Exam 3 Flashcards
Sterilization
Removal or destruction of all microbes
Disinfection
Destroying vegetative cells on inanimate objects; 5% bleach solution
Sanitization
Cleansing technique on inanimate surfaces; public health code
Antiseptic
Chemicals applied to animate surfaces; not as toxic
Degermination
Cleansing procedures used on animare surfaces; implies use of rigor
Germicide
Chemical agents used on animate and inanimate surfaces; target pathogens
Decontamination
Catch-all phrase; destruction, removal, reduction
Thermal death time
Shortest time to kill at a set temperature
Thermal death point
Temperature required to kill in a set time (ex. 10 minutes)
Burning/incineration
Oxidizes all organic material
Steam under pressure
Moist heat
Action: coagulating and permanently denaturing proteins; destroy membranes
Uses: heat resistant material; waste
Drawbacks: powders, oils, moisture repelling materials
Boiling
Uses: disinfection and sanitization
Goal: reduce/kill vegetative cells
Pasteurization
Uses: disinfection and sterilization
Goal: microbial load of pathogens
Types: flash method, ultra-high method
Dry heat
Action: dehydration and oxidation of cell components
Limitations: time and temperature
Uses: powders and oils; glassware and metallic instruments susceptible to rust
Ionizing radiation
Advantages: no heat, very rapid, excellent penetration
Types: cathode rays, gamma rays
Uses: break covalent bonds of DNA, oxidizes other bonds, generate toxic radicals
Nonionizing radiation
Action: create pyrimidine dimers
Drawbacks: poor penetration
Uses: treatment of liquids
Phenols
Actions: denature proteins, disrupt cell walls and membranes, disinfectant, minimal/specific antiseptic
Advantages: -cidal, broad soectrum, active in organic loads, activity over prolonged time
Disadvantages: wont’t destroy spores, toxicity, resistance
Halogens
Fluorine, chlorine, bromine, iodine
Action: strong oxidizers of sulfhydryl bonds on proteins
Chlorine
Disinfectant
Disadvantages: susceptible to organic load, pH, light
Elemental chlorine: large scale water, purification
Chloramines: water purification, antiseptic at low concentrations
Hypochlorites (bleach): broad use, chances of resistance are low
Chlorine oxide: gas disinfection
Iodine
Advantages: less susceptible to organic load, can be mixed with water or alcohol, wound treatment or pre-cleaning
Disadvantages: stain easily, allergies/irritant
Uses: iodophors - complex of iodine with a neutral polymer
Alcohols
Ethanol and isopropyl
Degerming agent
Low intermediate disinfection
Action: concentration has to be greater than 50% but less than 100%, dissolve membranes, coagulate proteins
Advantages: enveloped viruses, nonirritating, cheap
Drawbacks: evaporation, inhalation
Hydrogen peroxide
High level disinfectant
Action: form hydroxyl radicals
Uses: 3% concentration- antiseptic, most common form, not for spores; 35% concentration- vapor and liquid sporicidal, true sterilant
Aldehydes
Cross-link proteins and DNA, shuts down function
Advantages: high potency in organic matter, lab and medical settings, noncorrosive
Disadvantages: high toxicity, basic instability with high pH or temperature
Types: glutaraldehyde (liquid sterilant, carcinogenic), formaldehyde (high-level disinfectant, carcinogenic)
Selective toxicity
Target the microbes not the host, complement host defenses, no cross reactions
Penicillin
B-lactam ring, thiazolidine ring, variable side chain
Mode of action: bacteriocidal, targets logarithmically growing populations
Spectrum of activity: multiple kinds
Penicillin G
Narrow spectrum
Bacteriocidal
Advantages: narrow spectrum > targets G+, low cost, easily reach effective concentration, low toxicity
Disadvantages: resistance (b-lactamase - cuts ring), injection - acid labile so has trouble getting past stomach, allergies
Amoxicillin
Broad spectrum
Kills a lot of gut bacteria (diarrhea, nausea, abdominal pain)
Used most often in children
Great absorption (orally)
Ready distribution
Uses: respiratory infection, ear infection
Extension of use: B-lactamase inhibitors; clavulonic acid > augmentin
Toxicity: rashes, hives, diarrhea or vomiting, increase yeast infections, anaphylactic shock, death
Cephalosporins
B-lactam structure, 2 R groups
Spectrum: -cidal, transpeptidase bonding (broad)
Toxicity: same as penicillin > lower chance of allergies
Admin: injection
Cephalexin (Keflex)
1st gen cephalosporin
Oral administration
Skin/soft tissue infections, UTIs
Cefaclor (Keflor)
2nd generation
Increased resistance to B-lactamase
Injection or orally if fasting
Respiratory, skin/soft tissue, abdominal, gynecological infection
Rocephin (ceftriaxone)
3rd generation
High resistance to B-lactamase
Resistant enterics
Broad spectrum
Can cross blood brain barrier
Cefepime (maxipime)
4th generation
High resistance to B-lactamase
Nosocomial pneumonia
Isoniazid
Synthetic drug Mode of action: prevents synthesis of mycolic acid Very narrow spectrum Administration: orally or injection Combination use: rifampin, streptomycin
Streptomycin
Amino glycosides
Broad spectrum
Mode of action: bind to 16S rRNA; block 1st tRNA
Toxicity: permanent deafness
Uses: tuberculosis, bubonic plague, tularemia
Tetracycline
-static
Broad spectrum
Mode of action: block the A site
Side effects: stain developing teeth, interfere with bone development, interfere with birth control, GI havoc, degrade over time
Uses: penetrate tissues easily, orally, most types of infection
Macrolides - erythromycin
Bacteriostatic except under high doses
Naturally produced
Mode of action: bind to 50S protein and stalls translocation
Can be given orally
Uses: upper respiratory infection, B-lactam sensitivities
Rifampin
Narrow spectrum, Gram positive, acid fast
Mode of action: block RNA polymerase inhibition
Uses: oral or injection, synergism, preventative
Toxicity: minimal, interferes with birth control
Fluoroquinolones and quinolones
Broad spectrum
Target DNA gyrase
Administration: highly absorbed, orally
Uses: UTIs, STDs, GI, soft tissue/skin, respiratory
Side effects: nerve damage, seizures, tendon damage
Cell membrane antibiotics
Mode of action: inserts into membrane
Narrow spectrum
Administration/use: poor absorption; eye, ear, wound
Toxicity: neurons and kidneys
Sulfamides and trimethoprim
Broad spectrum
Mode of action: synergism
Uses: dysentery, UTIs, respiratory, bladder, protozoan infections
Toxicity: allergies
Mechanism 1: limiting access of the antibiotic
- Outer membrane porins: 2 membranes, may allow in through porins into periplasm, don’t allow fully into cell
- Active efflux: in process of hydrolyzing ATP, pump antibiotic out of cell
- Reduced uptake across cytoplasmic membrane
Mechanism 2: enzymatic inactivation of the drugs
- B-lactamases: cut B-lactam rings, now penicillin resistant
- Modifying enzymes: attaches acetyl, phosphoryl, or adenyl groups to drug target, can’t bind
Mechanism 3: modification or protection of target
- Cell wall modification: RNA polymerase and DNA gyrase - point mutation, drug can’t bind
- Ribosome protection
- rRNA methylation: 23S rRNA > erythromycin resistant
- DNA synthesis modification
Mechanism 4: antibiotic tolerance
In log phase, as soon as antibiotic introduced > stationary phase
Stay in stationary phase until drug reduced > back to log phase
Exoenxymes
Mucinase: digests protective coating on mucous membranes
Hyaluronidase: digest hyaluronic acid
Coagulase: causes of clotting in blood and plasma
Exotoxins
Mainly Gram-positive and Gram-negative bacteria
High toxicity
Protein or short peptide
Endotoxin
Gram-negative bacteria
Lipid A
Nonspecific effects
Reticuloendothelial system
Network of connective tissue that forms network between circulatory system and lymphatic systems
Neutrophils
Phagocytosis: digestion, degradative chemicals
Trap pathogens: NETs
Eosinophils
Bone marrow and spleen: highest concentration
Attack and destroy large eukaryotic pathogens
Inflammation and allergic reactions
Phagocytosis occurs but not primary role
Basophils
Allergic reactions: histamine, serotonin, heparin
Inflammation > attract other immune components
Monocytes/macrophage
Long-lived, still multiply, fixed vs transient
Roles: phagocytosis, process and present antigen, communication
Dendritic cells
Type of macrophage
Trap cells/bacteria, move to lymph nodes/spleen for better communication
B cells
Humoral immunity, develop into plasma cell
T cells
Cell-mediated immunity, memory and recognition
TNF
Nonspecific mediator
Increases chemotaxis, phagocytosis, and production of other inflammatory cytokines and fever
Interferon
Inhibits viral replication, turns on other lymphocytes
Interleukins 1 and 2
Activates macrophage, T and B cells
Histamine
Causes vasodilation, increased permeability, and mucous production
Prostaglandins
Inflammatory stimulator
Leukotrienes
Smooth muscle contraction and increased vascular permeability
