Biocidal agents

Examples of biocide agents used as motor fuel additives. 

Because chlorine is inactivated by blood, serum, feces, and protein-containing materials, surfaces should be cleaned before chlorine disinfectant is applied. Undissociated hypochlorous acid (HOCI) is the active biocidal agent. When pH is increased,... 

Bacteria are also responsible for destruction of wood, for example in cooling towers,20 by breaking down the cellulose fibers. Certain bacteria derive their metabolic energy from the iron(II)-iron(III) redox cycle. These iron bacteria can proliferate to the extent that they block pipes. In any case, they will discolor water. In addition, objectionable growths of algae can occur in water tanks or circuits, given even minimal supplies of nutrients. Consequently, biocidal agents are widely used in the treatment of industrial, as well as municipal, water supplies. 

Other biocidal agents that can be used in closed industrial water systems include copper(II) salts (which, however, can cause corrosion of metals), chlorinated phenols such as sodium pentachlorophenate (NaOCfiCls, which is toxic), and quaternary ammonium salts (lUN+X-). 

It seems likely that the future will see major developments in the use of metal complexes as bacteriocidal, viricidal, immunosuppressive, anti-arthritic and biocidal agents. One class of complexing agents that appears to have particular promise are the macrocyclic antibiotics, macrocyclic polyethers, polyamines and cryptates . In this group the ligand wraps around a metal ion to form a lipid-soluble complex... 

Because chlorine is inactivated by blood, serum, feces, and protein-containing materials, surfaces should be cleaned before chlorine disinfectant is applied. Undissociated hypochlorous acid (HOC1) is the active biocidal agent. When pH is increased, the less active hypochlorite ion, OC1 , is formed. When hypochlorite solutions contact formaldehyde, the carcinogen /v.v-chloromethyl is formed. Rapid evolution of irritating chlorine gas occurs when hypochlorite solutions are mixed with acid and urine. Solutions are corrosive to aluminum, silver, and stainless steel. 

Attack by organisms other than SRB. Ammonia and amines are produced by microbial decomposition of organic matter under both aerobic and anaerobic conditions (ammo-nification). (Stott)5 These compounds are oxidized to nitrite by aerobic bacteria such as Nitrosomonas or Nitrobacter species. Nitrobacter is very efficient at destroying the corrosion-inhibition properties, of nitrate-based corrosion inhibitors by oxidation, unless a biocidal agent is included in the formulation. The release of ammonia at the surfaces of heat-exchanger tubes has a detrimental effect. (Stott)5... 

Table 4.7. MECHANISMS OF SPORE RESISTANCE TO BIOCIDAL AGENTS...

During germination and/or outgrowth, spores become sensitive to biocidal agents [140-143], Some inhibitors (e.g. phenolics and parabens) prevent... 

Plasmid R124 alters the cell surface of E. coli cells such that they show enhanced resistance to the QAC, cetrimide, and other agents [299]. Generally, plasmids do not promote resistance in Gram-negative bacteria to biocidal agents [300], although hospital isolates may be more resistant to biocides than laboratory strains [301]. It is to be wondered whether an Mdr system is associated with this resistance. 

There is not, perhaps, the same urgency to develop new biocidal agents, although resistance to biocides can take many forms (Table 4.19). Nevertheless, more active, less toxic compounds would always provide welcome additions to the current, rather limited range. This is particularly true for new agents with mycobactericidal activity and the replacement of glutaralde-... 

Weston A, Assem ES. Possible link between anaphylactoid reactions to anaesthetics and chemicals in cosmetics and biocides. Agents Actions 1994 41(Spec No) C138-9. 

Response to a biocide depends upon the cellular stage of development. Sporulation, a process in which a bacterial spore develops from a vegetative cell, involves seven stages (I—VII Chapter 3) of these, stages IV-VII (cortex and coat development) are the most important in relation to the development of biocide resistance. Resistance to biocidal agents develops during sporulation and may be an early, intermediate or late/very late event. For example, resistance to chlorhexidine occurs at an intermediate stage, at about the same time as heat... 

Sterilization processes involve the application of a biocidal agent or physical microbial removal process to a product or preparation with the object... 

Moist heat has been recognized as an efficient biocidal agent from the early days of bacteriology,... 

Parabens (including methyl-, ethyl-, propyl-, and butylparaben) are used widely in pharmaceutical products as a biocidal agent. The majority of allergic reactions to parabens are observed after topical exposure. Delayed hypersensitivity contact dermatitis occurs more often in individuals with preexisting dermatitis. Immediate hypersensitivity after parenteral administration is rare. Although these... 

Patent Number US 5659047 A 19970819 POLYFLUOROALKYLTHIOPOLY(ETHYLIM IDAZOLIUM) COMPOUNDS, PREPARATION PROCESS AND THEIR USE AS BIOCIDAL AGENTS... 

The widespread agricultural applications of trialkyltin biocidal agents have greatly increased the relative exposure risks to workers handling these materials. Internationally, tin was recognized as a potential environmental contaminant at the Paris and Helsinki conventions in 1974 in later conventions, organotin compounds were moved to the black list. Due to the increasing use of... 

Polymers exhibiting quaternary nitrogen functionalities have commonly been used as biocidal agents [13-21], A number of polymeric disinfectants containing quaternary pyridinium groups, either in the backbone or as pendent groups, have been prepared and exhibit good antibacterial activity. 

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