS027 resistant cultivar of rice plant. Agr... 

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