Agent Mechanisms of Action Comments Surfactants. Membrane Disruption; increased penetration Denature proteins; Disrupts lipids

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3 Agent Mechanisms of Action Comments Surfactants Quats (cationic detergent) Organic acids and bases Membrane Disruption; increased penetration Denature proteins; Disrupts lipids High/low ph Soaps; detergents Antiseptic - benzalconium chloride, Cepacol; Disinfectant Mold and Fungi inhibitors; e.g., benzoate of soda Heavy Metals Denature protein Antiseptic & Disinfectant; Silver Nitrate Halogens Alcohols Oxidizing agent Disrupts cell membrane Denatures proteins; Disrupts lipids Antiseptic - Iodine (Betadine) Disinfectant - Chlorine (Chlorox) Antiseptic & Disinfectant Ethanol and isopropyl Phenolics Disrupts cell membrane Disinfectant Irritating odor Aldehydes Denature proteins Gluteraldehyde - disinfectant (Cidex); Formaldehyde - disinfectant Ethylene Oxide Denaturing proteins Used in a closed chamber to sterilize Oxidizing agents Denature proteins Hydrogen peroxide antiseptic; Hydrogen peroxide disinfectan; Benzoyl peroxide antiseptic

4 The Ideal Disinfectant Broadly active (killing pathogens) Not poisonous (or otherwise harmful) Penetrating (to pathogens) Resistant to inactviation Not damaging to non-livingmaterials Stable Easy to work with Otherwise not unpleasant

5 Cleaning and disinfection of instrument &surfaces Classification of chemical disinfectants. Risk stratification of hospital sections. Classification of medical devices

6 Level of disinfection Spores TB Vegetative bacteria Fungi Nonlipid & small viruses Lipid & mediumsize viruses High + * Inter-mediate /- + Low /- +/- + * high-level disinfectants may not be able to kill large numbers of spores

7 Low risk area : Financial, Official Moderate risk areas : Hospital ordinarily wards High risk areas : ICU, NICU, Isolated rooms Very high risk areas : Operation rooms

8 Class of item Use of item Example Critical Semi-critical Non-critical Enter vascular system or sterile body tissues Comes in contact with intact mucous membranes Touches only intact skin Hypodermic needle, Scalpels and other surgical instruments, Biopsy forceps Vaginal spec., Anaesthetic equipment, flex. Endoscopes Blood pressure cuff, Baby weigh scale, Examining table top Decont. level needed Sterilization High-level disinfection (by heat or chemicals) Intermediatelevel or lowlevel disinfection

9 High Level Hydrogen Peroxide Peracetic acid Glutaraldehyde Formaldehyde Intermediate Level Chlorine Iodine Alcohols Low level Phenolics Quaternary Ammonium Compounds

10 production of destructive hydroxyl free radicals that can attack membrane lipids, DNA, and other essential cell components It has been used in concentrations from 3 to 6% for the disinfection of soft contact lenses, tonometer, biprisms, ventilators and endoscopes 6% in 6 Hours is sterilant

11 Very rapid action even in the presence of organic matter Mechanism of action is thought to be similar to other oxidizing agents It is more effective than glutaraldehyde at penetrating organic matter such as biofilms Chemically sterilize medical (e.g., endoscopes, arthroscopes), surgical, and dental instruments

12 This combination has been used for disinfecting hemodialyzers

13 alkylation of sulfhydral, hydroxyl, carboxy, and amino groups of microorganisms, which alters RNA, DNA, and protein synthesis Excellent materials compatibility(non-corrosive) A high-level disinfectant for medical equipment such as Endoscopes spirometry tubing dialyzers, anesthesia and respiratory therapy equipment dialysate delivery systems laparoscopic disposable plastic trocars Respiratory irritation from glutaraldehyde vapour Alkaline solutions require activation (remain active for 2-4 weeks)

14 Used mainly as a gaseous fumigant to disinfect safety cabinets in the laboratory and to fumigate the rooms of patients with highly dangerous pathogens Formaldehyde is a potent eye and nasal irritant and may cause respiratory distress and allergic dermatitis A potential carcinogen Water-based solution called formalin, which is 37% formaldehyde by weight

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16 A combination of iodine and a solubilizing agent or carrier provides a sustained-release reservoir of iodine povidone-iodine bactericidal, mycobactericidal, and virucidal but may require prolonged contact times to kill certain fungi and bacterial spores Alcoholic preparations containing iodine and iodophors are suitable for preoperative skin preparation Povidone iodine detergent preparations are used for surgical hand-disinfection. disruption of protein and nucleic acid structure and synthesis

17 Refers to two water-soluble chemical compounds : ethyl alcohol and isopropyl alcohol Denaturation of proteins lack of sporicidal action + inability to penetrate proteinrich materials Have been used effectively to disinfect oral and rectal thermometers hospital pagers scissors stethoscopes fiberoptic endoscopes external surfaces of equipment [e.g., stethoscopes, ventilators, manual ventilation bags], ultrasound instruments Methyl alcohol (methanol) has the weakest bactericidal action of the alcohols and thus is seldom used in healthcare

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19 Phenol (carbolic acid) is probably the oldest recognized disinfectant Disrupt plasma membranes, inactive enzymes, and denature proteins Active in the presence of organic material Hyperbilirubinemia in infants Phenols are used for environmental disinfection bedside tables, bed rails laboratory surfaces noncritical medical devices

20 generally fungicidal, bactericidal, and virucidal against lipophilic (enveloped) viruses Gram-negative bacilli (e.g. Pseudomonas spp.) may cause contamination and grow in diluted solution Liquid should be stored in closed bottles until immediately before use ( They should not be used in operating theatres)

21 Used exclusively as an antiseptic where contact with skin and mucous membranes is involved pre-operative skin disinfection and with other antiseptics for cleaning dirty wounds