Goal
Skin can't be sterilised
Purpose
- remove transient & pathological bugs
- reduce resident flora to low level
- antiseptic agents effectively eliminate bacterial count at the operative site
- recolonization begins within 30 minutes from hair follicles
Types
Chlorhexidine
Iodine
Povidine - Iodine
Alcohol
1. Chlorhexidine
Action
- disrupts cell membranes
- bactericidal & virucidal
- gram positive > gram negative
Advantage
- good residual effect as binds to protein in Stratum Corneum
- less inactivation by organic material than iodine
- occasional allergy
Disadvantage
- slow onset of effect
- cationic molecule which is incompatible with soaps & other anionic materials
- poor against spores & fungus
Types
Skin Preparation
- 0.5% Chlorhexidine Gluconate in 70% alcohol
Surgical Scrub
- 5% Chlorhexidine Gluconate ç lathering agent
2. Iodine
Advantage
- effective against gram positiv / negative / viruses / funguses
- sporicidal after prolonged contact
Disadvantage
- poor residual activity
- high incidence of skin sensitivity reactions
- toxic to osteoblasts, fibroblasts & keratinocytes
- inactivated by organic material
- an anion so incompatible with cations / chlorhexidine
Skin preparation
Weak Iodine - 2.5% I in 70% alcohol
Tincture - 2.5% I + 2.5% K+ I-
3. Povidine- Iodine
Structure
- Iodine +
- Povidine (Polyvinyl-Pyrrol-Idone)
Advantage
- bactercidal & fungicidal
- gram positive > gram negative
- slowly sporicidal
- introduced to decrease irritative effect
- decreased skin sensitivity reactions
Skin preparation - Betadine
10% aqueous solution
10% in 30% or 70% alcohol
Scrub 7.5% Povidine Iodine with Soaps
4. Alcohol
Advantage
- bactericidal, fungicidal, virucidal
- gram positive and negative
- destroys 90% of skin microbes in 2 minutes
- increases the efficacy of other antiseptics when used concomitantly
Disadvantage
- doesn't destroy spores
- activity drops below 50% concentrations
- rapid activity, but not sustained
- inadequate alone
Results
Skin Preparation
Daroulche et al N Eng J Med 2010
- RCT of alcholic chlorhexidine v povidone-iodine
- alcholic chlorhexidine significantly reduced superficial and deep infections
Hand washing
Tanner et al Cochrane Database Review 2008
- alcohol rub at least if not more effective in decreasing CFU's than aqueous scrub
- chlorhexidine aqueous scrub more effective than povidone-iodine aqueous scrubs
Summary
|
|
Chlorhexidine |
Iodine |
Povidine Iodine |
Alcohol |
|
General |
Cationic
Disrupts cell membrane |
|
Iodine complexed with anionic detergent |
Denatures proteins 90% microbes within 2 min Activity decreases below 50% |
|
Presentation |
Skin prep - 0.5% chlorhex gluconate with 70% alcohol Aqueous hand scrub - 5% chlorhex gluconate |
2.5% iodine in 70% alcohol |
Skin prep - 10% aqueous - 10% in 30 / 70% alcohol Surgical scrub 7.5% |
|
|
Efficacy |
Gram pos > gram neg Bactericidal Viricidal
No spores / fungal |
Gram pos = gram neg Bactericidal Viricidal Fungicidal
Sporicidal with prolonged contact |
Gram pos > gram neg Bactericidal Viricidal Fungicidal
Slowly sporicidal |
Gram pos = gram neg Bactericidal Viricidal Fungicidal
no spores |
|
Clinical |
Skin contact 2 min Residual effect- binds to stratum corneum occ allergy |
Poor residual activity Percutaneous absorption |
Variable residual Min skin absorption Decreased skin sensitivity Decreased irritative effect |
Rapid action
Not sustained De-fat action Desiccates skin |