exam 4 pt 1

Sterilization

·       The destruction of all microbial life, including endospores and viruses from an inanimate item

-        Preparation of surgical equipment and of needles used for injection

Pressurized stem (autoclave), chemicals radiation

Disinfection

·       Destroys most microbial life, reducing contamination on inanimate surfaces

-        Through application of heat or antimicrobial chemicals

-        Cleaning surfaces like laboratory benches, clinical surfaces, and bathrooms

Antisepsis

·       Also called degermation is the same as disinfection except a living surface is involved

-        Cleaning skin broken due to injury; cleaning skin before surgery

-        Boric acid, isopropyl alcohol, hydrogen peroxide iodine (betadine)

Decontamination

• Also called sanitization is the mechanical removal of most microbes from an animate or inanimate surface

- Through application of heat or antimicrobial chemicals

- Commercial dishwashing of eating utensils, cleaning public restrooms

- Detergents containing phosphates, industrial-strength cleaners containing quaternary ammonium compounds

Degerming

• Reduces microbial load on skin or tissue through gentle to firm scrubbing and the use of mid chemicals

- Handwashing with soap, alcohol swab

-        Any material that has been subjected to this process is said to be BLANK

-        Sterilized products are essential to human well-being surgical instruments, syringes, commercially packaged foods

sterile

·       The use of a physical process or a chemical agent (blank) to destroy vegetative pathogens but not bacterial endospores

-        blank are normally only used on inanimate objects

Disinfection control

Sepsis

·       The growth of microorganisms in blood and other tissues

Asepsis

·       Any practice that prevents the entry of infectious agents into sterile tissues and prevents infection

Antisepsis

·       application of chemical agents (antiseptics) to exposed body surfaces, wounds, and surgical incisions to destroy or inhibit vegetative pathogens

cidal Agents

chemical agents that kill microorganisms

-static Agents

·       Microbes are prevented from multiplying but are not killed

decontamination is also called

Sanitation

Decontamination is also called

Antisepsis degermation

Death of microscopic Organisms

·       Harder to detect than in macroscopic organisms (no conspicuous vital signs to measure for bacteria)

Effects of agents on the Cell wall

• Agents damages the cell wall by blocking cell wall synthesis, digesting the cell wall, breaking down the surface of the cell wall

The effect of agents on, The cell membrane

-        Disruption of the cell membrane causes loss of selective permeability, loss of viral molecules, and it allows the entry of damaging chemicals

Surfactants

·       Are polar molecules with hydrophilic and hydrophobic regions

Agents that effect, Protein and nucleic, Acid synthesis

-        Agent that impedes the transcription of DNA replication or DNA transcription or changes the genetic code is antimicrobial

Native state

• The normal three-dimensional configuration of a protein that allows proper function

Denature

• Disruption of proteins, rendering them nonfunctional

- Breaking of the bonds that maintain the secondary and tertiary structure

Methods of physical control

·       Heat is the widest used method of microbial control

-        Other methods include radiation, filtration, ultrasonic waves, and cold

Thermal death time

·       The shortest length of time require to kill all test microbes at a specified temperature

Thermal death point

·       The lowest temperature required to kill all microbes in a sample in 10 minutes

Moist heat methods

·       Boiling water: disinfection, Disadvantage is that it can be re-contaminated when removed from the water

Dry heat methods

·       Incineration, the flame of a Bunsen burner reaches the hottest point and incinerates microbes to ashes

Desiccation

Removing moisture from something

lyophilization

• A combination of freezing and drying

- Common method of preserving microbes and other cells in a viable state

Radiation

• Energy emitted from atomic activities and dispersed at high velocity through matter or space

- Blank used for microbial control gamma rays, x rays, ultraviolet radiation

Irradiation

·       Or bombardment with radiation, at the cellular level

-        When a cell is bombarded by certain waves or particles, it leads to two consequences ionizing radiation and nonionizing radiation

Ionizing radiation

·       If the radiation ejects orbital electrons from an atom, it causes ions to form

-        Causes mutations in DNA and damages the proteins that would ordinarily repair it

-        Secondary lethal effects include chemical changes in organelles and the production of toxic substances

Non ionizing radiation

• Ultraviolet UV, excites atoms by raising them to a higher energy state, but it does not ionize them. Excitation, in turn, leads to the formation of abnormal bonds within molecules such as DNA, and that leads to mutations

Effects of UV radiation

• Form pyrimidine dimers which are abnormal linkages on the pyrimidine bases (thymine and cytosine)

Application of filtration

·       Used in liquids that cannot withstand heat, alternative method for decontaminating milk and beer, Important step in water purification

-        Efficient means of removing airborne contaminants

Osmotic pressure

·       Adding large amounts of salt or sugar to foods creates a hypertonic environment

Aqueous

• Solutions containing pure water as the solvent are termed aqueous

Tincture

·       Whereas those dissolved in pure alcohol or water-alcohol

High level germicides

• Kill endospores and if properly used, are sterilant

- Used for catheters, heart-lung equipment and implants

- These devices are not heat-sterilizable and are intended to enter the body tissues during medical procedures

Intermediate level germicides

·       Kill fungal but not bacterial spores, resistant pathogens such as the tubercle bacillus, and viruses

-        They are used to disinfect semi-critical items, respiratory equipment, thermometers

Low levels

• Eliminate only vegetative bacteria, vegetative fugal cells, and some viruses

- Noncritical materials such as electrodes, straps, and pieces of furniture that tough the skin surfaces but not the mucous membranes

Halogens

·       Are fluorine, bromine, chlorine, and iodine, a group of nonmetallic

-        Components of disinfectants and antiseptics

 

Iodine and its compounds

·       in the form free iodine or iodophors

-        all classes of organisms are killed by iodine if proper concentrations and exposure times are used

-        not adversely affected by organic matter and pH

Aqueous iodine

·       Topical antiseptic, treatment for burned and infected skin

Iodine tincture

·       Used in skin antisepsis

Phenol

·       carbolic acid is a poisonous compound derived from the distillation of coal tar

-        first antimicrobial chemical adopted by

Phenolics

·       carbolic acid is a poisonous compound derived from the distillation of coal tar

-        first antimicrobial chemical adopted by joseph lister as surgical germicide, however it has toxic and irritating side effects

Cresols

·       phenolic derivatives combined with soap

Bisphenols

·       Aerosol sprays and cleansing soaps

Triclosan

·       Disinfectant and antiseptic chemical added to many products

Chlorhexidine

·       Hand scrubbing, surgical prep, and other medical uses

-        targets both cell membrane (selective permeability) and protein structure (causing denaturation)

-        for both gram-positive and gram-negative bacteria but inactive against endospores. Effects on viruses and fungi vary

Alcohols

·       colorless hydrocarbons with one or more -oh functional groups

-        only ethyl and isopropyl are suitable for microbial control, methyl alcohol is not suitable

Ethyl alcohol

·       70 to 95%

-        Skin degerming and disinfection of some types of medical equipment

-        Evaporation rate limits effectiveness

Isopropyl alcohol

·       More microbicidal and less expensive than ethanol

-        Evaporation rate also limits efficacy

-        Vapors can adversely affect

surfactants

·       Polar molecules with hydrophilic and hydrophobic regions

-        Physically bind to the lipid layer and penetrate the internal hydrophobic region of membrane

-        This opens up leaky spots that allow damaging chemicals to seep into the cell and important ions to leak out

Quaternary ammonium Compounds (quats)

·       Used for ophthalmic solutions and cosmetics, also used in soap disinfectants: mixed with cleaning agents

-        And they are preservative

-        Weak microbicides because pseudomonas grows abundantly in soap dishes

-        Mainly used for the mechanical removal of microbes, has more of a germicidal effect when mixed with iodine or chlorhexidine

Oligodynamic

• BLANK action means with a force containing one of several inorganic or organic metallic salts. In the form of aqueous, tinctures, ointment, or soap

- Toxic in minute quantities, only mercury and silver compounds have significance as germicides

- Drawbacks are that it is toxic if ingested, causes allergic reactions, neutralized by biological wastes, microbes can develop resistance to it

Weak organic mercury tinctures

·       Effective antiseptics and infection preventives

-        Preservatives in cosmetic and ophthalmic solutions

Application of heavy metal

·       Heavy metals denature proteins, impairing cell function and thus giving them strong antimicrobial properties

-        Copper in fixtures in door handle kill microbes that might accumulate on touched surfaces

-        Eating utensils contain small amounts of silver to inhibit microbial growth

Glutaraldehyde

• Rapid, broad spectrum, accepted as a sterilant

- Retains potency in the presence of organic matter

- Sterilizes materials that could be damaged by heat

Formaldehyde

·       Blank: aqueous solution

-        Intermediate to high level disinfectant

-        Extremely toxic

Blank tincture disinfects surgical instruments and used in aquaculture, active ingredient in embalming

Ortho-phthaladehyde opa

·       Similar to glutaraldehyde less irritating

-        Does not destroy endospores

Ethylene oxide

·       Can be used in a chemicalvae for chemical sterilizations

-        Explosive, carcinogen

-        Causes damage to lunges, eyes, and mucous membranes

• Used for treatment of drinking water, wastewater, food-processing

- Used to disinfect senate offices after the anthrax attacks in 2001

Chlorine dioxide

·       Used for treatment of drinking water, wastewater, food-processing, Used to disinfect senate offices after the anthrax attacks in 2001

Aqueous ammonium oxide

·       Detergents, cleaners, and deodorizers

·       Organic acids used in food preservations

-        Acetic acid propionic acid, lactic acid, benzoic acid, and sorbic acid

Goal of antimicrobial therapy

·       Administer a drug to an infected person that destroys the infective agent without harming the host’s cells

Salvarsan

·       First effective antibiotic came from chemist Paul Ehrlich’s lab, who won a Nobel Prize for it

-        First marketed treatment for syphilis that came from the bacteria, Actinobacteria

Penicillium

• Comes from the fungus penicillium, penicillin was first commercially released during world war 2

- Known as the miracle drug

Origins of antimicrobial drugs

-        Inhibiting the growth of other microorganism in the same habitat reduces competition for nutrients and space

Semisynthetic drugs

·       Drugs that after being produced by bacteria, fungi, or other living sources, are chemically modified in the laboratory

Synthetic drugs

·       An entirely new molecule, manufactured entirely through chemical processes in the laboratory that mimic the actions of antibiotics

Kirby-Bauer technique

·       Is an agar diffusion test that provides useful data on antimicrobial susceptibility

Antibiogram

·       A profile of antimicrobial sensitivity

Etest

·       Another diffusion test which uses a strip to produce the zone of inhibition

-        The advantage of the BLANK is that the strip contains a gradient of drug calibrated in microgram this way,

Minimum inhibitory, Concentration MIC

·       the smallest concentration which is the highest dilution of drug that visibly inhibits growth

-        useful in determine the smallest effective dosage of a drug and in providing a comparative index against other antimicrobials

Therapeutic index TI

Is the defined as the ration of the dose of the drug that is toxic to humans to its effective dose

Selectively toxic

·       They should kill or inhibit microbial cells without simultaneously damaging host tissues

Tetracyclines

·       Bind to the enamel of teeth, causing a permanent gray to brown discoloration, Cause liver damage in pregnant women

-        Cross the placenta and are deposited in fetal bones and teeth

Antimicrobial

• Treats infection

- Destroys normal biota, even those far removed from the original infection

Superinfection

• Beneficial resident species are destroyed through antibiotic therapy

- Microbes once small in number begin to overgrow and cause disease

Broad spectrum drugs

·       Effective against more than one group of bacteria

-        Tetracyclines

Penicillin’s

·       Can be obtained naturally or synthesized in the laboratory

-        Consists of three parts thiazolidine ring, beta lactam ring, variable side chain

penicillin G and V

·       Most important natural forms used to treat gram-positive cocci, some gram-negative bacteria

Ampicillin, carbenicillin, Amoxicillin

·       Have a broad spectrum of action, are semisynthetic; used against gram-negative enteric rods

Penicillinase

·       Or b-lactamases, an enzyme that hydrolyses penicillin; found in penicillin resistant strains of bacteria

Methicillin, nafcillin, cloxacillin

·       Useful in treating infections caused by some penicillinase- producing bacteria (enzymes capable of destroying the beta lactam ring of penicillin)

Clavulanic acid

·       Inhibits beta-lactamase enzymes; added to penicillin’s to increase their effectiveness in the presence of penicillinase-producing bacteria

Cephalosporins

·       Relatively broad-spectrum, resistant to most penicillinases, and cause fewer allergic reactions than penicillins

-        Mostly given orally, many are poorly absorbed from the intestine and must be administered parenterally (injection to muscle or vein)

First generation cephalosporins

·       Cephalosporins such as Cephalothin and cefazolin are most effective against gram-positive cocci and a few gram-negative bacteria

Second generation

·       More effective than first generation against gram-negative bacteria such as Enterobacter, proteus, and haemophilus

Ceftriaxone (Rocephin)

is a semisynthetic broad-spectrum drug for treating a wide variety of respiratory, skin, urinary, and nervous system infections

Cephalexin, cefotaxime

third generation; broad-spectrum, particularly against enteric bacteria that produce beta-lactamases

Ceftobiprole

exhibits activity against methicillin-resistant staphylococcus aureus MRSA and against penicillin resistant gram-positive and gram-negative bacteria

Carbapenem Group of B-lactams

·       New antibiotics such as doripenem and impenem belong to a new class of cell wall antibiotics called carbapenems

-        They are powerful but potentially dangerous and reserved for use in hospitals when other drugs are not working

Aztreonam

narrow- spectrum; used to treat gram-negative aerobic bacilli causing pneumonia, septicemia, and urinary tract infections; effective for those allergic to penicillin

Bacitracin

·       a narrow-spectrum; used to combat superficial skin infections caused by streptococci and staphylococci,

-        main ingredient in Neosporin

Isoniazid

used to treat Mycobacterium tuberculosis, but only against growing cells, used in combination with other drugs in active tuberculosis

Fosfomycin tromethamine

phosphoric acid agent; effective treatment for urinary tract infection caused by enteric bacteria

Aminoglycoside drugs

antibiotics composed of one or more amino sugars and a 6-carbon ring are referred to as aminoglycosides

Streptomycin

·       is among the oldest of the drugs and has gradually been replaced by newer forms with less toxicity, used to treat bubonic plague, tularemia, and tuberculosis