LP5 Infection Control Flashcards
Antimicrobial Agent
A chemotherapeutic agent used to treat diseases caused by microbes.
What growth represents logarithmic growth of bacteria?
Log phase- second of four major phases of growth, in which cells divide at an exponential or logarithmic rate.
Microorganism or Microbe
Any organism studied with a microscope; bacteria, fungi, parasite or virus.
Sterilization
The killing or removal of all microorganisms in a material or on an object.
Disinfection
Reducing the number of pathogenic organisms on objects or in materials so that they pose no threat of disease.
Antiseptics
A chemical agent that can be safely used externally on tissue to destroy microorganisms or to inhibit their growth.
Medical asepsis prevents 2 things?
1) Prevents the contamination of patients, fomites, environment and healthcare providers and 2) Prevents and reduces nosocomial infections
Factors affecting Chemical Antimicrobial Agents?
1) time of exposure-need adequate time of exposure to antimicrobial 2) Temperature- can increase time/decrease temperature as needed to kill organism 3) pH- increases/decreases the potency of the agent 4) Concentration- increases/decreases the effects of the agent
Mechanisms of destruction for viruses using an antimicrobial agent?
1) Inhibit nucleic acid synthesis by host cell 2) Inhibit protein synthesis by host cell 3) Prevent absorption and penetration during viral replication process
Mechanisms of destruction for Bacteria, Parasites and Fungi using an antimicrobial agent?
1) Inhibit protein synthesis 2) Destroy cell membrane 3) Inhibit nucleic acid synthesis 4) Destroy cell wall 5) Inhibit metabolic capabilities
What effect does oxidizing agents have on microbes?
1) Denature proteins and disrupts disulfide bonds (i.e. 3% Hydrogen Peroxide) 2) Kills organisms except those with catalase (S. aureus), which breaks down H2O2 to H2O + O2-produces oxygen when broken down 3) Kills obligate anaerobes
What effect does moist heat have on microbes?
1) Denatures proteins 2) Penetrates materials quickly 3) Boiling- 100 C kills most bacteria, fungi and viruses but NOT ENDOSPORES 3) Autoclave- 15# pressure, 121 C, 15 min destroys all vegetative and dormant forms of microbes, including Endospores.
Pasteurization
1) Denatures protein 2) Does NOT STERILIZE but reduces the possibility of microbial contamination (i.e. Milk- extends shelf-life) 2) 72 C for 15 sec or 63 C for 30 min
What effect does refrigeration have on microbes?
1) Slows down enzyme activity 2) Temps 0-5 C 3) Does NOT STERILIZE but reduces or inhibits microbial growth 4) Short duration of effectiveness 5) If items are kept too long they begin to grow a “velvety coat”
What effect does dry heat have on microbes?
1) Destruction via oxidizing molecules that denature proteins 2) penetrates slowly 3) longer exposure time needed to be effective (171 C-1hr, 160C-2 hrs., 121 C 16 hrs.) Examples: Oven, incinerator or open flame
What effect does freeze drying have on microbes?
1) Inhibits enzyme activity 2) Drying of microorganisms from a frozen state 3) Drying takes place under high vacuum which only removes water 4) Organisms can remain VIABLE in this state for many years 5) Used to preserve microorganisms ATCC
What effect does radiation have on microbes?
1) Affects microbes nucleic acid thus impairing microbial functions 2) Denatures proteins 3) Used in biological hoods and surgical fields in healthcare 4) Microwave ovens can kill microorganisms however ENDOSPORES ARE NOT- contain little water
What effect does filtration have on microbes?
1) Mechanically removes microorganisms 2) Requires filters with very small pores (0.2 and 0.45 micron filters) 3) High Efficiency Particulate Air Filters (HEPA) used in health care ventilation systems trap organisms in the air 4) Filters need to be disinfected prior to disposal.
