Removing Microbes
moist, works at lower temperature
What does it mean if something is sterile?
There is no life forms present
What can contribute to superinfections?
broad spectrum drugs
What type of antimicrobial is found in Neosporin?
–Which group of antimicrobials are derived from Bacillus polymyxa, toxic to the kidney, treats Pseudomonas aeruginosa and severe UTI and targets the cell membrane
Polymyxins
What is lyophilization?
–A combination of freezing and drying
–Common method of preserving microbes and other cells in a viable state
–Pure cultures are frozen instantaneously and exposed to a vacuum that removes water
What is disinfection?
•The use of a physical process or a chemical agent (disinfectant) to destroy vegetative pathogens but not bacterial endospores.
–Disinfectants are normally only used on inanimate objects
What are narrow and broad spectrum drugs?
narrow target one type, broad - target many types of microbes
What do all the penicillins and cephalosporum have in common?
beta lactam ring
What is the MIC?
smallest concentration (highest dilution) of drug that visibly inhibits growth
minimum inhibitory concentration
What is desiccation?
Removal of moisture by dehydration
The hardest forms of life to kill are ______________________ and the easiest to kill are _____________________.
bacterial endospores; vegetative bacteria and fungi
The cell wall of a microbe can be harmed by the antimicrobial agent by :
digesting it, blocking its synthesis, denaturing proteins
fluroquinolones
What part of the microbes doe rifampin and quinolones target?
nucleic acids, DNA and RNA
What is sanitization? What is antisepsis? How are they different?
Give an example of each
Sanitization-The mechanical removal of most microbes from an animate or inanimate surface
•Antisepsis: Also called degermation. The same as disinfection, but on a living surface
–Salting food
–Smoking food
–Pickling food
–Drying food
–Exposing food, clothing, and bedding to sunlight
What part of the microbe do antimicrobials target?
cell wall, cell membrane, ribosomes, proteins, DNA RNA,
What microbes target protein synthesis?
aminoglycosides (mycin), tetracyclines, glycylcyclines, macrolides (mycin), oxazolidinones (oxytetracycline)
What is the therapeutic index? Is a TI of 20 or 2 better for the patient?
–The ratio of the dose of the drug that is toxic to humans to its minimum effective (therapeutic) dose (MIC)
20 is less risky
Name 4 ways that influence how the microbial agents work.
number of microorganisms
mode and dosage of the agent
temperature and PH
type of microorganism present
This germicide decomposes to toxic O2 gas.
This germicide is typically used to treat water.
hydrogen peroxide
chlorine
What type of microbes do most antimicrobial medications come from?
•Most antibiotics come from bacteria in the genera Streptomyces and Bacillus
•Molds in the genera Penicillium and Cephalosporium
What types of drugs are known to cause problems with developing fetuses and cause discoloration of teeth?
tetracyclines
What are some ways that bacteria become resistant to antimicrobials?
alter drug receptors on cell targets, mutations of chromosomes, prevent drug from entering cells, create enzymes to alter drug