Esterilizacion

Disinfection is the elimination of pathogens, except spores, from inanimate objects

Disinfection

 Disinfectants are chemical solutions used to clean inanimate objects (physical processes, e.g., UV radiation, may also be employed to effect disinfection)  Germicides are chemicals that can be applied to both animate (living) and inanimate objects for the purpose of eliminating pathogens Antiseptics are formulated for application to living tissue

THE IDEAL DISINFECTANT
 Resistant to inactivation

 Broadly active (killing pathogens)
 Not poisonous (or otherwise harmful)

 Penetrating (to pathogens)
 Not damaging to non-living materials  Stable  Easy to work with  Otherwise not unpleasant

DISINFECTANT PERFORMANCE…
 Is dependent on Disinfectant concentrations Is dependent on length (time) of administration  Is dependent on temperature during administration (usual chemical reaction 2x increase in rate with each 10°C increase in temperature)  Microbe type (e.g., mycobacteria, spores, and certain viruses can be very resistant to disinfection—in general vegetative cells in log phase are easiest to kill)  Substrate effects (e.g., high organic contentinterferes with disinfection—stainless steel bench easier to disinfect than turd)  It is easier (and faster) to kill fewer microbes than many microbes

Cleansing is the removal of soil or

CLEANSING

organic material from instruments and equipment & may be done, clinically, in four steps:
 Rinsing the object under cold water  Applying detergent and scrubbing object

 Rinsing the objectunder warm water
 Drying the object prior to sterilization or disinfection

Sterilization is the total elimination of all microorganisms including spores

STERILIZATION

 Typically the last things to die are the highly heat- and chemical-resistant bacterial endospores  Instruments used for invasive procedures must be sterilized prior to use  Moist heat or steam, radiation, chemicals(e.g., glutaraldehyde), and ethylene oxide (a gas) are employed for sterilization  Sterilization by autoclaving, which uses moist heat, is used in most hospital and microbiology laboratory settings

 Sanitization: Lowering of microbial counts to prevent transmission in public setting (e.g., restaurants & public rest rooms)

OTHER TERMS

 Degerming: Mechanical removal of microbes, e.g.,from hands with washing
 Sepsis: Bacterial contamination  Antisepsis: Reduction of or Inhibition of microbes found on living tissue

 Germincides, Fungicides, Virucides
 Physical versus Chemical disinfectants  Static (stasis) versus Cidal (e.g., bacteriostatic versus bacteriocidal)

DIFFERENT KINDS OF BACTERIA “DEATH”
Total cell count

1. Bacteriostatic
Viable cell count

2.Bacteriocidal

3. Bacteriolytic Time

RESISTANCE TO KILLING

 Gram-negative bacteria (with their outer membrane) are generally more resistant than gram-positive bacteria to disinfectants and antiseptics  Stationary-phase (I.e., non-growing) bacteria generally are more resistant than log-phase (I.e., growing) bacteria  Mycobacteria, endospores, and protozoan cysts and oocysts are very resistantto disinfectants and antiseptics  Nonenveloped viruses are generally more resistant than enveloped viruses to disinfectants and antiseptics  Organic matter (such as vomit and feces) frequently affects the actions of chemical control agent  Disinfectant activity is inhibited by cold temperatures  Longer application times are preferable to shorter  Higher concentrations, though, are not alwayspreferable to lower concentration (e.g., alcohols)

Agent

Mechanisms of Action Membrane Disruption; increased penetration Denature proteins; Disrupts lipids High/low pH Denature protein Oxidizing agent Disrupts cell membrane Denatures proteins; Disrupts lipids Disrupts cell membrane

Comments Soaps; detergents Antiseptic - benzalconium chloride, Cepacol; Disinfectant Mold and Fungi...