129 terms

Microbiology Ch.9

the destruction of all microbes, including Bacteria, Viruses, and Endospores in or on an object - but NOT Prions
environment or procedure free of pathogens
use of Physical or Chemical Agents to destroy microorganisms, especially pathogens, on NONLIVING objects
use of Chemical Agents to destroy microorganisms on SKIN or MUCOUS MEMBRANES of the body
removing microbes from a surface by scrubbing (washing hands; preparing area of skin for an injection)
Which are milder; Antiseptics or Disinfectants?
the process of disinfecting public areas or utensils used in public place to reduce the number of pathogens to meet accepted Public Health Standards
use of heat to kill pathogens and most spoilage organisms in food and beverages without altering the quality of the food
Bacteriostatic, Fungistatic, Virustatic
Chemical or Physical Agents that inhibit metabolism and growth of Bacteria, Fungi, and Viruses respectively, but do not necessarily kill or inactivate them
Bactericide, Fungicide, Virucide
agents that kill or permanently inactivate Bacteria, Fungi, and Viruses, respectively
chemical agent that destroys pathogenic microbes in general
How Antimicrobial Agents kill microbes
By altering their cell walls or cytoplasmic membranes; or by interfering with their metabolism and reproduction by damaging proteins and nucleic acids
Cell wall
what maintains the integrity of the cell and ,when disrupted, cannot prevent the cell from bursting due to Osmotic Effects?
Cytoplasmic membrane
What, when damaged, causes cellular contents to leak out?
Viral Envelope
What is responsible for the attachment of the virus to a target cell?
Viral Replication
Damage to the Viral Envelope interrupts what?
Nonenveloped viruses
Which have a greater tolerance of harsh conditions; Enveloped Viruses or Nonenveloped Viruses?
its 3-D shape
What does protein function depend on?
Denature proteins
Extreme heat, or certain chemicals do what to proteins?
Chemicals, Radiation, and Heat
What 3 things can alter or destroy Nucleic Acids?
Chemicals, Radiation, and Heat altering or destroying Nucleic Acids
What can produce Fatal Mutations and can halt protein synthesis through action on RNA?
humans, animals, and objects
Agents used for Microbial Control should control all microbial growth while being harmless to ______, ______, and _______.
Factors affecting the efficacy of antimicrobial methods
Includes: The nature of the site to be treated, the degree of susceptibility of microbes involved, and environmental conditions that pertain
Harsh chemicals and extreme heat
When taking into consideration the site to be treated by antimicrobial methods, one must take into account the fact that ______ ________ and ________ _____ cannot be used on humans, animals, and fragile objects.
Enveloped viruses, Gram-positive bacteria, Nonenveloped viruses, Fungi, Gram-negative bacteria
Place these types of microorganisms in order from most susceptible to most resistant: Fungi, Gram-positive bacteria, enveloped viruses, Gram-negative bacteria, and nonenveloped viruses
Gram-negative bacteria, Active stage protozoa (trophozoites), Cysts of protozoa, Mycobacteria, Bacterial endospores
Place these types of microorganisms in order from most susceptible to most resistant: Mycobacteria, Active stage protozoa (trophozoites), Bacterial endospores, Gram-negative bacteria, and Cysts of Protozoa
High-level germicides
kill all pathogens, including Endospores
High-level germicides
used to sterilize invasive instruments (catheters, implants, and parts of heart-lung machines)
Intermediate-level germicides
kill Fungal Spores, Protozoan cysts, viruses and pathogenic bacteria
Intermediate-level germicides
used to disinfect noninvasive instruments in contact with mucous membranes (endoscopes and respiratory equipment)
Low-level germicides
kill vegetative bacteria, Fungi, Protozoa, and some Viruses
Low-level germicides
used to disinfect objects only in contact with skin (electrodes and furniture)
Acidic conditions
What enhance antimicrobial effects of heat and some chemical disinfectants?
Sodium Hypochlorite
household chlorine bleach (example of acidic conditions enhancing antimicrobial effects of a chemical disinfectant)
body materials
What can reduce the effectiveness of heat, disinfectants, and some forms of radiation?
Phenol Coefficient, Use-dilution test, and In-use test
What are the 3 methods for evaluating disinfectants and antiseptics?
Phenol Coefficient
What test is used for evaluating the efficacy of disinfectants and antiseptics by determining the ratio of the agent's ability to control microbes to that of Phenol?
Use-dilution test
What test involves Metal cylinders being dipped into broth cultures of bacteria and dried, immersed into dilutions of disinfectants for 10 minutes, removed, washed, and placed into a tube of medium for 48 hours?
In the Use-dilution test, the most effective agent entirely prevents microbial growth at the _________ dilution.
In-Use test
What test involves swabs being taken from objects before and after the application of Disinfectant or Antiseptic and inoculated into growth medium, which is then monitored for microbial growth?
In-Use test
What test gives an accurate determination of the proper strength and application procedure for each specific situation?
Exposure to extremes of Heat, exposure to extremes of cold, desiccation, filtration, osmotic pressure, and radiation
What are the 6 physical methods of microbial control (in the order they are listed in our notes)?
Effects of high temperatures
Denaturation of proteins, interference with the integrity of cytoplasmic membranes and cell walls, and disruption of the structure and function of nucleic acids
Thermal Death Point
the lowest temperature that kills all cells in a broth in 10 minutes
Thermal Death Time
the time to sterilize a volume of liquid at a set temperature
Moist Heat
Used to disinfect, sanitize, and sterilize. Kills by denaturing proteins and destroying cytoplasmic membranes, and is more effective than dry heat.
Boiling, Autoclaving, Pasteurization, and Ultrahigh-Temperature Sterilization
What are the 4 methods of microbial control using moist heat?
Vegetative cells of bacteria and fungi, protozoan trophozoites, and most viruses within 10 minutes at sea level
What does Boiling kill?
Water boils at _________ temperatures at higher elevations.
Endospores, Protozoan cysts, and some viruses
What can survive boiling?
What method using moist heat uses pressure applied to boiling water, which prevents steam from escaping, allowing temperatures to rise exceed 100 degrees celcius at sea level?
Boiling temperature __________ as pressure increases.
what is the moist heat method used today for milk, ice cream, yogurt, and fruit juices that is NOT sterilization, because is allows Heat-tolerant (Thermoduric) and Heat-loving (Thermophilic) microbes to survive?
Thermoduric and Thermophilic microbes
What microbes are able to survive pasteurizatioin, do not cause spoilage prior to consumption, and are generally not pathogenic?
Batch Method, Flash Pasteurization, and Ultrahigh-Temperature Pasteurization
What are the 3 methods of pasteurization used on milk?
Batch method
What pasteurization method requires 30 minutes at 63 degrees Celcius?
Flash Pasteurization
What pasteurization method requires a temperature of 72 degrees celcius for 15 seconds (milk is run through heated tubes, effectively destroying all pathogens)?
Ultrahigh-temperature pasteurization
What pasteurization method requires a temperature of 134 degrees Celcius for 1 second?
Ultrahigh-Temperature Sterilization
What moist heat method involves exposing milk and other liquids to superheated steam at 140 degrees celcius for 1-3 seconds, then rapid cooling?
all living microbes
What does Ultrahigh-temperature sterilization kill?
room temperature
At what temperature can liquids treated with Ultrahigh-temperature sterilization be stored?
Dry heat
What is used for materials that cannot be sterilized with or are damaged by moist heat?
Denatures proteins and oxidizes metabolic and structural chemicals
What does dry heat do?
higher temperatures for longer time
What does dry heat require in comparison to moist heat?
ultimate means of sterilization
Decrease microbial metabolism, growth, and reproduction
What do refrigeration and freezing do?
Psychrophilic microbes
What kind of microbes can multiply in refrigerated foods?
halts growth
Refrigeration _____ ______ of most pathogens.
Slow freezing
Which is more effective; slow freezing or quick freezing?
________ inhibits growth due to the removal of water, only MICROBIOSTATIC.
instant freezing in liquid nitrogen; then exposure to vacuum for water removal-- used for long term preservation of microbial cultures
prevents the formation of damaging ice crystals
Cells in a __________ solution of salt or sugar lose water; cell desiccates
Which have a greater ability to survive Hypertonic environments; Bacteria or Fungi?
Shorter Wavelength Radiation
radiation that has more energy and greater penetration
effects on cellular chemicals
Radiation is Ionizing or Nonionizing according to their _____ __ ________ ________.
Which has shorter wavelength; Ionizing or nonionizing?
Which has longer wavelength; Ionizing or nonionizing?
Ionizing radiation
wavelengths shorter than 1 nm, and includes Electron beams, Gamma Rays, and X Rays
Ionizing radiation
eject electrons from atoms to create Ions
disrupt Hydrogen bonding, Oxidize double covalent bonds, and create Hydroxide Ions; Hydroxide ions denature other molecules (DNA)
Electron beams
form of radiation effective at killing, but do not penetrate well
Electron beams
used to sterilize spices, meats, microbiological plastic ware, and medical and dental supplies
Gamma Rays
form of radiation that penetrate well, but require hours to kill microbes
Gamma Rays
used to sterilize meats, spices, and fresh fruits and vegetables
X Rays
form of radiation that require too much time to be practical for growth control
Nonionizing radiation
excites electrons and causes them to make new covalent bonds, which affects the 3-D structure of Proteins and Nucleic acids
UV light
causes the formation of pyrimidine dimers in DNA and does not penetrate well
UV light
suitable for disinfecting air, transparent fluids, and surfaces of objects
Chemical methods of microbial control
affect microbes' cell walls, cytoplasmic membranes, proteins, or DNA
temperature, length of exposure, the amount of organic matter, pH, concentration, and the age of the chemical
The effect of chemical methods of microbial growth varies with what?
Chemical methods of microbial control
tend to be more effective against enveloped viruses and vegetative cells of bacteria, fungi, and protozoa
Phenols, Alcohols, Halogens, Oxidizing Agents, Surfactants, Heavy Metals, Aldehydes, Gaseous Agents, and Antimicrobics
What are the 9 major categories of chemical methods of microbial control (in the order their listed in the notes)?
Intermediate to Low-Level Disinfectants
What are level are Phenol and Phenolics?
Denature Proteins and disrupt Cell membranes
What do Phenol and Phenolics do to cells?
Phenol and Phenolics
effective in the presence of organic matter and remain active for a prolonged time
health care settings, labs, and homes
Where are Phenol and Phenolics commonly used?
Intermediate-Level Disinfectants
What level are Alcohols?
Denature proteins and disrupt Cell membranes
What do Alcohols do to cells?
Intermediate-Level Antimicrobial Chemicals
What level are Halogens?
Believed that they damage Enzymes via Oxidation or by Denaturing them
Oxidizing Agents
Peroxides, Ozone, and Peracetic Acid
Peroxides, Ozone, and Peracetic Acid
Oxidizing agents that kill by oxidation of microbial Enzymes
High-Level Disinfectants and Antiseptics
What level are Oxidizing Agents?
Hydrogen Peroxide
Oxidizing agent that can disinfect and sterilize surfaces of objects
neutralizes, but is not useful for treating open wounds
Oxidizing agent for the treatment of drinking water
Peracetic Acid
effective Sporocide used to sterilize equipment--since it's not adversely affected by organic contaminants and leaves no toxic residue
"Surface active" chemicals that reduce Surface Tension of solvents to make them more effective at dissolving solutes
Have Hydrophilic and Hydrophobic ends; good Degerming agents, but not Antimicrobial
positively charged Organic Surfactants, and more soluble in water than soaps
colorless, tasteless, harmless to humans, and Antimicrobial; ideal for many medical and industrial applications
Low-Level Disinfectants
What level are Quats?
are Antimicrobial because they alter the 3-D shape of Proteins, inhibiting or eliminating their function
Heavy Metals
Low-Level Bacteristatic and Fungistatic Agents
1% Silver Nitrate
What is used to prevent blindness caused by N. gonorrhoeae?
Heavy metal used to preserve vaccines
Heavy metal which controls algal growth in reservoirs, fish tanks, swimming pools, and water storage tanks; interferes with chlorophyll
Compounds containing terminal -CHO groups
Cross-link with Amino, Hydroxyl, Sulfhydryl, and Carboxyl groups to denature Proteins and inactivate Nucleic Acids
both disinfects (with short exposure) and sterilized (with long exposure)
used in embalming and disinfection of rooms and instruments
Ethylene Oxide, Propylene Oxide, and Beta-Propiolactone
What are 3 Gaseous Agents that are used in closed chambers to sterilize items?
Gaseous Agents
Denature Proteins and DNA by cross-linking Functional Groups
Gaseous Agents
used in hospitals and dental offices
Gaseous Agents
Can be hazardous to people, often highly explosive, extremely poisonous, and are potentially Carcinogenic
Include Antibiotics, semisynthetic, and synthetic chemicals
treatment of disease
What are Antimicrobials typically used for?
other than for the treatment of diseases, some of these are used for antimicrobial control outside the body