ch. 13 + 14 - AGENTS AND ABX ONLY Flashcards
what ABX class/drugs inhibit cell wall synthesis?
- natural penicillins: PCN V and PCN G.
narrow. only gm (+) - penicillinase-resistant: Oxacillin.
semi-synthetic. narrow, only gm (+). - aminopenicillins: Ampicillin.
broad spectrum. not resistant to penicillinase. - penicillin + B-lactamase inhibitor: Augmentin.
Amoxicillin + Clavulanic acid.
broad spectrum AND resistant to penicillinase. - carbapens: Primaxin.
Impenem + Cillastatin.
the most broad spectrum; a last line of defense.
it prevents ABX from being degraded in the kidneys. - monobactams: Aztreonam.
narrow. only gm (-)
fully synthetic. - cephalosporins: 1-5 gens.
1st gen - narrow. only gm (+)
2nd - 5th gen - broad. - polypeptides: Bacitracin and Vancomycin.
narrow. gm (+).
non-B-lactam.
- Bacitracin is for tropical use.
- Vancomycin is the last line of defense used to treat resistant S. aureus INFXS (MRSA). - anti-mycolic acid: isoniazid and ethambutol.
- isoniazid: inhibits the SYNTHESIS of mycolic acid.
- ethambutal: inhibits the INCORPORATION of mycolic acid into the cell wall.
what drugs inhibit protein synthesis?
!! the only bacteriostatic category.
- Nitrofurantoin: fully synthetic and broad spectrum.
PRODRUG: converted/activated by the enzyme nitrate reductase from the microbe itself.
attacks the ribosomal proteins. - Chloramphenicol: broad spectrum and fully synthetic.
inhibits the polypeptide formation between amino acids, causing mRNA misreading.
attacks the 50S subunit of the 70S ribosome.
- TREATS: rickettsial, like lime disease.
- SIDE EFFECT: suppresses bone marrow, which causes hemoglobin levels to drop. - Aminoglycosides: streptomycin, neomycin, gentamycin.
broad spectrum.
attack the 30S subunit of the 70S ribosome.
attacks the amino acid sugars which are attached by glycoside bonds.
- SIDE EFFECT: can cause auditory damage like tinnitus. - Tetracycline: broad spectrum and an antibiotic.
interferes with tRNA attachment, which is what binds amino acids to mRNA.
- TREATS: rickettsial and chlamydia; penetrates tissue. - macrolides: Erythromycin.
narrow. only gm (+).
PCN G alternative.
blocks the ribosomal tunnel, therefore mRNA cannot be translated into a protein.
what drugs inhibit nucleic acid replication?
- Rifamycin: RIfampin.
mycobacteria!
- TREATS: leprasy and tubercolosis.
- side effect: red urine, red tears. - quinolones/fluroquinolones: Ciproflaxin (Cipro).
syntheitc. broad spectrum.
inhibits the enzyme DNA gyrase.
- TREATS: UTIS.
- SIDE EFFECT: tendon rupture.
what drugs cause injury to the plasma membrane?
- lipopeptides: Polymyxin B.
narrow. only gm (-).
disrupts the synthesis of fatty acids.
topical formulation.
what drugs cause competitive inhibition of essential metabolites?
- anti-metabolites: Sulfanamides.
drug synergism: sulfanilamide-trimethoprim.
broad spectrum.
- sulfanilamide: on 1st enzyme: competes with the enzyme PABA to prevent making dihydrofolic acid.
- trimethoprim: 2nd enzyme. prevents the formation of tetrahydrolic acid
OVERALL: blocks the microbe from creating folic acid so that proteins and nucleic acids like DNA are not made.
what chemical agents disrupt the plasma membrane?
- phenol: carbolic acid.
used by Joseph Lister as an anti-septic.
the standard for comparison. - phenolics:
i. Cresol: most common. made from coal tar.
ii. O-phenylphenol: a type of cresol found in the disinfectant Lysol. - biphenols: not common. microbes are resistant.
found in hand soaps and lotions; disinfectants.
i. hexachlorophene.
ii. tricloxan: found in mouthwashes. - biguanides: chlorhexidine.
anti-septic. founding surgical hand scrubs.
non-sporical. - essential oils: peppermint, pine, orange.
treats mostly gm (+).
for surfaces and skin. - surface active agents: soaps.
degerm and for emusifcication.
what agents impair protein synthesis and alter the plasma membrane?
- halogens: active against endospores and microbes!
i. iodine:
- tincture.
- iodophors: longer acting.
AND
ii. chlorine:
- bleach.
- chloramine: chlorine + ammonia.
disinfectant used at restaurants.
- chlorine: shuts down the ETC. water sanitation at pools. - alcohol:
i. ethanol: 70% concentration used for biocide.
AND
ii. isopropanol: has no effect on endospores and non-enveloped viruses.
antiseptic + disinfectant such as in rubbing alcohol.
what agents cause protein denaturation?
- heavy metals: use oligodynamic action, which is the ability of small amounts of heavy metals to kill microbes.
i. silver nitrate.
AND
ii. silver sulfadiazine. - aldehydes:
i. formaldehyde: not used. the 1st conservative used in cadavers.
AND
ii. glutaraldehyde: liquid chemical sterilizing agent.
NOT used in humans! used for endospores and mycobacteria.
used for embalming.
antifungal drugs include?
antifungals target ergosterol to injure the plasma membrane.
- Polyenes
i. Nyastatin: treats thrush or oral candida. - Azoles
i. imidazoles like Clotramazole and Micoazole.
treats tropical infections of the skin.
which ABX only treat gm (+) bacteria?
- PCV V and PCN G
- Oxacillin.
- polypeptides: Bacitracin and Vancomycin (MRSA).
- Macrolides: Erythromycin (mRNA. blocks tunnel)
which ABX only treat gm (-) bacteria?
- Monobactam: Aztreonam
- Lipopeptides: Polymyxin B
which ABX treat mycobacteria?
- anti-mycolic acid: Isoniazid (synthesis) and Ethambutol (incorporation).
- Rifamycin: Rifampin. (red tears)
nitrofurantoin
protein synthesis inhibitor.
fully synthetic + broad spectrum
prodrug - must be activated by the enzyme nitrate reductase from the microbe itself. concentrates in urine.
attacks the ribosomal proteins.
can also treat UTI’s.
chloramphenicol
protein synthesis inhibitor.
fully synthetic + broad spectrum
goes after the 50S subunit of the 70S ribosome.
inhibits the polypeptide formation between amino acids.
treats: rickettsial diseases like lime disease.
side effect: suppresses bone marrow, leading to hemoglobin levels in the blood to drop.
aminoglycosides
protein synthesis inhibitor.
streptomycin* (IV and injection), neomycin (tropical in neosporin), gentamycin.
broad spectrum, goes after the 30S subunit of the 70S chromosome.
targets the amino acid sugars linked by glycoside bonds.
side effect: auditory damage. tinnitus.
