Introduction Mans（介绍芒）.pdfVIP

Introduction Disinfectants used in hospitals and laboratories must be tested periodically to ascertain its potency and efficacy. Evaluation is not for conc. But it is for the activity of the agent under certain conditions and uses Disinfection process validation Defined as: establishing documented evidence that a disinfection process will consistently remove or inactivate known or possible pathogens from inanimate objects. Factors affecting the disinfection process: Effect of temperature; • Bacteriologist Koch had noted that anthrax spore were more readily killed by the same concentrations of phenol if the temperature was elevated. Effect of pH; Any change in PH will affect: • Rate of growth of bacteria growth is optimal at pH (6-8). • Potency of antimicrobial agent due to ionization at pH. • Ability of drugs to combine with cell surface sites of bacteria. Effect of surface activity; • The addition of low concentrations of surface active compounds may potentiate the biological effect of an antibacterial agent. Presence of interfering substances; • The presence of other material may reduce the effect of such an agent by adsorbing or inactivating it and thus reducing the amount available for combining with the cells it is desired to kill. Disinfectant tests • Carrier test • Suspension test • Capacity test • Practical test • In-use test Carrier test Principle: • A carrier such as a silk or catgut thread is contaminated by submersion in a liquid culture of the test organism. • The carrier is then dried and brought in contact with the disinfectant for a given exposure time. • cultured in a nutrient broth; • No growth indicates activity of the disinfectant tested whereas growth indicates a f