Mod 1 Flashcards
In vivo
Events that occur inside the body
What factors affect microbial growth
Availability of nutrition, moisture, temperatures, PH, osmotic pressure, barometric pressure and composition of the atmosphere
Nutrients
Various chemical compounds that organisms use to sustain life- gases and other elements
Moisture
Cells consist of anywhere between 70% and 95% water
Microorganism that a are commonly on the body are know as what?
Normal flora
What is an optimum growth temperature?
Where the organism grow best
Minimum growth temperature does what?
Ceases the growth
Maximum growth temperature does what?
Causes it to die
What grows best in high temperatures? (Up to 113 degrees C)
Thermophiles
What grows best in normal body temperature? (Plants and animals)
Mesophiles
What grow best in cold temperatures? (Ocean water)
Psychrophiles
A group of psychrophiles known as psychrotrophs grow best where?
In the refrigerator at 4 degrees C
What microbes live in the human stomach?
Acidophiles (Ph 2-5)
Alkaliphiles live where?
Inside the intestines (ph > 8.5)
What is osmotic pressure?
Pressure exerted on a cell membrane by solutions both inside and outside the cell
What is it called when the concentration of solution in the environment outside the cell are greater then the concentration inside the cell?
Hypertonic
What is osmosis?
Is the movement of solvent through a permeable membrane from a solution having lower concentration of solute to a solution having higher concentration of solute
What is the shrinkage of a cell due to loss of water called?
Crenated
What is it called when the concentration of solute outside the cell are less than the concentration inside the cell?
Hypotonic
What is it called when the concentration of solute are equal on the inside and outside?
Isotonic
What microbes prefer the same atmosphere as humans?
Aerobes (20%-21% oxygen and 78%-79% nitrogen)
What microbes require reduced concentrations of O2?
Microaerphiles 5% O2
What are killed by oxygen?
Obligate anaerobes
What does bacterial growth refer to?
Increase in numbers
What is binary fission?
The process of one cell dividing into two cells
What is generation time?
The time it take one cell to become two cells
Under ideal conditions what is the cell generation time of E. Coli, V. cholerae, Staphylococcus and streptococcus?
20 minutes
Under ideal conditions what is the generation time for pseudomonas and clostridium?
10 minutes
Under ideal conditions what is the generation time for mycobacterium and tuberculosis?
18- 24 hours
artificial or synthetic media
Do not occur naturally
Chemically defined medium
All ingredients are know and prepared in the lab
Complex medium
Contents are not known and contains ground up or digested extracts from animal organs, fish, yeast and plants
Enriched medium
Broth or solid contains rich supply of nutrients ( blood and chocolate agar)
Selected media
Are used to grow specific types of bacteria while inhibiting unwanted bacteria
Differential medium
Allows one to readily differentiate among the various types of organisms growing on the medium (MacConkey agar)
What is in inoculation?
Adding a portion of the specimen to the medium
What is incubation?
Appropriate atmosphere and moisture level needed to grow organisms
Sterilization
Destruction or elimination of all microbes (surgical asepsis)
Disinfection
Eliminating most of or all pathogens (except bacterial spores) not used on living tissue
Pasteurization
Kills microbes in wine and eliminates pathogens fro milk
Antiseptic
Disinfects skin, reduces the number of organisms on a surface
Microbistatic agent
Inhibits the reproduction of microorganism
Bacteriostatic agents
Inhibits the metabolism and reproduction of bacteria
Sepsis
Presence of pathogens
Asepsis
Absence of pathogens/free of microbial contaminants
Sporicidal agents
Kills bacteria endospores
Bactericidal
Kills bacteria
Fungicidal agent
Kills fungicides and fungal spores
Anseptic techniques
Eliminating and exclude pathogens by hand hygiene,sterile gloves, mask, gowns.
Antisepsis
Preventing infection
Sterile techniques
Are used to exclude all microorganism
What is dry heat used to sterilize?
Metals, glassware, some powders, oils and wax
What is the most effective type of sterilization?
Moist heat is faster and can be accomplished at lower temperatures
What causes proteins to coagulate?
Moist heat
Autoclave
Is a large metal pressure cooker that destroys all microbial life
In vitro
Events that occur outside the body
What is chemotherapy?
The use of any chemical drug to treat any disease or condition
Antimicrobial agent
Chemicals used to treat an infectious disease either by inviting or killing pathogens without harming the host
What drugs are used to kill bacterial diseases?
Antibacterial agents
What inhibits the growth of bacteria?
Bacteriostatic
What kills bacteria?
Bactericidal agents (penicillin and cephalosporins)
Who discovered penicillin?
Alexander Fleming in 1928
What are antibiotics that have been chemically modified to kill a wider variety of pathogens?
Semisynthetic antibiotics
What is the difference between narrow spectrum antibiotics and broad spectrum?
Narrow kill either gram positive or gram negative and broad kill both
Why are multidrug therapies used?
To simultaneously kill all the pathogens and to prevent resistant Mutant pathogens from emerging - TB requires 4 drugs and up to 12 may be required
What is synergism?
Is the use of more than one drug with more killing power than if the drug was used alone
Antagonism
Is when the use of two drug cause them to work against each other
What drugs are more toxic to the patient?
Antifungal and anti protozoan drugs
How do bacteria become resistant?
Some are naturally because they lack a target site for that drug others because the drug is unable to cross the cell wall (intrinsic resistance) and others because of chromosomal mutations (acquired resistance)
What are two types of b- lactamases
Penicillinases and cephalosporinases
What are strategies in the war on drugs resistance?
Education, prescribe only when warranted, take antibiotics in the manner they are prescribed and do not keep unused antibiotics
Should antibiotics be used for a cold or sore throat?
No because most colds and spare throats are caused by viruses and are unaffected by antibiotics
What is empiric therapy?
When therapy is initiated before lab results are back
What factors should be considered before issuing certain antimicrobial agents?
Allergies, age, pregnant, inpatient or outpatient, is the drug available to the hospital pharmacy, current medical condition, medical history, leukemia or immunocompromised and cost
What are the risk of over use of antibiotics?
The microorganisms can become resistant
