-
buffers (3)
- salt of phosphate
- peptone
- amino acids
-
more tolerant of pH extremes - bacteria or fungi?
fungi
-
plasmolysis
osmotic water loss of bacteria in hypertonic environment
-
plasmolysis exceptions?
- extreme halophiles
- facultative halophiles
-
extreme halophile example
halobacterium
-
chemical requirements for growth? (3)
- oxygen
- nitrogen, sulfur and phosphorus
- trace elements
-
rhizobum
Nitrogen fixin bacterium associated with legumes (soybeans, peas, lentil)
-
quanternary ammonium componds (quats)
- microbial chemical method of control
- most effective against gram + bacteria, many fungi & amoebas, many viruses
- NOT effective against gram - bacteria
- MOA: disrupts plasma membrane
-
synthetic antimicrobial drugs (3)
- Ethambutol
- Isoniazid
- Sulfonamides/Sulfa Drugs
-
Ethambutol (synthetic)
- against Mycobacterium
- inhibits cellular metabolites
-
Izoniazid (synthetic)
- against Mycobacterium tuberculosis
- inhibits mycolic acid synthesis (cell wall)
- used w. rifapin or ethambutol (synergism)
-
sulfa drugs
- bacteriostatic
- inhibit folic acid synthesis for nucleic acids
-
antibiotics
naturally occuring chemicals produced by some bacteria and fungi
-
Penicillins
- core structure: beta-lactam ring
- natural (G and V): effective against = gram + cocci and bacilli, spirochetes that cant produce pencillinases
-
problems with natural penicillins
- narrow spectrum of activity
- susceptibility to penicillinases (cleave beta lactam rings)
-
semisynthetic penicillins (3)
- broaden activity
- resist penicillinases
- ex: ampicillin
- amoxycillian
- methicillin
-
Cephalosporins
- similar to penicillins (inhibit cell wall synthesis)
- good if allergic to penicillin
- resist penicillinases
- effective against some gram - bugs
-
Cephalosporins example (1)
cephalothin : against pseudomonas aeruginosa
-
carbapenamens
- relatively new, broad spectrum
- inhibit cell wall synthesis
-
carbapenamens example(1)
primaxin - effective against 98 % orgs from hospital pts
-
tetracycline - produced from what bacteria?
streptomyces
-
tetracycline - MOA
inhibit protein synthesis - ribosomes
-
tetracycline - high doses cause
diarrhea, nausea, teeth blackening in children, liver & kidney damage
-
tetracycline- effective against?
- gram + and - bacteria
- rickettsias
- chlamydiae
- mycoplasmas
-
semisynthetic tetracycline
deoxycycline - retained in body longer
-
aminoglycosides - produced by what bacteria
streptomyces spp.
-
aminoglycosides -MOA
inhibit protein synthesis
-
aminoglycosides - problems (2)
- microbial resistance
- patient side effects
-
aminoglycosides examples (4)
- streptomycin
- neomycin
- tobramycin
- gentamicin (against proteus, escherichia, klebsiella)
-
polypeptides - what bacteria produces? two examples?
- bacillus spp.
- ex: bacitracin, polymyxin B
-
polymyxin B = polypeptide (bacillus spp.)
against gram - bugs (psuedomonas spp)
-
bacitracin = polypeptide (bacillus spp.)
- inhibit cell wall synthesis, topically
- against staphs, streps, some gram - like Neisseria spp.
-
Vancomycin - MOA
inhibits cell wall synthesis
-
vancomycin
- chemically unrelated to other antibiotics
- toxic to pts and hard to administer
- narrow spectrum of activity
- works WELL against MRSA
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