Antisepsis

A number of disinfectants apparentiy owe their activity to formaldehyde, although there is argument on whether some of them function by other mechanisms. In this category, the dmg with the longest history is hexamethylenetetramine (hexamine, urotropin) [100-97-0] which is a condensation product of formaldehyde and ammonia that breaks down by acid hydrolysis to produce formaldehyde. Hexamine was first used for urinary tract antisepsis. Other antimicrobials that are adducts of formaldehyde and amines have been made others are based on methylolate derivations of nitroalkanes. The apphcations of these compounds are widespread, including inactivation of bacterial endotoxin preservation of cosmetics, metal working fluids, and latex paint and use in spin finishes, textile impregnation, and secondary oil recovery (117). 

The intended application of an antimicrobial agent, whether for preservation, antisepsis or disinfection, will influence its selection and also affect its performance. For example, in medicinal preparations the ingredients in the formulation may antagonize preservative activity. The risk to the patient will depend on whether the antimicrobial is in close contact with a break in the skin or mucous membranes or is introduced into a sterile area of the body. 

The following section presents in alphabetical order by chemical grouping the agents most often employed for disinfection, antisepsis and preservation. This information is summarized in Table 10.6. 

A number of organic chlorine, or chloramine, compounds are now available for disinfection and antisepsis. These are the N-chloro (=N-C1) derivatives of, for example, sulphonamides giving compounds such as chloramine-T and dichloramine-T and halazone (Fig. 10.5), which may be used for the disinfection of contaminated drinking water. 

The antimicrobial activity of iodine is less dependent than chlorine on temperature and pH, though alkaline pH should be avoided. Iodine is also less susceptible to inactivation by organic matter. Disadvantages in the use of iodine in skin antisepsis are staining of skin and fabrics coupled with possible sensitizing of skin and mucous membranes. 

The amount of free iodine the solution can generate is termed the available iodine. This acts as a reservoir for active iodine releasing it when required and therefore largely avoiding the harmful side-effects of high iodine concentration. Consequently, when used for antisepsis, iodophors should be allowed to remain on the skin for 2 minutes to obtain full advantage of the sustained-release iodine. 

Bidawid, S., Malik, N., Adegbunrin, O., Sattar, S. A., and Farber, J. M. (2004). Norovirus cross-contamination during food handling and interruption of virus transfer by hand antisepsis Experiments with feline calicivirus as a surrogate. J. Food Prot. 67,103-109. 

Preoperative colon preparation Intestinal antisepsis Oral antibiotics Erythromycin-neomycin... 

Recent restrictions in the use of hexachlorophene preparations for antisepsis and the recommendation that povidone-iodine (Betadine) be used in its place will undoubtedly lead to increased thyroid function assay... 

A6. Anonymous, Povidone—iodine (Betadine) for surgical antisepsis. Med. Lett. 11, 100 (1969). 

Antisepsis Application of an agent to living tissue for the purpose of preventing infection... 

Repeated surgical skin antisepsis and hand washing did not increase serum iodine concentrations, but produced a small increase in iodine content in the 24-hour urine (4). 

Colcleuth RG. Distribution protein binding of betadine ointment in burn wounds. In Altemeier WA, editor. II World Congress/Antisepsis Proceedings. New York HP Publishing Co, 1980 122-3. 

Dyes (acridines, triphenylmethane) Metal chelate complexes Antisepsis Antisepsis Now little used... 

Organic mercury compounds Silver compounds Preservation or antisepsis Application to wounds Important pharmaceutical preservations Effective against Pseudomonas aeruginosa... 

Tuffnell, D.J. et al., Methicillin resistant Staphylococcus aureus the role of antisepsis in the control of an outbreak. J. Hosp. Infect. 10, 255-259, 1987. 

The lower aliphatic alcohols (ethanol, isopropanol, 2-propanol, A-propanol, and 1-propanol) are widely used for skin antisepsis. In appropriate concentrations, these alcohols are bactericidal to most of the common pathogenic bacteria, but some rare species survive and can grow, especially since these alcohols are inactive against dried spores. 

Pseudomonas bacteremia has been attributed to the use of material in open-heart surgery that was stored in accidentally contaminated benzalkonium solutions, and after cardiac catheterization caused by inadequate disinfection of the catheters with benzalkonium solutions. In 1961, about 15 patients were reported with Pseudomonas infections caused by cotton pledgets kept in a contaminated aqueous solution used for skin antisepsis before intravenous and intramuscular injection (8). In 1976 there were outbreaks of Pseudomonas cepacia infections in two American general hospitals (9) and pseudobacteremia Pseudomonas cepacia or Enterobacter) caused by contamination of blood cultures in 79 patients in whom contaminated aqueous benzalkonium solutions were used for skin and antisepsis before venepuncture and due to contamination of the samples (SEDA-11, 490) (10). 

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