unit 11 Flashcards
Sterilization
removal / destruction of all forms of microbial life
-most resistance against endospores
Disinfection
destruction of vegegative pathogens (non endospores)
-applied to fomites
-not sterilization
Antiseptic
chemical disinfection of the skin mucous membranes, living tissue
Asepsis
absence of pathogen from an object/ areaS
Sanitization
reduction of pathogens to safe public health levels
bacteriocydal
to kill bacteria
Bacteriostatic
inhibit growth of bacteria
Moist heat
Boiling /autoclaving
Boiling
100 degrees for 10 minutes
used on dishes , cups, basins
not reliable
why is boiling not reliable
due to bacteria with protective mechanisms
Autoclaving
- used on culture media , equipment , linens
- steam under pressure
- 121 degrees at 15 psi for 15 minutes
-most effective
Pasteurization
- high temp short time (72 degrees / 15 minutes)
- milk cream beer
- not sterilization (to lactobacillus and mycobacterium tb)
- eliminate milk borne pathogens
-lower bacterial counts to prolong the quality of the refrigerated milk
Dry heat
- 100% effective
- direct flame/incineration
- cremation
- hot air (ovens) pipets
Filtration
filters with pores small enough to retain microbes from liquids or gases
- used = vaccines , enzymes , antibiotic solutions
Low temperature (bacteriostatic)
food some meds
Dessication (removes h20 bacteriostatic)
used on foods
freeze dried
hypotonic solutions
Osmotic pressure (hypetonic solutions)
ex= salt brines/ sugar syrups
- food preservation
radiation (non- ionizing)
- long wavelength
-UV light (cant penetrate on surface) - uses = OR room , autopsy room, certain equipment
radiation (ionizing)
- short wave length
- gamma rays
-penetrates surfaces
-replaces gas sterilzation - uses = food, disposables, medical supplies
Zone of inhibition
- clearing around disc that shows no bacterial growth
-used to find most effective antibiotic against a microbe
Chemical methods of control
phenol
halogens
alcohol
heavy metals
surface active agents
quaternary ammounium compounds (quats)
organic compounds
aldehydes
gases
oxidizing agents
phenol
- carbolic acid
- rarely used (caustic /strong odor)
- used in throat lozengers (local anesthetic)
- derivates = phenolics (cresol / lysol)
Hexacholorphene , chlorhexidine, triclosan, and essential oils are example of what chemical agent
phenol
Hexachlorphene
- excessive use can lead to neurological damage
Chlorhexidine
- surgical scrubs
Triclosan
- antibacterial soaps
Halogens
- Iodine ( antiseptic /disinfectant betadine)
- chlorine ( effective disinfectant; bleach)
- combines with water to make hydrochlorous
alcohol
- swabs skin / clean equipment
- kills bacteria/fungi but not endospores/ viruses
- ethanol
- isopropanol or rubbing alcohol
Tincutures of alcohol
- alcohol added to increase effectivness of chemicals
Heavy metals (silver, mercury , copper)
-antiseptic / disinfectant
Surface active agents (soaps, detergents)
-mechanical removal
- emulsifies
Quarternary ammonium compounds (quats)
- antimicrobial/ odorless/ colorless/ tasteless/ non toxic
- uses = mouthwash
- zephiran= benzalkonium chloride
Organic compounds
- sorbic acid / sodium benzoate (cheese/soda)
- sodium nitrate (meats)
What does sodium nitrate do for meat
give its color / preservation
Aldehydes
- most effective antimicrobial agent
- formaldehyde (formatin embalming liquid)
Gases (etheylene oxide)
- high penetrating
-disinfects medical supplies - carcinogenic to workers
Oxidizing agents
-Hydrogen peroxide = antiseptic/ disinfectant
- ozone: disinfection of water
- Benzoyl peroxide = acne medicine
Minimal inhibitory concentration
minimal amount of antibiotics that you distrubute to kill a microbe
effects of combining drugs
synergistic and antagonistic
Synergistic
-most effective way to control microbes
- effects of 2 drugs given together is greater than when given alone
- endocarditis: penicillin (destroys cw)
-streptomycin (enters more easily)
Antagonistic
- drug interference
- drugs interfere with each other
- dont give tetracycline and penicllin together
Synthesis of antibiotics
derived from microbes (bacteria or molds) or chemical synthesized
- 50% from streptomyces sp.
Anti- bacterial antibiotics: mechanisms of action
-metabolic inhibitors
- cell wall inhibitors
- protein synthesis inhibitors
- permeates cell membrane
-inhibition of nucleic acid synthesis
Sulfonamides: sulfa drugs/ trimethoprim (metabolic inhibitors)
- interferes with folic acid synthesis
- folic acid needed to make dna/rna
- resembles PABA (para-aminobenzoic acid)
- uses = UTI/ meningococcal meningtiis)
- limitation = allergic reactions / not effective for sever infections
Isoniazid- inh (metabolic inhibitors)
-inhibits mycolic acid synthesis ( cell wall)
-resembels vitamin B6
- uses= on M. TB
-limitations = resistance / kidney damage
Penicillin (cell wall inhibitor)
- effective against gram + / spirochetes
- natural penicillin = G or V
- extracted from penicillium sp.
-narrow spectrum Antibiotic - limitations = allergies / resistance / narrow spectrum only
Beta lactamase
enzyme that produces new element so it can be resistant to the antibiotic penicillium
what converts penicillin -> penicilloic acid
beta lactamase or penicillinase
Synthetic penicillins: ampicillin , amoxicillin, methicillin (oxacillin) (cell wall inhibitor)
- used on gram +/ gram -
- broad spectrum antibiotics
-overcomes the disadvantages of natural penicillin
Carbapenems (cell wall inhibitor)
- used on pseudomonas sp. / gram - infections
Cephalosporins or cephalothins
- resistant to penicillinase
- effective against gram- / gram +
-broad spectrum antibiotic
Bacitracin (cell wall inhibitor)
- gram + some gram -‘s
-topical cream/ointment - mainly gram +
- from bacillus sp.
Vancomycin (cell wall inhibitor)
- very toxic
-used for MRSA - narrow spectrum antibiotic
- limitations = resistance/ toxicitiy
Protein synthesis inhibitors purpose
targets prokaryotes ribosome’s
Cholramphenicol (protein synthesis inhibitor)
- used for typhoid fever/ meningitis
- broad spectrum antibiotic
-potenitally toxic - limitations= aplastic anemia
Tetracycline (protein synthesis inhibitor)
- less toxic than chloramphenicol
- used on gram+/gram -
- targets ricketsia/chlamydia
- broad spectrum antibiotic
-tissue soluble (Uti’s , RT/GI tract infections)
-limitations = disrupts normal flora , gi problems , tooth discoloration,
-easily diffuses -> tissue
Aminoglycosides (protein synthesis inhibitor)
- all effective against gram -‘s
- broad spectrum antibiotic
- limitations = resistance / auditory nerve damage
Erythromycin: macrolides (protein synthesis inhibitor)
- alternative: penicillin allergic
- used on gram +’s, Legionella , some Neisseria, and Mycoplasma pneumonia
- wont affect most gram -‘s
- given orally (orange flavor)
Purpose of cell membrane permeators
loss of cell metabolites
Polymyxin B (cell membrane permeator)
- used on gram -‘s and pseudomonas
- topical since toxic to kidneys/brain
Polymyxin E: colistin
- used to treat antibiotic resistant bacteria
- last resort
- concern with its use in food animals
Rifamycin or rifampin (inhibition of nucleic acid synthesis)
- inhibits MRNA
- uses on gram +’s and some gram -‘s
- chlamydia, M. lepri, M TB, N, meningitis
- turns urine/ sweat/ feces/ tears orange and red color
Anti-fungal drugs purpose
prevents sterol synthesis in cell membrane
nystatin/ mycostatin, amphotericin B , Imidazoles/ketoconazole , and Griseofulvin are what types of drugs
anti-fungal drugs
nystatin/ mycostatin
used for yeasts
amphotericin B
used for systemic mycoses
Imidazoles/ ketoconazole
used for systemic mycoses
Griseofulvin
used for cutaneous mycoses
Amantadine, Acyclovir, AZT or zidovudine , and Interferon-chronic heptitis are what type of drugs
anti-viral drugs
Amantadine
reduces duration of influenza
Acyclovir
herpes infections
AZT or zidovudine
HIV
Quinine (and its derivatives) and metronidiazole/ flagyl- trichomonas, giardia, entamoeba are what type of drugs
Anti- protozoan drugs (prevents DNA synthesis)
Niclosamide/ mebendazole are what type of drugs
anti-helminthic drugs (prevents atp synthesis/ paralyze helminths)
Niclosamide
used for tapeworm infections
Mebendazole
used for roundworm infections
Development of drug
- enzymatic altercations
- changes in cw/cm permeability
- genetic changes or mutations
- cm proteins that expel antibiotics
