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83 Cards in this Set
- Front
- Back
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Ehrlich
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- 1907
- arsenical against Treponema |
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Fleming
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1928
- Penicillum mold and Staph |
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Domagk
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1935
- sulfonamide and strep |
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1940-50
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Penicillin, strep, tetracyclines
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1950-70
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new penicillins, aminoglycosides
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1970-90
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cephalosporins, quionolones (used on malaria)
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1990-
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fluoroquinolones, very few new drugs
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bactericidal
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kills bacteria
- penicillin |
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bacteriostatic
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inhibits growth
- once bacteria stop increasing, the immune system can do the work - tetracyclines - use in non- immunocompromised p |
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narrow spectrum
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1. bacitracin
2. penicillin G |
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broad spectrum
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tetracyclines
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grouping
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based on mechanism of action
- eg cell wall inhibitors such as penicillin |
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aim
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maintain effective concentration at the infection site
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choice
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1. diagnosis
2. susceptibility of causal agent 3. nature of infection ( local, systemic) 4. pharmacokinetics 5. host sp, age, pregnancy |
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dosage
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3-5x MIC (minimal inhibitory conc) required at site
- MIC: lowest dose which inhibits growth in vitro |
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routes
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- PO, IV, IM/ SQ
- local (eye/ear) |
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diagnosis and susceptibility of causal agent
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- diagnosis and susceptibility of causal agent
eg strangles in horse caused by Streptococcus equi normally responds to penicillin |
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nature of infection
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- lung, urinary tract
- drug is systemically administered - should reach active concentration in the infection site |
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host sp, age and pregnancy
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baby rabbit with pyoderma:
- pen group of drugs can cause fatal enteritis and death of rabbits - avoid cephalosporins and penicillins |
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effective dose
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- dose should result in 3-5 x MIC at infection site
- oral route is suitable for drugs which are not destroyed in the stomach, unlike Pen G - Aminoglycosides (gentamycin) not absorbed in the GI) |
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Long-acting drugs
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- long- acting drugs, such as liquamycin -LA, are administered by IM injection in cattle to treat pink eye caused by Moraxella bovis
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inhibition of cell wall sythesis
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inhibition of cell wall sythesis:
1. penicillins 2. cephalosporins |
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damage to cell membrane function
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damage to cell membrane function:
- polymyxins - only topical because toxic to cell membrane |
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inhibition of nucleic acid synthesis or function
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inhibition of nucleic acid synthesis or function:
1. sulfonamides 2. quinolones - enrofloxacin |
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inhibition of protein synthesis
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inhibition of protein synthesis (ribosomes):
1. tetracyclines 2. aminoglycosides |
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resistance mechanisms
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1. production of enzymes that destroy or inactivate drug
2. alteration of target site 3. reduction of bacterial cell permeability 4. development of alternative metabolic pathway |
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production of enzymes that destroy or inactivate drug
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production of enzymes that destroy or inactivate drug:
eg drug resistant Staph aureus produces beta lactamase which inactivates penicillin by detroying the beta lactam ring |
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major groups
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1. beta lactam: pen, cephalosporins
2. tetracyclines: doxycycline 3. aminoglycosides: gentamycin 4. macrolides: erythromycin 5. sulfonamide- trimethoprim 6. fluroquinolones: enrofloxacin |
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beta lactams examples
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1. pen G: strep, coryne to treat strang;es
2. ampicillin, amoxycillin: strep, some (-) to treat respiratory infections 3. clavamox: B lactamase producers, better, anaerobes 4. cefadroxil, ceftiofur: 3rd gen, pseudomonas |
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tetracycline example
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tetracycline:
- Brucella, mycoplasma - use in: rickettsia, chlamydia |
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aminoglycosides example
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aminoglycosides:
- gentamycin: pseudomonas - use in: otitis externa |
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sulfa and trimethoprim example
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sulfa and trimethoprim:
- E coli, Bordatella - use in: UTI, respiratory infections |
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fluoroquinolones example
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fluoroquinolones:
- G + and -, Pseudomonas - use in: UTI, respiratory infections |
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macrolides example
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macrolides:
- Erythromycin: Campylobacter - use in: Campy diarrhea |
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Penicillins
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penicillins are beta lactams
- narrow spectrum: Pen G - broad spectrum: ampicillin - susceptible organisms: 1. Pen G: Corynebacterium, Streptococcus 2. other: Erysipelothrix, Clostridium |
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Potentiated penicillins
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- beta lactams
- antibiotic with other agent: more effective 1. Ampicillin + Sulbacatam which inactivates beta lactamase of bacteria 2. Amoxicillin + Clavalanic acid |
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Beta lactam
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- potentiated penicillins include chemicals, such as sublacatam, which inactivates beta lactamase of bacteria
- beta lactamase inactivates beta lactam drugs, including amoxycillin |
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amoxicillin
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amoxicilin:
- broad spectrum including anerobes (not Pseudomonas, mycoplasma) - suspectible to beta lactamase + clavulanic acid (potentiated) resists beta lactamase |
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cephalosporins
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cephalosporins:
- 1st gen: cephalothin, cefadroxil, somewhat narrow spectrum, mainly + - 3rd gen: ceftiofur, broad spectrum, respiratory horse, BRD cattle |
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tetracyclines action
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tetracyclines:
- broad spectrum: +/- including Brucells, mycoplasma, Chlamydia - resistance common among enteric bacteria - destory intestinal flora, problem if used long term |
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tetracyline products
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1. oxytetracycline: cattle
2. doxycycline: dogs |
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avian chlamdydiosis
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- Chlamydophila psittaci
- tetracyclines effective - imported birds: quaratine, prophylactic in feed - subclinical infection common in dom and wild birds - loss of condition, nasal and ocular discharge, diarrhea respiratory distress |
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Chlamdyophila felis conjunctivitis
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Chlamdyophila felis conjunctivitis:
- acute, chronic or recurrent - zoonotic infection: flulike, chronic cough - tetracycline effective |
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Feline mycoplasmoses
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Feline mycoplasmoses:
- conjunctivitis in cat - tetracyline effective |
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Ehrlichia
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Ehrlichia:
1. canis: canine monocytic erlichiosis, worldwide 2. ewingii: canine granulocytic erlichiosis, USA - both host dogs and ticks, tetracycline effective |
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Rickettssia ricketsii
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Rickettssia ricketsii:
- host: dog, human, ticks - rocky mountain spotted fever - Americas - oxytetracycline |
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Neorickettsia helminthoeca
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Neorickettsia helminthoeca:
- hosts: dog, fish with flukes - salmon poisoning disease (fluke involved): fever, vomiting, diarrhea - Western US - oxytetracycline |
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oxytetracyline
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oxytetracyline:
- long activity: up to 5 days with a single injection - LA (long acting): pink eye in cattle, given as single IM inj |
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aminoglycoside products
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aminoglycoside:
1. streptomycin: oldest, resistance common 2. neomycin: better than strepto 3. kanamycin: slightly better than neo 4. gentamycin: better than all above, esp for G- including Pseudomonas aeruginosa 5. amikacin, tobramycin: better than gentamycin, incl Pseudomonas |
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Gentamycin
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gentamycin: aminoglycoside
- effective against many G- bacteria including Pseudomonas aeruginosa - topical application in canine and feline otitis externa |
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Macrolides
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macrolides:
1. Erythromycin: G+ mainly (strep, staph), Campy, Lepto 2. Tylosin: G+, Mycoplasma 3. Tiamulin: swine eg Actinobacillus pleuropneumoniae, Brachyspira hyodysenteriae 4. Tilmicosin: Bovine resp dis (Pasteurella) |
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Erythromycin
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erythromycin is a macrolide
- used in combination with rifampin to treat Rhodococcus equi pneumonia in horses |
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Sulfonamide + trimethoprim
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Sulfonamide + trimethoprim:
- gen broad spectrum: E coli, salmonella, Nocardia - not Campy, Pseudomonas - UTI in dogs: high conc in urine - respiratory infections - small and large animals |
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Quinolones
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quinolones:
1. older: nalidixic acid, narrow spectrum 2. fluoro: cipro, enrofloxacin |
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fluoroquinolones gen
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fluoroquinolones:
- floxacins - broad spectrum: + and - - no anaerobe activity - good distribution in tissues: UT, RT, bone, skin |
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ciprofloxacin
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ciprofloxacin:
- fluoroquinolone - derivative of enro - used mainly in humans |
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enrofloxacin, orbifloxacin
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enrofloxacin, orbifloxacin:
- fluroquinolones= broad spectrum, not anaerobes - dogs: enrofloxacin (baytril) for UTI, RTI, pyoderma + silver sulfadiazine for otitis externa cause by Pseudomonas aeruginosa - birds, reptiles |
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Bacitracin
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bacitracin:
- narrow: G (+) - topical application: BNP |
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Polymyxin
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polymyxin:
- G(-) including Pseudomonas - topical: BNP - ear preparations |
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vancomycin
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vancomycin:
- G (+) - mainly human use |
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Clindamycin, metronidazole
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Clindamycin, metronidazole:
- anaerobes |
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Chlormaphenicol
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Chloramphenicol:
- broad activity - limited use |
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Florfenicol
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florfenicol:
- analog of chloramphenicol - used in cattle for BRD (Pasteurella, Mannheimia) |
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Rifampin
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rifampin:
- Mycobacterium - Rhodococcus equi |
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Antibiotic susceptibility testing via broth dilution
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Antibiotic susceptibility testing via broth dilution:
-gives minimal inhibitory concentration (MIC) of drug |
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Antibiotic susceptibility testing
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Antibiotic susceptibility testing:
1. broth dilution 2. Kirby- Bauer 3. E test - no need in Corynebacterium, Erysipelothrix, Bacillus |
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Kirby-Bauer disc diffusion
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Kirby-Bauer disc diffusion:
- widely used susceptibility - zones measured and interpreted using a standard chart: 1. sensitive 2. intermediate 3. resistant |
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E test
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E test:
- susceptibility test - gives MIC: intersection between growth zone and strip - used in special cases |
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sterilization physical agents
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sterilization physical agents:
1. moist heat 2. dry heat: glassware 3. radiation/ UV 4. filtration |
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moist heat
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moist heat:
- boiling: spores survive - autoclaving |
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radiation/ UV
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radiation/ UV:
- theaters and inoculating hoods - ionizing radiation/ gamma rays for catheters - plastic petri dishes: inactivates spores |
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filtration
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filtration:
- serum, injectible solutions - Mycoplasma will pass through |
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Chemical sterilization
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Chemical sterilization:
1. properties: kills spores, acts fast and in organic matter, low T, wide pH range, non-toxic, stable 2. phenol coefficient: PC 40= 40x killing power compared to phenol |
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chemical sterilization agents
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Chemical sterilization agents:
1. soluble alcohols 2. sterilizing gas 3. disinfectant gas 4. glutaldehyde 5. halogens 6. phenolics 7. detergents |
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soluble alcohols
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soluble alcohols:
rapidly bactercidal -S |
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sterilizing gas
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sterilzing gas:
- ethylene oxide: limited use - some S - 4-18 h required |
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disinfectant gas
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disinfectant gas:
- formaldehyde + S - farm use |
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glutaraldehyde
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glutaraldehyde:
- inanimate objects - 2% +S |
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halogens
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halogens:
- chlorines, iodines +S: right pH |
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phenolics
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phenolics:
- acts in organic matter -S |
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detergents
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detergents:
- chlorhexidine - S |
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survival of pathogenic bacteria in favorable environment
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survival of pathogenic bacteria in favorable environment:
1. Mycoplasma: 3 d 2. Leptospira: 10 d 3. Mycobacterium bovis: 6 mo 4. Salmonella, Brucella: 8 mo 5. Fungal spores: 10 mo 6. Bacillus anthracis: >50 years in soil |
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disinfection and disease control
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disinfection and disease control:
1. autoclave where possible 2. cleaning prior to disinfection: except anthrax 3. disinfection: 30 min contact time 4. formalin 5%: 4hr, anthrax 5. spores: not alcohols, phenolics 6. peracetic acids and chlorine dioxide: tuberculocidal |
